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45August, 2003 DOS Times - Vol.9, No.2
C O N T E N T S
DOS TIMESEditor-in-chief
Dr. Jeewan S. Titiyal
Associate EditorsDr. Harish Pathak
Dr. Harminder K. RaiDr. Vijay B. Wagh
Editorial AdvisersDr. K.P.S. Malik
Dr. Pradeep SharmaDr. Ramanjeet Sihota
Dr. Ritu AroraDr. Dinesh Talwar
Special CorrespondentsDr. Ajay Aurora
Dr. Rajib MukherjeeDr. Anita Sethi
Dr. Namrata SharmaDr. Devender Sood
Dr. Pradeep Venkatesh
CoordinatorsDr. Avnish Gupta
Dr. Raju S.Dr. Anand Agrawal
Ms. Monika Choudhary
Published byDr. Jeewan S. Titiyal
forDelhi Ophthalmological Society
Printed byComputype Media
208, IJS Place, Delhi Gate Bazar,New Delhi-2 Tel: 23284148, 23259312
DOS OfficeRoom No. 476, Dr. R.P. Centre
for Ophthalmic Sciences, AIIMS,Ansari Nagar, New Delhi-110029( : 26589549 Fax : 91-11-26588919
Email: [email protected] : www.dosonline.org
T IM E S
EDITORIAL ..................................... 47
CURRENT PRACTICE
w Sutureless Vitrectomy ................... 48S Natarajan, Aneesh Neekhra
w Glaucoma Surgery with FUGOBlade –A Break through inApproach and Technique ............ 51Daljit Singh, Kiranjit Singh,Ravijit Singh
w Manual SICS by Irrigating Vectis:Stepwise Small Tips ..................... 55Samar K. Basak
w Transpupillary Thermo Therapy –An emerging modality in treatmentof Subfoveal and JuxtafovealChoroidal NeovascularMembranes .................................... 59Lalit Verma, Ankur Sinha, Jayaram,H.K. Tiwari
ART OF REFRACTION
w Prescribing the Aging Eye– The Presbyopic Correction ........ 64Monica Chaudhary
OPHTHALMIC APPLIANCES
w Indirect Ophthalmoscopy:Principles, Technique andPractical Tips ................................ 70Vinay Garodia
MANAGEMENT PEARLS
w Visual Rehabilitation afterPenetrating Keratoplasty ............. 73Rajesh Sinha, Jeewan S Titiyal,Namrata Sharma, Rasik B Vajpayeew Chemical Injuries:
Management Guidelines .............. 76Ritu Arora, Vandana Jain, D.K.Mehtaw Management of Dislocated
Nuclear Fragment DuringPhacoemulsification ..................... 80Amit Khosla, Jasmita Popli
REVIEW
w Surgical Approach forOrbitotomy ..................................... 83S.M. Bethariaw Eye Banking – The Present
Scenario in Our Country .............. 88R.V. Ramaniw Proliferative Vitreoretinopathy ... 90
Neena Kumar, Rajvardhan Azad,Yog Raj Sharma, Atul Kumar, Rajpal
COLUMNS
w Journal Abstracts .......................... 66w Forthcoming Events ...................... 90w DOS Quiz No. 2 ............................. 95
TEAR SHEET-2
w RD Colour Coding Chart ........... 103Neena Kumar
Keep October 19, 2003 Free for
MID TERM CONFERENCEof Delhi Ophthalmological Society
Plasma Fugo Blade: Shows the cloud on the 100 micron activated tip of Fugoblade. The yellow cover on the tip is the plasma cloud that has cutting
properties, while the red colour is that of photon cloud that doe not cut
47August, 2003 DOS Times - Vol.9, No.2
EDITORIAL
Dear friends,
The adventof 21st century hasushered in a tre-mendous ad-vancement in thefield of science
and technology at a very rapid pace.More important has been its appli-cation in various spheres of life andone of the most important fieldwhich has seen a revolution of sorthas been Medicine. It would not beprudent to say that along with Car-diac medicine, Ophthalmology isone of the leading branches of clini-cal medicine which has undergonea sea change because of the rapid-ity at which new technology is be-ing used for diagnosis and treat-ment of various ocular disorders.The specialties of Glaucoma andRetina have seen widespread ad-vances in form of development ofsophisticated diagnostic appliances(Ultrasonic Biomicroscopy, OpticalCoherence Tomography etc) newerforms of lasers (PDT and TTT forARMD) and modern microsurgical
instruments which have done awaywith the use of sutures.” MinimalInvasive” technique is the guru man-tra of the day. Earlier we had ush-ered in the concept of small incision-no stitch cataract surgery, thanks toKelman’s Phacoemulsification andnow we have sutureless vitrecto-mies. The Plasma Fugo blade is aclassic example of a new technologywith multipurpose use as high-lighted in the article by Dr. DaljitSingh.
All said and done, it however re-mains to be seen how these ad-vancements are of help to develop-ing countries like ours where manualsmall incision stitchless surgeries aremore popular because of the costbenefit as well as less surgical timein dealing with high volumes ofcataract surgery.
Corneal Blindness is a majorcause of concern as it forms a majorchunk of treatable blindness group.With the availability of Eye Bank-ing services, processing and storageproblems though taken care of, we
are still short of our target as far asprocurement of corneas is con-cerned. We receive many pledgecards, their number is in thousandsbut just a pledge for donation is notsufficient. In fact donation afterdeath is actually very less evenfrom those who have pledged. Thismeans our campaign to increasepledging is a failure. Our focusshould be directed towards increas-ing the motivation of relatives andnext to kin for donation. A unitedeffort is needed by all sections ofsociety to help in achieving this goal.
DOS website dosonline.org hascome back in a new format. Verysoon every member would be ableto logon to the website. I look for-ward to improve the website, spe-cially the discussion forum andnews section along with DOS Timesarchive. With the valuable feedbackand suggestions of our members wecan improve on the shortcomings,if any, and thus give a new look andflavour to the various activities ofour esteemed organization.
!!Attention DOS Members!!
The registration fees for life membership ofDelhi Ophthalmological Society
is now being increased to Rs. 3,100 from1st August 2003
– Secretary DOS
48August, 2003 DOS Times - Vol.9, No.2
Since the advent of couch-ing by Sushrata, ophthalmicsurgical techniques are un-dergoing rapid develop-ments and modifications.The aim is to adopt the tech-nique with best possible out-come by least possible inva-sion of ocular anatomy. Withthe rise in sutureless cataractsurgeries with minimal pa-tient morbidity post opera-tively, vitreoretinal proce-dures also underwent lots ofchanges.
Though sophisticated in-struments and lasers havebeen developed forvitreoretinal surgery but stillthe patient needs to undergo20 gauge sclerotomies andpost operative morbidity be-cause of sutured wounds.Tunnel based sclerotomy byChen4 was suggested to cre-ate self sealing incisions forVR surgery but it requires aconjunctival peritomy andsuturing and is associatedwith complications likewound leakage, extention,dehiscence, hemorrhage, vit-reous and / or retinal incar-ceration, retinal tears, dialy-sis and difficulty in passinginstruments. Modificationsin vitrectomy instrumenta-tion aimed at decreasing thesize of instruments mustachieve a balance betweenability to achieve smaller in-cision sizes versus maximiz-ing instrument functionality,
Sutureless VitrectomyS Natarajan DO, FRVS
Aneesh Neekhra MS,DNB,DOMS,FCPS
recognizing that high instru-ment functionality may notalways be compatible withsmall size.
At first, there were no suit-able materials to use as su-tures in the eye, so the eye hadto be bandaged and healingwas left to its own. This meantthe patient was confined tobed with their head literallysandbagged to prevent move-ment that might jeopardizethe healing process. Overallthe quest for least morbidityfor patient postoperativelyundergoes full circle from Nosuture Era in cataract surgeryto again suturelessvitreoretinal surgery. In theearly 1970s, Machemer1 useda 17-gauge 1.5mm diametermultifunctional instrumentcapable of cutting and aspi-rating the vitreous followedby a smaller vitreous cutter of20 gauge (0.9 mm) designedby O'Malley and Heintz2 in1974. The race for smallerinstruments doesn't end here.In 1990 De Juan andHickingbotham3 designed avariety of 25-guage (0.5mmdiameter) vitreoretinal in-struments and thus the era ofsutureless vitrectomy begins.
Transconjunctival sutu-reless vitrectomy system(TSV) 25 guage developed byFujii et al5 allows self-sealingtransconjunctival scleroto-mies and minimizes surgi-cally induced trauma, im-proves operative efficiencyand hastens postoperativerecovery. The self-sealingsclerotomy obviates the need
for conjunctival peritomyand no sutures are requiredat any conjunctival or scleralopening site. The develop-ment of smaller gauge instru-ments may prevent the incor-poration of multiple func-tions in their design. Alsodue to the smaller size, theinfusion and aspirationrates are reduced. However,
there are settings where thefull capabilities of 19-20gauge instruments may notbe required and smallergauge instruments may bemore desired due to their lessin invasive nature.
InstrumentationThe TSV consists of a 25-
guage microcannula system
Aditya Jyot Eye HospitalAashirwad, 168-D Vikas WadiDr. Ambedkar Road, Dadar T.T.Mumbai - 400 014
CURRENT PRACTICE
Fig.4: Insertion of 25 gaugevitrector through the cannula.The other cannula is keptplugged (Blue) till the introduc-tion of endo illuminator
Fig.3: Removal of trocar leav-ing the cannula in place as achannel for the introduction of25 guage instruments. The in-fusion line can be seen in posi-tion.
Fig.1: 25 gauge 'Entry Site Alingment System"
Fig.2: Array of 25 Vitreo Retinal Instruments
49August, 2003 DOS Times - Vol.9, No.2
and a wide array of vitreo-retinal instruments specifi-cally designed for this oper-ating system. Integral to thisvitrectomy instrument sys-tem is the 25-gaugemicrocannula system. It con-sists of a microcannula, aninsertion trocar, an infusioncannula, a plug forceps, anda cannula plug. The cannularemains in place and newlydesigned smaller instru-ments can be introducedthrough it to perform surgeryin the posterior segment.
The microcannula con-sists of a thin- walled polya-mide tube 3.6 mm in lengthwith an inner / outer diam-eter of 0.57/0.62 mm. A col-lar is present at the extraocu-lar portion, which can begrasped with forceps to ma-nipulate the microcannula.A funnel - shaped entry wasdesigned to facilitate accessof instruments. Once in-serted through the eye wall,sutures are not required tohold the microcannula inplace. The microcannulas areinserted through the con-junctiva into the eye by meansof a trocar that, when insertedinto the cannula, forms a con-tinuous bevel with themicrocannula, allowing easeof entry. The trocar is thenwithdrawn leaving the can-nula in place. The main pur-pose of the 25-gaugemicrocannula system is tomaintain the alignment be-tween the conjunctival andthe scleral entry site, becauseno prior conjunctival dissec-tion is required for insertionof the trocar and cannula.Therefore, the 25-gauge can-nula system is referred to asan "entry site alignment sys-tem" (EAS). (Fig.1)
The 25-gauge infusion
cannula consists of a smallmetallic tube 5mm long withan inner/outer diameter of0.37/0.56 mm. The intraocu-lar portion of the infusioncannula is directly insertedinto the eye through themicrocannula. A collar at theextra ocular portion allowsthe infusion cannula to beheld and facilitate its ma-nipulation.
A wide array of vitreo-retinal microsurgical instru-ments (Fig.2) complyingwith the 25-gauge standardshave also been designed.These include a high-speedvitreous cutter, illuminationprobe, intraocular micro for-ceps, rigid retinal pick, flex-
ible and extended retinalpick, tissue manipulator, la-ser probe, diathermy probe,aspirator and others.
Infusion and Aspirationrates
Due to the small size theinfusion and aspirationrates at various settings arereduced by 6.9 and 6.6 timesrespectively when comparedwith the 20 guage system6.
Time Measurementcomparison
In a published study doneby Fujii GY et al6, the meantotal operative time wasfound to be significantlygreater for the 20 guage (26min 7sec) than for the 25gauge vitrectomy (17min17sec). The differences in
operating times were notice-ably greater for the 'initialopening' and 'final closing'steps of the surgery. The'vitrectomy' time was an av-erage of 1 min 23 sec longerusing the 25 gauge TSV.
TechniquesStretching the conjunctiva
at the beginning of the pro-cedure with cotton tippedapplicator before entering thepars plana ensures that at theend, when the trocar is re-moved, the conjunctiva willhelp cover the hole made bytrocar. Three entries usingtrocar cannulas are made inthe inferotemporal, supero-temporal and supreonasal
quadrants. The trocar creates0.5mm conjunctival andscleral incisions. An infu-sion cannula is inserted intothe IT cannula and plugsused to temporarily closeother entry sites till use (Fig3,Fig4)
The TSV requires somemodifications of techniqueduring vitrectomy. Maxi-mum cut rates are requiredto achieve optimal fragmen-tation of intraocular tissueand to decrease the possibil-ity of obstruction in aspira-tion line, which is narrowerthan standard 20-guagevitrectomy systems. The vit-reous cutter is used withmaximum aspiration rate(500mmHg) and concomi-tant high cutting rate of1500cpm. The difference be-
tween minimum infusionrate and maximum aspira-tion rate is larger in the TSVsystem, which allows forgreater safety margin againsthypotony during aspiration.The 25-gauge cannulashould not be used concur-rently with standard 20guage vitreous cutter as itmay result in hypotony dur-ing aspiration resulting formfunctional discrepancy be-tween infusion and aspira-tion rates of both systems. TheTSV system can provide abetter gas fill as it is a moreclosed system. The 25 g. cut-ter can be used to sweepblood off the retina.
After removal of the trocarpressure is applied to eachsite to ensure that they are notleaking. The conjunctivashould snap back, if the con-junctiva begins to swell andform a bleb, there may be aleak. Some surgeons prefer totake a fixation forceps andmanually close the woundand hold it for a moment un-til the underlying vitreouscan block the wound siteform beneath the sclera.
IndicationMany vitreoretinal proce-
dures that do not involve ex-tensive dissection, are likelyto benefit from a less invasiveprocedure, because much ofthe surgical trauma in thosecases may be related to theconjunctival and scleral in-cision procedures. The TSVsystem has been used inepiretinal membrane peeling,macular hole surgery, retinaldetachment with minimal orno proliferative vitreore-tinopathy, branch retinalvein occlusion sheathotomy,vitreous hemorrhage,endophthalmitis. The TSV is
CURRENT PRACTICE
TSV allows self-sealingtransconjunctival sclerotomies and
minimizes surgically induced trauma,improves operative efficiency and
hastens postoperative recovery
50August, 2003 DOS Times - Vol.9, No.2
of potential benefit in smallereyes of children where use ofstandard instruments mayincur technical difficultiesrelated to the ocular size6.
With the rise in healthawareness, more and morepatients present early withless complications. Suchcases can be better dealt withTSV 25 System. Newer sur-gical indications likevitrectomy for diabetic macu-lar edema makes the scopeof this system further more.Glaucoma prone patientsundergoing vitreoretinal pro-cedures may have a bettermobile and healthy conjunc-tiva for the future anti-glaucoma surgery. Mean-while combined suturelesscataract and vitreoretinalsurgery by TSV 25 G Systemmakes the major ophthalmicsurgery a day care procedurewith least possible morbid-ity for the patients, the ulti-mate goal for any surgeon.
LimitationsThe TSV system should
not be use on previouslyscarred operated eyes as it isdifficult to enter the scleraand the trocar may bend. Inhighly myopic patients withthin sclera, wound does notclose in the same manner asother patients. It is difficultto infuse silicone oil through25-gauge cannula. In retinaldetachments with prolifera-tive vitreoretinopathy, be-cause of smaller port and di-ameter of 25-gauge cutter, thecutting and aspiration ratesare reduced so its efficiencyin dense fibrous proliferationmay be limited. The in-creased flexibility of 25 gaugeinstruments may not be ableto control eye positions dur-ing the surgery. There is also
a theoretical possibility ofsuture less sclerotomies serv-ing as a conduit for the entryof bacteria.
Surgeons may experiencewound leaks that need to besutured in their initial cases.A re-operation the next dayis worse than suturing at thetime of closure.
ResultsBeing a relatively new
technique few studies areavailable in literature. Fujiiet al described6 their initialexperiences in a consecutiveseries of 35 eyes. They usedthe TSV in cases of retinaldetachment, retinopathy ofprematurity, Norrie disease,epiretinal membrane, macu-
lar hole, branch retinal veinocclusion, persistent diabeticmacular edema and vitreoushemorrhage and retainedlens material post cataractsurgery.
No wound leakage wasseen in any case and the post-operative IOP was main-tained. In idiopathicepiretinal membrane cases,core vitrectomy and mem-brane peeling was performedsatisfactorily. Sheathotomyat the pathologic arterio-venous crossing was per-formed by using a nitinolpick that can be extended toadjust its curvature, whichenables the surgeon to get
optimal positioning at thedissection point of the cross-ing. It was possible to peelepiretinal membranes andperform sheathotomy with-out prior vitrectomy in somecases. Treatment of retinaldetachment was successfulis all cases, although none ofthese cases had severe pro-liferative vitreoretinopathy.
In our initial experienceTSV was found to be suitablein cases with epiretinal mem-branes, macular hole andfresh vitreous haemorrhage.The TSV system was used in4 cases requiringVitreoretinal procedures.The four cases wereEpiretinal Membrane in apost laser diabetic patient,
Idiopathic Macular Hole,Retinal Detachment and Vit-reous Hemorrhage. Weevaluated the operative time,wound closure, limitationsof the system and the out-come of surgery. The averageoperating time was 30 minsand all the wounds showedgood closure with no woundleaks. The epiretinal mem-brane was successfully re-moved with an increase ofthree lines in visual acuity.The macular hole showedflat edges with an open hole.The retinal detachment un-derwent resurgery for recur-rence. The vitreous hemor-rhage was old and repeat-
edly clogged the cutter. Prob-ably, further improvement intechnology will makes usable to handle complicatedcases in the near future.
ConclusionIn select cases where full
capabilities of conventionalvitrectomy system are not re-quired, the 25-gauge TSV sys-tem can offer better patientcomfort, care and manage-ment by reducing operativetime effectively. With moreadvancement in technology,future of sutureless 25 Gvitrectomy and thus thevitreoretinal surgery goingfor a major turning point.
References1. Machemer R, Buettner H,
Norton EW, PArel JM.Vitrectomy a pars plana ap-proach. Trans Am AcadOphthalmol Otolaryn gol 1971;75:813 20.
2. O’Malley C, Heintz RM Sr.Vitrectomy with an alterna-tive instruments system, AnnOphthalmol 1975; 7: 585-8; 591-4.
3. De Juan E Jr, HickingbothamD. Refinements in micro-instruementation for vitre-ous surgery. Am J Ophthalmol1990; 109: 218-20.
4. Chen JC, Sutureless parsplana vitrectomy throughself-sealing sclerotomies.Arch Ophthalmol 1996;114:1273-5
5. A new 25- guage instrumentsystem for transconjunctivalsutureless vitrectomy sur-gery: Fujii GY, De Juan E Jr,Humayun Ms, Pieramici DJ,Chang TS, Ng E, Barnes A,Wu SL, Sommerville DN.Ophthalmology 2002 Oct;109(10): 1807 12; discussion 1813.
6. Initial experience using thetransconjunctival suturelessvitrectomy system forvitreoretinal surgery: FujiiGY, De Juan E Jr, HumayunMS, Chang TS, Pieramici DJBarnes A, Kent D. Ophthalmol-ogy 2002 Oct; 109(10): 1814-20.
CURRENT PRACTICE
TSV system has been used in epiretinalmembrane peeling, macular hole sur-
gery, retinal detachment with minimalor no proliferative vitreoretinopathy,branch retinal vein occlusion sheatho-
tomy, vitreous hemorrhage,endophthalmitis
51August, 2003 DOS Times - Vol.9, No.2
A revolutionary new cut-ting technology is set to bringabout a revolution in allfields of surgery. Luckily forus, it started with ophthal-mology, because the inven-tor, Dr. Fugo happened to bean ophthalmologist. He tooknearly 20 years to develop it.
The toolThe Fugo Blade (after its
inventor, Dr. Richard Fugo)is truly a novel cutting instru-ment, which employsplasma energy for ablatingincision paths in tissue in amanner similar to the Eximerlaser and is approved for in-traocular use by the Foodand Drug Administration(FDA) in the USA. The instru-ment consists of a console, ahand-piece and a disposabletip. Three rechargeable bat-tery cells provide the energy.One charge lasts for over anhour of cutting time. This in-dicates how little energy isneeded to energize the cut-ting tip. But the plasma en-ergy that develops on a 100-micron filament of the dis-posable tip is phenomenalfrom many points of view. Itis visible under high magni-fication, looking like bees ona honey cone. This plasmaablates in such a fashion thatit creates a smooth wall alongthe ablation path. The secret
Glaucoma Surgery with FUGO Blade–A Break through in Approach and TechniqueDaljit Singh, Kiranjit Singh, Ravijit Singh
is that the electromagneticwaves are brought to a sharpfocus by the electronics in theconsole and in the handle,onto the tip of the incisingfilament. The electromag-netic oscillations are tunedto the tissues, so that the mo-ment the activated tiptouches a tissue, the tissuemolecules start resonating.At the activated tip-tissuejunction plasma energy isproduced that is actually vis-ible to the naked eye. Whenlooked under a high powermicroscope, the plasma en-ergy is visible as a 25-50 mi-cron wide pulsating yellowcloud on the activated tip.Around the plasma cloud,there is reddish much widerphoton cloud. The cuttingpower resides in the plasmacloud. The plasma sustainsitself by feeding on the tissue,which is ablated in the tru-est sense. The plasma cloudoscillation instantly shattersthe macromolecules of thetissue into small fragmentsand throw them out. Theplasma energy at the tip is ata very high temperature.However, the heated fielddoes not extend beyond 25microns of the plasma. TheFugo Blade has an importantfunction of non-cauterizinghemostasis in cut tissue. Itdoes this in two ways- theablation of the vessels is thecutting path and secondly bythe particle oscillation,which tends to plug the
small bleeding vessels.
How is it used?The Fugo blade is held like
a pen. The surgeon keeps aneye on the 100 micron tip. Hemakes up his mind in whichdirection the tip is to bemoved after activation- side-ways or up and down, andat what angle. Planning isvery important. The reasonis that the moment the acti-vated tip touches the tissue,the touched part disappears.The surgeon should hold hisbreath when doing a fine andprecise maneuver. Gettingsupport from the forehead ofthe patient helps in stabilityand better control The acti-vation switch is under thefoot. Keep the foot away ex-cept at the actual moment ofuse.
Glaucoma SurgeryFugo blade has untold ap-
plications, that we have ex-perienced in cataract, glau-coma, extra ocular surgery,oculoplastic surgery, vitreo-retinal surgery and sac sur-gery. Outside ophthalmol-ogy it has been extensivelyused in ENT surgery in oneinstitution in Amritsar. In thefollowing section, we shalldescribe our experiences inglaucoma surgery.
Acute glaucoma emergencyWhen the eye is fiery red,
the cornea is steamy, the pu-pil is widely dilated, the eye
is stony hard and the patientis in great agony. Similarcondition is seen in manycases of trauma, aphakia,pseudophakia, absoluteglaucoma and rubeosisiridis. It may be a dire emer-gency in which medicaltreatment may take hours totake effect. We use Fugo bladeto deal with emergency asfollows:
a. Inject 3 ml of ligno-caine subconjunctival. Waitfor 15 minutes to take effect.Massage till the conjunctivalballooning disappears.
b. The superior conjunc-tiva is pulled down on thecornea with an old fashion 3mm wide fixation forceps. Ithas blunt teeth and does notpuncture the conjunctiva.
c. Clearly visualize thelimbus as a landmark. Thiscan be facilitated if the limbalconjunctiva is marked withgentian violet. As the con-junctiva is pulled down asharp blue line of the limbusis seen.
d. A point is visuallychosen for making the track.The track can be made in tothe anaterior or the posteriorchamber as the situation de-mands. A 4 mm long 100 mi-cron Fugo blade tip is cho-sen.. It is placed at the se-lected point and directed to-wards the anterior chamberor the posterior chamber. Anactivated tip cuts so fast thatyou have to make up yourmind, how the tip shall be
CURRENT PRACTICE
Dr. Daljit Singh, Director,Dr. Daljit Singh Eye Hospital,Sherawala Gate, Amritsar.
52August, 2003 DOS Times - Vol.9, No.2
moved, once it is activated.Move the activated tipquickly. In a fraction of a sec-ond the tip is in the anteriorchamber or the posteriorchamber as desired. The mo-ment it encounters fluid it isinactivated automatically.The tip is withdrawn. Aque-ous is seen seeping throughthe track just created.
e. The conjunctiva is re-leased. The seeping aqueousstarts making a filtrationbleb. No suture is required.The emergency operation isfinished.
1. Doing a routine glaucomaprocedure:
Fugo blade takes the placeof three manual instruments,the forceps, scissors and he-mostat. The following kindsof procedures can be done:
a. Trabeculectomy:Theplasma energy cuts the con-junctiva, tenon capsule,makes scleral flap easily andwithout bleeding. The cutedges of every structure aresharp and clean. The tissuessuffer minimal trauma andthe surgery time is reduced.
b. Non-perforating proce-dures: Any kind of non-per-forating procedure can beperformed with ease. The tis-sue ablation with plasma tipproceeds at a leisurely pacewithout any bleeding. Theonly precaution is to keep astrict visual control on theablation process, so that theanterior chamber is notopened. The seepage can beverified by instilling a dropof trypan blue, which will beseen as getting washed outby the seeping aqueous. If sodesired, the surgeon can con-vert and create one or more100 micron tracks for filtra-tion.
2. Transciliary filtrationAs a new micro-surgical
procedure it is a new. Earlierin 1979 the senior author(DS) had presented “Trans-ciliary Filtration for Intrac-table Glaucoma” in AIOSand OSUK. It described mak-ing a filtration track throughthe pars plana of ciliarybody. The technique hasbeen in use in our set up tillrecently. We have been do-ing the new micro-surgicalTrans-ciliary filtration (TCF)for nearly 2 years and haveperformed over 350 opera-tions. Currently, a number ofUS ophthalmologists are do-ing glaucoma surgery proto-col with Fugo blade.
TCF makes a 150 micron(100 micron filament and 50micron of plasma layer) fil-tration track between theposterior chamber and thesubconjunctival space. Weknow the precise width of thetrack, since that is how farthe plasma activity of Fugoblade tip extends. There aremany ways to achieve. Themain differences are in themaking of the conjunctivalflap and the preparation ofthe scleral surface before en-tering the ciliary body.
The following is the de-scription of the techniquethat has been followed formore than 20 months:
a. About 8 mm of con-junctiva is detached and re-tracted from the limbus, so asto expose about 3 mm of thesclera in widest part.
b. The bleeding pointsare closed by non-cauteriz-ing hemostasis with Fugoblade tip at the lowest set-ting. Only the bleedingpoints are touched, so thatthe scleral surface remains inoriginal condition. That is
CURRENT PRACTICE
Figure 1: Shows the cloud on the 100 micron activated tip of Fugoblade. The yellow cover on the tip is the plasma cloud that hascutting properties, while the red colour is that of photon cloudthat doe not cut.
Figure 2: This patient of PKP came as a severe emergency withIOP near 70 mm Hg. A 100 micron track was made 1 day earlier.
Figure 3: Shows a filtering bleb 3 hours after TCF operation.
53August, 2003 DOS Times - Vol.9, No.2
not the case when a bipolarcautery is applied.
c. About 1 mm behindthe limbus, a scleral pit about0.6 mm wide is ablated. Theablation is carried to the levelof the ciliary body. This maybe done with the standard100 micron tip or with a flatend 0.6 mm tip. The transi-tion from the sclera to the cili-ary body is clearly seen as achange from white to blackappearance of the depth ofthe pit. In many cases wehave also done wider thin-ning of the sclera, before mak-ing a pit that reaches the cili-ary body.
d. The ciliary body ispenetrated to reach the pos-terior chamber. A 100 microntip is used for this purposeat medium setting. The mo-ment the aqueous reservoirin the posterior chamber isreached, the fluid moves out-wards and inactivates theFugo blade tip.
e. A drop of trypan blueis instilled to make sureabout the drainage.
f. The conjunctival flap
is replaced back to the lim-bus with one or two 40 mi-cron steel sutures.
3. TCF Sans ConjunctivalFlap
This is our latest approachto glaucoma filtration sur-gery. The surgery is done asfollows:
a. The conjunctiva ismassaged downwards sothat it hangs over the cornea.The limbus is clearly visiblethrough the conjunctiva. It isnecessary to make sure thatthe location of the limbus inrelation to the pulled downconjunctiva does not changeduring surgery. To achievethis, the conjunctiva ispressed against the limbuswith a thin dull long and stiffinstrument. Currently we usethe back side of disposablerazor blade fragment. It keepsthe limbus well defined andalso stabilizes the eye.
b. The conjunctiva closeto the limbus at this point ap-pears stretched and closelyapplied to the sclera, ofcourse with the intervening
tenon capsule. Without let-ting the tissues move, Fugoblade is used to make a holein the conjunctiva plus what-ever tenon capsule may bethere, after which a pit ismade in the sclera as usual,till the ciliary body isreached.
c. The eye is kept stabi-lized in the same position.The fixing hand is notmoved. With the other hand,Fugo blade tip goes throughthe ciliary body in to the pos-terior chamber. This is sig-naled by the seepage of theaqueous that is so obvious,which may be further con-firmed by instilling a drop oftrypan blue, which getswashed away immediataely.
d. The pressure on thelimbus is released, by simplylifting the razor blade frag-ment. The pulled down con-junctiva is allowed to retractupwards. As this happens,a filering bleb starts forming.The hole in the conjunctivais seen at a distance of 7 to 10mm. away from the tans-cili-ary filtering track. It may be
left as such or a suture beapplied to close it.
Trans-conjunctival TCFappears to have some advan-tages like reduced trauma tothe tissues, no bleedingpoints to be tackled and prac-tically instant recovery. Wehave done only 8 cases withthis technique. They have ashort follow up. If satisfac-tory results are obtained, itwill be the beginning of theend of the conjunctival flapera in glaucoma surgery.
A summary of resultsobtained in PrimaryglaucomaNumber of cases:POAG : 109PACG : 104Total : 213Preoperative intraocularpressure:Maximum : 70 mmMinimum : 24 mmAverage : 41.5 mmPostoperative Complications:Hyphema : 2Choroidal detachment : 2Subconjunctival
hematoma : 2
CURRENT PRACTICE
Figure 5: Showing the filtration area 1 year after TCF operation.The conjunctiva appears quite healthy.
Figure 4: Showing the filtering bleb after Trans-conjunctival TCF3 hours after surgery.
54August, 2003 DOS Times - Vol.9, No.2
Follow up :Maximum : 17 monthsMinimum : 4 monthsAverage : 5 monthsRe-operations : 26 (12%)On local
medication : 22 (10.3%)Final intraocular pressure:< 5 mm : 9 (4.2 %)6-10 mm : 51 (24 %)11-15 mm : 74 (34.7 %)16-20 mm : 79 (37 %)
CommentsTrans-ciliary filtration
surgery is a viable surgicaloption as we have found. Byseeking the drainage fluidfrom the posterior chamber,all the anterior chamber com-plications whether operativeor postoperative have beenremoved. The complications
of small hyphaema and cho-roidal detachment were selflimiting and recovered spon-taneously. No iridectomy isdone during the operationthus avoiding a source ofhyphaema. In cases of angleclosure glaucoma, we haveobserved immediate deepen-ing of the anterior chamber,as fluid starts draining fromthe posterior chamber. Post-operative recovery is fast andthe patient is fit to be dis-charged after 3 hours. Thereis no need for mitomycin ap-plication, barring a rare case.
The filtered fluid isdrained in to the lymphatics.We mark lymphatics in ev-ery case, just before the startof the operation. If lymphat-ics are poorly marked, the
chances of surgical successare reduced. Tissue manipu-lations, bipolar cautery andmitomycin application prob-ably do much damage to thelymphatics. In doing TCF, wetry to avoid these factors.
In short:There is a clear possibil-
ity of a revolution, in glau-coma comparable to whathappened in the field of cata-ract surgery. A revolution issupposed to occur when thesurgeons on the front linehave either adopted the tech-nique or they are consider-ing it. This process takessome time. In the present case,once the surgeons begin tounderstand the versatility ofthe new tool, the Fugo blade,
CURRENT PRACTICEthe revolution will not be far.The authors have no finan-cial interest in the product.
References:
1. Singh Micro-filtration forglaucoma, a new tech-nique. Daljit Singh. Tropi-cal Ophthalmology. 2001;5:7-11
2. Transciliary Filtrationand Lymphatics of Con-junctiva- A Tale of Dis-covery. Daljit Singh.Tropical Ophthalmology.2002; 2:9-13
3. Transciliary Filtration Us-ing the Fugo Blade. DaljitSingh and Kiranjit Singh.Ann. Ophthalmol 2002;34(3):183-187
Programme for DOS Monthly Clinical Meeting for August 2003Venue: Auditorium, Sir Ganga Ram Hospital, Rajendra Nagar, New Delhi
Date & Time : 30th August, 2003 (Saturday) at 2.30 P.M.
Case Presentation
1. Congenital Anophthalmos with Ectopic Brain Tissue ................... Dr. Jasmita Popliin the Orbit
2. Periocular Necrosis Following Local Anaesthesia for .................... Dr. Anita Sethifor Cataract Surgery
Clinical Talk
l New Frontiers in the Management of Retinal ................................. Dr. S.N. JhaVascular Blocks
Mini Symposium: Rapid Fire Session
Chairmen/Moderator: Dr. A.K. Grover
What shall I do now? (Clinical Situations/Surgical Dilemmas/Operative Complications)
Moderator ..................................................................................................... Dr. A.K. Grover
Panelists ......................................................................................................... Dr. V.K. Dada,Dr. R.L. Kaul,Dr. Harbansh Lal, Dr. S.N. JhaDr. Amit Khosla
Panel Discussions : 20 min.
55August, 2003 DOS Times - Vol.9, No.2
During the last two de-cades there is a tremendousleap forward in cataract sur-gery all over the world. In onehand Phacoemulsificationwith foldable IOL has gainedits confidence in Westernworld, and on the otherhand, Manual Small IncisionCataract Surgery is definitelya breakthrough in countrylike India. Phacoemulsi-fication, the term itself sug-gests the mechanism ofnucleus removal from theeye. But, we do not speakabout method of nucleus de-livery in manual SICS to ourpatients. If we think criti-cally, the basic tangible as-pect in small incision cata-ract surgery to the patient isstitchless cataract surgerythrough a relatively asmaller incision.
In manual SICS, 'S' standsfor small, and we also talk toour patient about the small-ness of incision in cataractsurgery. Mature and hardcataract is a rule in our coun-try, not an exception. In fact,we are overburdened withsuch types of cataract. So, de-pending upon the size andhardness of the nucleus, wedesign the incision length,which may vary from 5.5 mmto 7.0 mm or even 7.5 mm inmanual SICS (Fig 1). It varies
Manual SICS by Irrigating Vectis:Stepwise Small TipsSamar K. Basak, MD, DNB
Disha Eye Hospitals & ResearchCentre, Barrackpore,West Bengal - [email protected]
from patient to patient. So forall practical purpose, inmanual SICS, 'S' is not al-ways Small to us. The 'S's(Aces) for us are - Safe,Sutureless, Stressless, Stable,Secure and Self-sealing cata-ract surgery with a Shortlearning curve. Above all itis Simple with Simple instru-mentation (Fig:2). Let us dis-cuss in a Small way of all thesteps which we have founduseful for the success of thesurgery.
First of all, there are somecriteria for ideal case selec-tion for the beginners:1. Clear cornea with healthy
endothelium.2. A well dilated pupil.3. A normal anterior cham-
ber depth.4. Intact zonular attach-
ment.5. Immature cortical cata-
ract, Nuclear sclerosisGrade II and III.As the surgeon learns this
technique, gradually he canmaster this procedure virtu-ally in all types of cataract.
AnaesthesiaPeribulbar or Retrobulbar
anesthesia, anything can begiven. The surgery can beperformed even under 'Topi-cal' anaesthesia. But the im-portant point is not to giveexcessive bulbar massage orpressure with Super pinky.That means, there should notbe much hypotony, other-wise scleral tunnel making
would be difficult.
Superior Rectus Bridle Su-ture
Superior rectus bridle su-ture is given to manoeuvrethe globe forward and down-wards. With irrigating vectistechnique, it is essential togive counterforce during thenucleus delivery and some-times during epinucleus de-livery. A specially designedepiscleral forceps can be usedalternately to minimize supe-rior rectus muscle injury.
Conjunctival FlapMany a time, we do not
bother about this part of thesurgery. A triangular fornix-based conjunctival flap ispreferred (Fig 3). First give asmall radial cut with the scis-sors. Do a good undermin-ing dissection of it along withTenon's capsule, and thencut along the limbus for 6-8mm. The important point isto clear all the Tenon's (andepiscleral) attachments fromthe sclera. Otherwise, firstexternal scleral groove inci-sion may not be in perfectdepth in all length. A gentleand just adequate cautery(wet field cautery is alwaysbetter) is applied. Care hasto be taken not to over cau-terize over the scleral bed.After completion of surgerythe flap is gently reapposedand cauterized.
6 mm 2.0 mm behind
Fig 1: Depending upon the nuclear size the incision can be planned.
7.5 mm 2.5 mm behind
Fig 2: Simple instrumentation in Manual SICS with IrrigationVectis Technique
CURRENT PRACTICE
56August, 2003 DOS Times - Vol.9, No.2
IncisionIn manual SICS, incision
is the main concern. The verygoal of this surgery lies onthe self-sealing property ofthe incision. This incisionhas three components:1. External scleral incision,2. Sclero-corneal tunneling
and3. Internal incision
1. External Scleral IncisionThe external incision may
be Straight, Frown-shaped orChevron (Fig: 4). It is usuallygiven 1.5 to 2 mm behind thelimbus and 5.5 to 7.5 inlength. The highlightingpoint is- the incision is to begiven at right site and in ad-equate depth. If we plan thatbecause of nuclear hardnessor for some other reasons theincision length is to be larger,we have to shift the incisionmore posterior.
It is always preferable toshift the incision towardsright side of the superior lim-bus. As our pronation actionof arm is more active thansupination, there is mechani-
cal obstruction of the arm bythe body, if we are perfectlyat the centre of the superiorlimbus. So, we must centerthe incision at 11 o'clock po-sition rather than 12 o'clockposition. That means for theright eye it is slightly supero-temporal in position and forthe left eye it should beslightly supero-nasal.
2. Sclero-corneal Tunnel-ing
Ø After making initialgroove, dissect little at theexternal scleral lip.
Ø Split the sclera from thecenter, as it is easier.
Ø Overlap the split area tocreate a new area.
Ø Wriggle the scleral split-ter forward.
Ø For the sides, direct theblade centripetally.
Ø The cornea is more curvedthan the sclera; so put theheal-down of the splitteras the cornea is ap-proached.
Ø Never hold the scleral lipduring any point of dis-section of tunnel or dur-
ing any step of surgery.Scleral Pockets: Scleral
pockets are like pleats of ourtrousers. They accommodatenot only the diameter of thenucleus but also its thick-ness. They give more spacefor large and thick nucleus(Fig 5). They are not neces-sary in all cases especially insofter nucleus. They maycause bleeding from tunneland postoperatively theymay excite more tissue reac-tion.
3. Internal incisionThe internal incision
should be curved along thecurvature of the limbus. If itis straight, it has to go moretowards the centre of the cor-nea to get same desiredlength of the internal inci-sion (Fig: 6). That means moreastigmatism and might bemore endothelial cell loss.
The dimpling-down 2.8mm keratome entry must beparallel to the external inci-sion. If the entry is oblique,the internal incision runsinto the cornea on one side
and falls short on the otherside (Fig: 7). Towards thesides the keratome shouldmove centripetally. It shouldcut during the entry of thekeratome and not duringexit. Care has to be taken notto injure endothelium withthe tip of the keratome dur-ing its manoeuvre towardsthe sides.
Side-port entryIt is an optional situation.
For the beginner it helps toclear sub-incisional cortex.One has to use smaller cali-ber of bi-way canula throughthis port. A leaking side portis not uncommon. In case ofany doubt, a suture is alwayspreferable for the safety of theeye.
CapsulorhexisRhexis is the incision on
the lens capsule. If the cata-ract is big, a bigger rhexismust be done. Before rhexis,if the whole internal incisionis made, there is freemanoeuverity of the needlecystitome. In case of smallrhexis, two releasing inci-sions are to be given at 2 and10 o'clock position. Can-opener capsulotomy worksperfectly fine, but one has tobe careful duringhydroprocedures. Capsulo-rhexis should be the ultimategoal of incision on lens cap-sule for all surgeons. Apartfrom the placement of the lens'in-the-bag', it saves us frommany postoperative prob-lems.
Hydro ProcedureDebulk some of the vis-
coelastic substances from theanterior chamber to accom-modate fluid in the bag. Pressthe nucleus to release the
C autery
a
b
c
Fig 3: a) Line of dissection b) Triangular flap c) After completion of surgery
Fig 4: Types of incisions: a) Straight, b) Frown and c) Chevron.
CURRENT PRACTICE
57August, 2003 DOS Times - Vol.9, No.2
pent up fluid. See the fluidwave. Repeat hydro-dissection procedure in 3 to4 places. Hydro-delamina-tion is not at all necessary. Itmay create more problems toremove epinucleus.
Hydroprolapsing thenucleus into A/C
Drag the nucleus until theedge shows in front of therhexis margin. Press down atone end and lift the otheredge. Dial in clockwise oranti-clockwise direction toprolapse the whole nucleusinto the anterior chamber. Si-multaneous irrigation is nec-essary at this stage. Some-times, nucleus prolapse canbe achieved by a round hook.
It is advisable not to struggleduring nuclear prolapse.Most of the time, zonular de-hiscence occurs during thisstep. A small rhexis is themost important cause for this.Two relaxing incisions cansolve the problem very easily.
Nucleus delivery byirrigating vectis
The irrigating vectis canbe used directly via theRinger's Lactate tubing sys-tem or it can be fitted with a 5cc syringe filled with Ringer'sLactate solution. It's a matterof practice.
In this mechanism, themain forces behind nucleusdelivery by irrigating vectisare: (Fig: 8)
CURRENT PRACTICESteps of Surgery in Manual SICS by Irrigating Vectis
Photo 1: Conjunctival Flap Photo 2: External incision Photo 3: Internal incision Photo 4: Scleral pocket
Photo 5: Capsulorhexis Photo 6: Hydrodissection Photo 7: Nuclear prolapse Photo 8: Nucleus delivery
Photo 9: Nucleus delivery Photo 10: Cortical cleaning Photo 11: PC IOL in-the-bag Photo 12: Wound closure
1. Mechanical pull by the ir-rigating vectis.
2. Internal hydrostatic pres-sure.
3. Posterior lip depressionby the vectis. (Remember,if we lift the anterior lipwe close the wound, but ifwe press the posterior lipwe open the wound.)
4. Scleral stretching by thenucleus.
5. Counter balancing forceforwards and down-wards by the superior rec-tus bridle suture or epis-cleral forceps.
Cortical CleaningIf the hydrodissection is
perfect, cortical cleaning iseasy. From a rhexis it is
easier. Gentle flushing of theendothelial surface to cleanadherent tit-bits of corticalremnant with viscoelasticsludge at this stage helps ingood visibility. It is better notto chase for sub-incisionalcortex to remove all parts ofit. It is always wise to attemptmaximum cleaning of sub-incisional cortex after place-ment of IOL. Fine cortical fi-bres are best cleaned by jet offluid injected by a narrowcanula.
IOL PlacementIt is preferable to place the
IOL after inflating the bagwith viscoelastics. Only im-portant point is to clean thetunnel thoroughly before in-
58August, 2003 DOS Times - Vol.9, No.2
troducing the IOL throughthe tunnel. Otherwise, some-times blood clot or lens corti-cal particles may go insidealong with the lens andcleaning them is difficult.
Removal of Viscoelasticsfrom the Bag and AC
It is mandatory to clean allviscoelastic materials fromthe anterior chamber andfrom the bag. Through a largerhexis it is very easy to gobehind the IOL optic. Alter-nately, gentle tapping withthe I/A canula helps to clearmost of the viscoelastics fromthe bag.
Tunnel washingIt is one of the steps we
have learnt by experience.After completion of the sur-gery thorough tunnel wash-ing by Ringer's Lactate solu-tion using a hydrodissection
canula is very very important.If the scleral pockets are made,they are also to be cleaned. Tous, this is one of the majorcauses of prolonged postop-erative uveitis in some cases.It also cause delayed woundhealing that means, less sta-bilization of astigmatism.
SuturingSuturing is required in rare
circumstances. It is given byinfinity suture. For a largeincision even if the wound isself-sealing, it is given to re-duce the sagging of the poste-rior flap of the tunnel andthereby to reduce the astigma-tism. Of course, if the surgeonhas any doubt regarding theintegrity of the wound, it isbetter to place an infinity su-ture.
Role of Viscoelastic sub-stances in this method
Manual SICS by irrigating
CURRENT PRACTICE
Fig 5: Scleral pockets give more space to accommodate thicknucleus. Fig 6: Internal incision: Curved Vs. Straight
a) Parallel entry b) Oblique entryFig 7: Internal incision must be parallel to the external incision.
M echa n ica l d irect ion by th e Vec tis
Sc lera l s tretch in g
C o unte r ba la nce by forceps/ S R su tu re
In terna l hyd rosta tic
p ressure P o ster ior l ip depress ion
Sc lera l s tretch in g
Fig 8: Mechanism of nucleus delivery by irrigating vectis.
vectis needs adequateamount of viscoelastics inmany steps:
i) During Capsulorh-exis.
ii) During nucleusprolapsing.
iii) During Nucleusdelivery.
iv) Sometimes, duringcortical cleaning.
v) During IOL placement.vi) Even if the eye is soft at
the beginning, beforesclero-corneal tunnel-ing, via a side-port.
Choice of viscoelastics isalso important in some cases.High-quality dispersive vis-coelastic is essential in casesof suspected corneal endothe-lial problems, like cornealguttae or early Fuchs' dystro-phy. It provides an extra coat-ing to the corneal endothe-lium. Thus it gives an extra
protection to the corneal en-dothelium during thenucleus delivery.
ConclusionManual SICS has already
proved that it is the best alter-native surgical approach toinstrumental phacoemu-lsification as a cost effectivemethod for the developingcountries. This technique hasall the advantages ofstitchless cataract surgery interms of wider acceptance,greater wound stability, ear-lier visual rehabilitation, andgreater patient's as well assurgeon's comfort. A skilledand experienced SICS sur-geon can perform high qual-ity and high volume cataractsurgery at a lower cost at anypoint of time as compared toan experienced phaco sur-geon. It is really an urgentneed for our country.
59August, 2003 DOS Times - Vol.9, No.2
Choroidal neovascularmembranes (CNV) are aber-rant vessels that arise fromthe choriocapillaris, pen-etrate Bruch's membraneand proliferate between thethickened inner aspect andthe remainder of Bruch'smembrane and/or in thesub-retinal pigment epithe-lium and/or in the sub-reti-nal space.
Three important causes offormation of CNV are AgeRelated Macular Dege-
nerarion, Ocular Histoplas-mosis and Idiopathic cho-rodal neovascular mem-brane. Other causes beingPathologic myopia, AngiodStreaks, Multifocal Choroidi-tis, Serpiginious Choroiditis,Choroidal ruprure (Post trau-matic) etc.
Patients with CNV gener-ally complain of blurring ordecrease in vision, metamor-phopsia, micropsia, relativescotomas and rarely pho-
Transpupillary Thermo Therapy – An emergingmodality in treatment of Subfoveal andJuxtafoveal Choroidal Neovascular Membranes1Lalit Verma MD, 2Ankur Sinha (MD), 2Jayaram MD, 2H.K. Tiwari MD
topsia. Ophthalmoscopi-cally, subretinal fluid,subretinal hemorrhage,subretinal lipid, cystic retinaledema or thickening, or adirty grey-green subretinallesion gives clues to the pres-ence of a choroidal neovas-cular membrane. The exami-nation of the fellow eye ofsuch patients may also helpin diagnosis of the cause. Incase of ARMD the fellow eyemay have drusen (hard, soft,confluent, calcified etc.), dis-
ciform scar, pigmentary al-terations, CNV etc. "Histospots" are seen in a patientof ocular histoplasmosis.
Graph 1.Mean Best Corrected Letter Visual Acuity
35.36
39.24
36.8837.137.14
33
34
35
36
37
38
39
40
0 wks 4 wks 12 wks 24 wks 36 wksDuration
Lette
r vi
sual
acu
ity
7
54
3
98
7
0123456789
No
. of e
yes
< -1
5
< -5
,>=-1
5>=
-5 0<=
5
>5,<
=15
>15
Graph 2. Change in Letter Visual acuity score at 36 weeks
N o c h a n g e
D ec reas e in v isu a l acu i ty
I n c rea s e in v isu a l ac u i ty
Myopic changes in the fun-dus may point towards theetiology of the CNV. Angiodstreaks have bilateral presen-tation. Irregular, often radialPigmentary streaks/ linesaround the disc are typicalof angiod streaks. Patches ofChoroidits are seen in pa-tients having CNV second-ary to it.
ARMD is one of the majorcauses of CNV and 90% ofvisual loss in cases of ARMDis because of wet form of thedisesase.
(In a patient with agemore than 50 years present-
ing with the above men-tioned symptoms and asubretinal hemorrhage, oneshould rule out CNV second-ary to ARMD.)
Various treatment modalitiestried in CNV areØ Argon / Krypton laser
photocoagulationØ Trans scleral diode laserØ Interferon alpha 2aØ Radiation therapy (Tele-
therapy or Brachytherapy)Ø ThalidomideØ Transpupillary Thermo
Therapy (TTT)Ø Photodynamic Therapy
(PDT)
1. Vitreo-Retina Service, ApolloHospital & Centre for Sight,New Delhi2. Dr. R.P. Centre for OphthalmicSciences, AIIMS, Ansari Nagar,New Delhi - 110029
CURRENT PRACTICE
Three important causes of formation ofCNV are Age Related Macular
Degenerarion, Ocular Histoplasmosisand Idiopathic choroidal neovascular
membrane
Ophthalmoscopically, subretinal fluid,subretinal hemorrhage, subretinal lipid,cystic retinal edema or thickening, or adirty grey-green subretinal lesion gives
clues to the presence of a choroidalneovascular membrane
60August, 2003 DOS Times - Vol.9, No.2
and shown variable re-sults.Subretial Surgery trialsconcluded that there isno reason to prefersubmacular surgery tolaser photocoagulation.
Classification of CNVØTopographic classifi-cationl Extrafoveall Juxtafoveall SubfovealØAngiographic classi-ficationl Classicl Occult
Treatment options de-pending upon the topo-graphic location of theCNVExtrafoveal CNV- La-
ser photocoagulationwith 532 nm is still thefirst line of managementin such lesions, al-though the problems ofrecurrence and persis-tence are there.Subfoveal CNV - Laser
photocoagulation hasbeen shown to be effec-tive, but frought withthe problems of imme-diate fall in vision.Juxtafoveal CNV -- Thedefinition of such le-
sions is vague, adequate la-ser photocoagulation is a dif-ficult proposition injuxtafoveal lesions, treatmentof juxtafoveal membranewith conventional laser isfraught with the problem ofimmediate fall of vision dueto direct effect of the laser orrun off phenomenon of laserreaction. Juxtafoveal lesionsare best treated as subfoveallesions, (personal opinion)however rarely laser photo-coagulation (532 nm) can be
Fig 1.Colour fundus photograph and FFA of 59 yearold male with subfoveal CNV, upper photo andFFA is Pre –TTT, lower 3 months post TTT, note thedecrease in the hyperfluorescence. The pre and postlaser visual acuity was stabilized (20 letters).
Fig 3. Pre TTT, 3 and 6 months post laser colourfundus photograph and FFA of 67 year old femalewith subfoveal CNV. Notice the partial resolutionof the CNV. The pre and post laser visual acuitywas 35 letters during the course of follow up.
Ø Macular rotation surgeryØ Subretinal surgery
Argon and Krypton laserphotocoagulation, althoughcontroversial is the onlyproven effective modality fordelaying severe visual loss(Macular PhotocoagulationStudy Group 1982 - 1995).
Transscleral diode laser,
has shown encouraging re-sults in an initial experience,but needs further evaluation(RPC study 2003).
Interferon alpha 2a: nobenefit of the treatment wasobserved in a randomizedplacebo controlled clinicaltrial (Pharmacologicaltherapy for macular degen-
eration study group 1994)Radiotherapy did not
show difference between pa-tients and controls in visualacuity at one year, hence nobenefit of the treatment (RADstudy)
Thalidomide, known toprevent growth of blood ves-sels when administeredorally in rabbits, its exact roleis not known.
Macular Rotation Sur-gery, various groups haveused different techniques
CURRENT PRACTICE
Fig 2.Colour fundus photograph and FFA of 80year old male with subfoveal CNV, upper photoand FFA is Pre –TTT ( letter acuity – 35), lower 3months post TTT ( letter acuity – 33), note the de-crease in the hyperfluorescence.
Fig 4.Colour fundus photograph and FFA of 62year old female with subfoveal CNV, upper photoand FFA is Pre –TTT, lower 3 months post TTT,note the decrease in the size and intensity of thehyperfluorescence. The pre and post laser visualacuity was 35 letters.
61August, 2003 DOS Times - Vol.9, No.2
Various parameters at each follow up following TTT in subfoveal CNV
Parameter Prelaser 4 weeks 12 weeks 24 weeks 36 weeks
Mean Letter visual acuity 35.36 39.24 37.14 37.1 36.88
Mean Scotoma Score 45.4 41.26 38.6 35.88 34.45
Mean Reading Ability 24.67 28.69 31.74 34.14 34.14
Various parameters at each follow up in patients of juxtafoveal CNV subjected to TTT
Follow up (weeks)___________________________________________
Parameter Prelaser 4 12 24 36 52
Mean Letter ARMD 48.43 52.93 50.5 47.71 52 50
visual acuity Idiopathic 52.13 59.13 61.88 64.71 59 52
Mean Contrast ARMD 1.04 1.13 1.13 1.07 1.16 1.13
threshold Idiopathic 0.86 0.88 1.09 1.11 1.15 1.28(log units)
Mean Reading ARMD 54.07 54.21 51.29 52.71 62 60
Ability(seconds) Idiopathic 68.5 65.12 62.25 71.57 74.67 41.5
done with prior explanationto the patient the risk of im-mediate fall in vision.
Two of the treatment mo-dalities have recentlygained importance, they areTTT and PDT
Photodynamic Therapy -Treatment of age relatedmacular degeneration with
CURRENT PRACTICE
photodynamic therapy(TAP) study group in 2002has shown that the stabili-zation of visual acuity (de-fined as ± 3 lines) was seenin 59% of the treated eyes ascompared to 31% in the pla-cebo group at 24 months fol-low up.
Transpupillary ThermoTherapy -- Transpupillary
thermotherapy (TTT) wasfirst termed by Oosterhuis etal. It is a technique by whichheat is delivered to the chor-oid and retinal pigment epi-thelium using a diode laserat 810nm. The goal in usingthis technique for treatmentof choroidal neovasculari-zation is to achieve occlu-sion of the neovasculari-zation without damage toother cells. Heat penetrationis optimized by exposuretime, beam diameter, andwavelength.
The exact mechanism of
action of TTT is still un-known, various mechanismsthought are apoptosis, ex-pression of heat shock pro-teins, free radical damage etc.
Thus the low temperatureTTT is a potential strategy fordecreasing neural damage.The aim of treatment is local-ized and controlled heatingof the choroidal neovascularmembrane to subphoto-coagulative temperature
Our Experience with TTTSubfoveal CNV
Forty three eyes of thirtynine patients were subjectedto TTT after an angiographicevidence of subfoveal chor-oidal neovascular membranesecondary to ARMD. Visualfunction outcome were mea-sured before and after TTT.The parameters were bestcorrected letter visual acuity,contrast threshold, readingability, scotoma and meta-morphopsia score (usingAmsler's Grid). The followup was for 4, 12, 24 and 36weeks after the laser.
Results are summarizedin the graphs 1 and 2, andfigures 1 to 4.
In our study of subfovealCNV, the Letter acuitystabilised or improved (moveof one line) in 71.4% at 9months follow up (P=0.034).Reading speed improved atall follow ups till 9 monthswhich was statistically sig-nificant (P=0. 017). Scotomascore decreased during 9months follow up (P=0.014),with all follow ups showingstatistically significant de-crease. Contrast sensitivityincreased during 9 monthsfollow up with statisticallysignificant increase at 12weeks (P=0.042).
Graph 3 .Mean Best Corrected Letter Visual Acuity
47.7152 5050.548.43
52.93
52
5964.7161.8859.13
52.13
2025303540455055606570
Prelas
er
4 wee
ks
12 wee
ks
24 wee
ks
36 wee
ks
52 wee
ks
Lett
er V
isua
l Acu
ity
AMD Idiopathic
0 0
2
0
2 2
0 0 0
1
1
2 22
0
0.5
1
1.5
2
No
. of E
yes
> -1
0
>-5,
<= -1
0
< = -
5 0<=
+5
>+5,
<=+1
0>+
10
Graph 4.Change in letter visual acuity at 12 weeks
AMD Idiopathic
ARMD is one of the major causesof CNV and 90% of visual loss incases of ARMD is because of wet
form of the disesase Contd. on page 96
62August, 2003 DOS Times - Vol.9, No.2
Attention D.O.S. MembersThe Hi-tech DOS Library has started functioning on Ground Floor, Dr. R.P. Centre, Delhi Ophthalmic
Sciences, AIIMS, New Delhi-110029 from 12.00 Noon to 9.00 P.M. on week days and 10.00 A.M. - 1.00P.M. on Saturday, Sunday. The Library will remain closed on Gazetted Holidays. Members are requestedto utilise the facilities available i.e. Computer, Video Viewing, Latest Books and Journals. We are plan-ning to subscribe two journals. Member can give suggestion in this regard.
Dr. Lalit VermaLibrary Officer, D.O.S.
List of Books and Journals Available in Library
DOS Library Book List1. An Atlas of Ophthalmic Trauma
Editors - Thomas C Spoor2. Manual of Fundus Fluorescein
AngiographyEditors - Amresh Chopdar
3. Complications of GlaucomaTherapyEditors - Mark B. Sherwood. M.D.George L. Spaeth M.D.
4. Corneal Topography the State ofthe ArtEditors - James P. Gills
5. Radial Keratotomy SurgicalTechniquesEditors - Donald R. Sanders M.D.PHD.
6. Refractive Corneal SurgeryEditors - Donald R. Sanders M.D.PHD; Robert F. Hofmann-MD;JamesJ. Salz-MD
7. Second Edition-Laser Surgery OfThe Posterior SegmentEditors - Steven M. Bloom AlexanderJ.Brucker
8. Sixth Edition - Becker-Shafeer R.S.Diagnosis and Therapy of theGlaucomasEditors - H. Dundar Hoskins Jr.-Michael Kass
9. Phacoemulsification New Technol-ogy and Clinical ApplicationEditors - I. Howard Fine
10. Textbook of AdvancedPhacoemulsification TechniquesEditors - Paul S. Koch. James-A-Davison
11. Ocular Differential DiagnosisEditors - Frede’rick Hampton Roy
12. Retinal Detachment A ColourManual of Diagnosis & TreatmentEditors - Jack J. Kanski
13. Current Concepts in OphthalmicLasersRajvaradhan Azad, H.K. Tewari
14. Converting toPhacoemulsification (ThirgdEdition)Making the Transition to in-the-Bag PhacoPaul S. Koch.
15. Mastering Phacoemulsification (Asimplified Manual of Strategies forthe Spring, Crack and Stop andChop Technique (Fourth Edition)Editors - Paul S. Koch
16. Ocular Infection Investigation andTreatment in PracticeEditors - Martin Dunitz
17. IOL and PhacoemulsificationSecretsEditors - V.K. Dada
18. Vitrectomy for BeginnersEditors - Rajvardhan Azad
19. Radial Keratotomy (Principles andPractice)Editors - Keiki R. Mehta
20. Radial KeratotomyEditors - Donald Sanders M.D.
21. Soft Implant Lenses in CataractSurgeryEditors - Thomas R. Mazzocco MD.George M. Rajacich MD.Edward Epstein M.D.
22. Computerized Perimetry A.Simplified Guide(Second Edition) Editors - Mar L.F.Lieberman Michael V. Drake
23. Fun with PhacoEditors - V.K. Dada
24. Practical Atlas of Retinal Diseaseand TherapyEditors - William R. Freeman
25. Retina and Vitreous Text Book ofOphthalmologyEditors - Steven M. Podos and MyronYanoff
26. A Practical Manual of IndirectOphthalmoscopyEditors - Rajvardhan Azad H.K.
Tewari27. Phacodynamics Mastering the
Tools and Techniques ofPhacoemulsification Surgery(Second Edition)Editors Barry S. Seibal
28. Techniques of PhacoemulsificationSurgery Intraocular Lens Implanta-tionEditors - Moshe Yalon
29. Cataract Surgery and its Complica-tions (Sixth Edition)Editors - S. Jaffe
30. A Colour Atlas of Lens Implanta-tionEditors - Piers Percival
31. Cataract and IOLEditors - D. Singh R. Singh J. WorstR. Singh
DOS Library Journal List1. Survey of Ophthalmology
Vol.44 No.3 November-December-99.2. Survey of Ophthalmology
Vol.44 Supplement 1. October-993. Survey of Ophthalmology
Vol.44 No.2 September-October-99.4. Survey of Ophthalmology
Vol.43 No.6 May-June-995. Survey of Ophthalmology
Vol.43 No.6 May-June-996. Ophthalmology Clinics of North
AmericaOcular Infections: Update onTherapyEditor - Terrence-P-O Brien M.D.
7. Ophthalmology Clinics of NorthAmericaSports and Industrial OphthEditor Louis D. Pizzarello MD-Mphand Michael Easterbook MD
8. Ophthalmology Clinics of NorthAmericaOcular OncologyEditor Joan M.O. Brien MD
LIBRARY
63August, 2003 DOS Times - Vol.9, No.2
DOS Library Books1. Update On General Medicine (Ameri-
can Academy Ophthalmology)2. Fundamentals & Principles Of Oph-
thalmology (American AcademyOphthalmology)
3. Optics Refraction & Contact Lenses(American Academy Ophthalmol-ogy)
4. Ophthalmic Pathology & IntraocularTumors (American Academy Oph-thalmology)
5. Neuro Ophthalmology (AmericanAcademy Ophthalmology)
6. Pediatric Ophthalmology & Strabis-mus (American Academy Ophthal-mology)
7. Orbit Eyelids & Lacrimal System(American Academy Ophthalmol-ogy)
8. External Disease & Cornea (Ameri-can Academy Ophthalmology)
9. Intraocular Inflammation And Uvei-tis (American Academy Ophthalmol-ogy)
10. Glaucoma (American Academy Oph-thalmology)
11. Lens And Cataract (American Acad-emy Ophthalmology)
12. Retina And Vitreous (AmericanAcademy Ophthalmology)
13. (1-12 Master I Ndex (American Acad-emy Ophthalmology)
14. The Cornea (Third Edition) – (GilbertSmolin, Ricard)
15. Principales And Practice Of Refrac-tive Surgery- (Elander, Rich, Robin)
16. The Glaucomas Clinical Science (Sec-ond Edition) – (715-1372 Ritch,
Schields, Krupin)17. The Glaucomas, Basic Sciences
(Sedond Edition) - (1-714 Ritch,Schields, Krupin)
18. The Glaucomas Glaucomas Therapy(Second Edition) - 1373-1807 Ritch,Schields, Krupin)
19. Ophthalmic Plastic And Reconstruc-tive Surgery (Second Edition) - Nesi,Lismanlevine
20. Practical Orthoptics In The Treat-ment Of Squint (Fifth Edition) - LyleAnd Jackson. S
21. Binocular Vision And OcularMontility (Fifth Edition) - Von.Noorden
22. Principles And Practice Of Ophthal-mology (Vol - 1 Second Edition) -Albert, Jakobiec.Azar
23. Principles And Practice Of Ophthal-mology (Vol - 2 Second Edition) -Albert, Jakobiec.Azar
24. Principles And Practice Of Ophthal-mology (Vol - 3 Second Edition) -Albert, Jakobiec.Azar
25. Principles And Practice Of Ophthal-mology (Vol - 4 Second Edition) -Albert, Jakobiec.Azar
26. Principles And Practice Of Ophthal-mology (Vol - 5 Second Edition) -Albert, Jakobiec.Azar
27. Principles And Practice Of Ophthal-mology (Vol - 6 Second Edition) -Albert, Jakobiec.Azar
28. Handbook Of Lasik Surgery -Vajpayee, T.Dada, R. Snibson
29. Community Ophthalmology - P.K.Khosla
30. Community Ophthalmology - P.K.
Khosla31. Fluorescein Angiography - A Users
Manual - H.K. Tewari, Lalit Verma,Pradeep Venkatesh
32. Text Book of Ocular Therapeutics –Ashok Garg
DOS Library Journals1. Ocular Surgery For The New Millen-
nium (Part II - March 2000. 13:1) Oph-thalmology Clinics Of North America- Editor Gergel. Spaeth. Md)
2. Information Technology In Ophthal-mology (June 2000 13:2) Ophthalmol-ogy Clinics Of North America - Edi-tor Leonard Goldschmidt)
3. Ocular Surgery For The New Millen-nium Part I (Dec 1999 12:4) Ophthal-mology Clinics Of North America -Georgel Spath. Md)
4. Retinal Vascular Disorders (Dec 199811:4) (Ophthalmology Clinics OfNorth America (Dr. Pran N. Nagpal- Donated By Dr. B. Patnaik)
5. Survey Of Ophthalmology (Vol 44No.4 Jan-Feb 2000)
6. Survey Of Ophthalmology (Vol 44No.5 March-April 2000)
7. Survey Of Ophthalmology (Vol 44No.6 May-Jul 2000)
8. Survey Of Ophthalmology (Vol 45No.1 July-August 2000)
9. International Ophthalmology (Vol 23No.1 Pp-1-60 1999)
10. Retina The Journal Of Retinal AndVitreous Diseases (Vol 20 No.1 2000)
11. Journal Of Cataract Refractive Sur-gery (Vol 26 No.8 August 2000)
List of Books and Journals (New Arrivals) in Library
Nx = Highest attendance of all meetings
N = Total number of delegates
n = Total number of internal delegates
Methodology for Monthly Clinical Meeting:Criteria for Selection
Formula: Institution's MarksAttendance of institution (N)
Average marks A (outside delegates) x 0.7 + ——————————————————————— x 3maximum attendance in any monthly meeting (Nx)
Total marks by outside delegates (M)A = ————————————————————
Total number of outside delegates (N-n)
N = Total Attendance of an instituton(Outside + internal delegates)
LIBRARY
64August, 2003 DOS Times - Vol.9, No.2
Aging eye or the PRESBY-OPIC EYE refers to slow, nor-mal and age related irrevers-ible reduction in magnitudeof accommodative ampli-tude. i. e there is recession innear point. Comfortable nearvision prevails till theamount of accommodationemployed is less than onehalf the total amplitude of ac-commodation.
Presbyopia usually sets inaround the age of 40. The am-plitude of accommodationdrops to less than 5 by thisage.The required amplitudeat usual working distance is2.5 Diopters ( 100 cm/40cm)so the required amplitudemay drop to less than half.Presbyopia can be reportedanywhere between 38 to 48years of age depending onthe working conditions andrefractive error. A hyperme-tropic eye reports Presbyopiaearlier then myopic eye.
The recession in nearpoint is sufficient to causediscomfort or asthenopicsymptoms at customary nearworking distance. Some on-set complaints are
Blurring of vision at nearworking distance
Drowsiness after shortperiod of reading
Holds book away to readTransient diplopia on
near workAccommodative spasm or
pseudomyopia
Prescribing the Aging Eye– The Presbyopic CorrectionMonica Chaudhary
Dr. R.P. Centre for OphthalmicSciences, AIIMS, Ansari Nagar,New Delhi - 110029
Near vision charts are usedto detect reduction in near vi-sual acuity. Patient reads thechart at 40 cms and thesmallest print read is re-corded. The near visioncharts do not measure thenear vision but the near vi-sion adequacy. The maximumreading efficiency is whenthe print size is 3 times thesize of the smallest print read.A non presbyopic patientwill read 0.4 M or J1 or N6equivalent to 6/6 at 40 cmsdistance.
The correction is in theform of addition over the dis-tance correction .It is impor-tant that the addition deter-mination is based on Age andthe Patients unique workingdistance.
Addition Determinationcan be done by followingmethods in routine
Age basedMeasuring the amplitude
of accommodation
The AgeSince amplitude of accom-
modation is age dependentthe presbyopic addition canbe estimated arbitrarily basedon patients age .The estima-tions are strictly the startingpoint and do not adjust forparticular demands.
A table by Hofstetter’s ageand amplitude values is agood guide as starting pointand then modify near rangeaccording to patients needs.
After the add is deter-mined the range is tested, that
is move the chart further andcloser reading the smallestline visible. This rangeshould coincide with the re-quired working distance andrecorded as closest /clearest/farthest point in cmfor eg. 20cm/40cm/67cm.
If the patient desires nearrange away reduce by 0.25 Dsteps and if closer range isdesired then increase in0.25D steps.
Presbyopic correctionbased on Amplitude ofaccommodation
To measure the amplitudethe easiest method isDonder’s or Duane’smethod. The patient readsthe near vision chart (thesmallest line visible) and thechart is brought closer till theprint blurs. This punctumproximum is converted indiopters ( e g 20cm = 100/20= 5 Diopters.)This test is pref-erably done binocularly. Er-ror may arise if larger printis used. Near point ruler canalso be used for measure-ment.
Sheard’s method alsomeasures amplitude of ac-commodation. The near vi-sion chart is held at 40cmsand patient reads smallestprint and minus lenses areadded uniocularly till blur.This measures the Amplitudeof accommodation.
Based on Amplitude theADD is calculated. Deter-mine NPA . Suppose it is50cms.The Amplitude of ac-
commodation is 2 DioptersKeep 1/3rd in reserve forcomfort so the available ac-commodation is 1.33 .If thepatient desires to readat33cms.He needs 3.0 diopt-ers .Thus the extra add re-quired is 3 - 1.33 i. e 1.67 Di-opters.
Trouble shooters in pre-scribing adds
Caution – Don’t add toomuch plus it not only con-stricts near range but alsomakes the patient accus-tomed to higher magnifica-tion and will always desireextra add.
A beginner may never besure of his working distance.
In case of previous wearerjudge the deficit on basis ofwhat he is using and the com-plaint with it.
A tall person habituallyholds the book away to read,so may require lesser addi-tion to have comfortablerange further away .
Habitual higher add us-ers may be difficult to reduceTrial to reduce additions isdone gradually. Such prob-lem is common in our coun-try where over the counterglasses are frequently pur-chased.
Patients with nuclearcataracts shift towards myo-pia for distance They areused to higher plus for nearand may not accept reducedadditions.
Presbyopic correction in anuncorrected hyperopia
A hypermetrope are usu-ally pre presbyopes and de-velop blur and asthenopiasoon.. Vision is intermit-tently affected as the accom-modation reserves start tofail. The best way to correct
ART OF REFRACTION
65August, 2003 DOS Times - Vol.9, No.2
such patients is to refractunder cycloplegia and thencalculate the add over itMany times for beginners adistance correction usedmainly for near work is bestprescribed .As the patientadapts looking through thedistance vision for distancewill also adjust. If the patientis asymptomatic there is noneed of prescription.
Myopes and presbyopiaLow Myopes may be fussy
over wearing Bifocals. Somemay never accept readingadditions and prefer readingwithout glasses at the focalpoint. If satisfied and asymp-tomatic agree to readingwithout glasses. High My-opes (>-8) may have subnor-mal visual acuity due topathological damage toretina, a higher plus addi-tion may be given to increasemagnification. This maylimit working distancewhich has to be explained.
Astigmatic PresbyopeAccurate spherical and cy-
lindrical power has to be de-termined Any change inspherical component effectsdetermination of add. Someastigmatic patients may notbe comfortable with bifocalsbecause the axis of bifocals isnot same for near due to eyes
undergoing excyclovergence.This is minimal for small cyl-inders and considerable forlarge cylinders (> 2D). The so-lution is to assess and find arepositioned cylinder axis atthe true reading position bin-ocularly and advice separateglasses for reading.
Presbyopia andAnisometropia
We do binocular near cor-rection in routine but there isno reason to believe that theaccommodation demand fornear for 2 eyes will be samefor near. The myopic eye fullycorrected for distance accom-modates less than a hyper-metropic eye. So there may benumber of situations whenunequal additions has to begiven to avoid, unpleasantsituations where patient re-turns with complaint of oneeye clear at close and othereye clear away.
If one eye has low visionand there is no binocularitycorrect the better eye and givebalance add in the weakereye.
Addition in aphakes andpseudophakes The accom-modative function is zeroand the expected addition is3.0 Diopters for reading at33cms.If the vision is 6/6 andreading is desired at 50 cmsthe addition has to +2.0
Dsph. If the best correctedvision < 6/6 higher additionhas to be given to let the pa-tient read newsprint. Thiswill reduce his working dis-tance.
An binocular aphake canbe advised to slide away hisdistance glasses, so that ef-fective power can be in-creased and reading madepossible for short times andfrequent change to readingglasses avoided.
Bifocals are now availablefor aphakes in plastic andaspheric design which cansolve problem of carrying 2glasses. Such bifocals are es-sential for children who arewearing aphakic glassesabove the age of 3 years.
Recommend proper orstrong lighting to elderly tocompensate for the lost con-trast sensitivity.
Types of lenses used for cor-rection of presbyopes
Separate reading glassesBifocalsTrifocalsMultifocals or progressi-vesBifocals we all know of
are of various types bothavailable in glass and plas-tic. The original round seg-ment Kryptok is relatively in-visible. The D type of bifocalhas an advantage of less im-age jump so better accepted.The straight top executivehas advantage of large nearsegment ,less image jump butlooses its popularity due topoor cosmesis. Patients withlesser adds (,1.0D) may notbe comfortable with bifocals.Most bifocals styles availablehave add segments upto 3.5Diopters.
Some practical instruc-tions for bifocal adaptation
areHead should be straight
ahead for distance viewingWhile climbing stairs
warn to look through dis-tance segment
Keep reading materialclose to body
For reading rotate eyesand not head.
Read at the working dis-tance calculated. go closer forhigher adds.
Trifocals have an interme-diate add for the intermedi-ate distance and the interme-diate add is automaticallycalculated as half of the read-ing addition.
Trifocals are outdatednowadays as Progressiveshave taken over.
Multifocals progressivesor PAL have continuouspower change from distanceto near add .They are avail-able in various designs –Hard and Soft. The design isshown in the diagram. Theselenses are best for patientswho need all range of nearworking distances like thecomputer professionals.Progressives are difficult toadapt initially but providenear vision quite near the nor-mal non – presbyopic patient.
Another option forpresbyopes is Contact lens.Most of our patients whostarted wearing lenses 15years back are now shiftingto presbyopic age and are notwilling to accept glasses. Forsuch patients Monovisionconcept of contact lens fittingis used that is to correct oneeye for distance and othereye for reading. Also bifocalContact lenses are gettingpopular and freely availableto patients who want to wearcontact lens at presbyopicage.
ART OF REFRACTION
!!Attention DOS Members!!
The last date of acceptance of applicationfor “DOS Fellowship for Partial
Assistance to Attend Conference” hasbeen extended to 20th August, 2003instead of 31st July, 2003. The new
application format is being published inthis issue (see page 92)
66August, 2003 DOS Times - Vol.9, No.2
Intraoperative arcuate transversekeratotomy with phacoemulsificationeffectively decreases pre-existingastigmatismTitiyal JS, Baidya KP, Sinha R, Ray M, Sharma N,Vajpayee RB, Dada VK.Rajendra Prasad Centre for Ophthalmic Sciences, All IndiaInstitute of Ophthalmic Sciences, New Delhi, [email protected]
The authors evaluated the efficacy of paired intraoperativearcuate transverse keratotomy at a 7-mm-diameter zone alongwith a 3.5-mm clear corneal phaco tunnel in the steeper axisto correct pre-existing astigmatism.
This prospective randomized case-control study was con-ducted on 34 eyes of 28 patients with immature senile cata-ract. They were divided into two groups; in one group (17eyes) intraoperative arcuate keratotomy was coupled withphacoemulsification in the steeper meridian (arcuate kera-totomy group; mean preoperative astigmatism 2.28 +/- 0.89D) and the other group (17 eyes) phacoemulsification wasperformed in the steeper meridian without arcuate kerato-tomy (control group; mean preoperative astigmatism 2.04+/- 0.50 D). The patients were examined at 1 day, and 1, 4,and 8 weeks postoperatively. Correction of keratometric astig-matism, surgically induced refractive changes, magnitudeand axis of cylinder, spherical equivalent refraction, withand against the wound change, and coupling ratio wereevaluated. RESULTS: Mean reduction in keratometric astig-matism in the keratotomy group was 1.26 +/- 0.54 D (P =.0067) and in the control group was 0.48 +/- 0.60 D (P =.0423). The difference in reduction of keratometric astigma-tism between the two groups was statistically significant (P= .0296). Surgically induced refractive change at 8 weeksfollow-up was 2.15 +/- 1.13 D in the keratotomy group and1.50 +/- 1.32 D in the control group (P = .046). Coupling ratiowas -1.10 +/- 0.43 in the keratotomy group at 8 weeks aftersurgery while the control group was -0.82 +/- 0.38.
The conclusion was combination of intraoperative arcu-ate keratotomy with steep axis phacoemulsification incisionis more effective than steep axis phacoemulsification inci-sion alone in reducing pre-existing astigmatism.
v v v
Large-spot size transpupillarythermotherapy is effective instabilizing the visual acuity in thosepatients who have occult choroidalneovascularization due to age-related
JOURNAL ABSTRACTS
macular degenerationThach AB, Sipperley JO, Dugel PU, Sneed SR, ParkDW, Cornelius J.Retinal Consultants of Arizona, Phoenix 85064, USA.
Authors described the outcome of patients with occult chor-oidal neovascularization in age-related macular degenera-tion treated with transpupillary thermotherapy. In a pro-spective, nonrandomized, nonmasked case series.
All patients with age-related macular degeneration witha predominantly occult choroidal neovascular membraneand an initial visual acuity of 20/400 or better were offeredtreatment using transpupillary thermotherapy. The treat-ment consisted of using a diode laser, a spot size of about3000 to 6000 micro m delivered over 60 seconds, and a powerof 600 to 1000 mW.Main Outcome Measures: A stable, im-proved, or worsened visual acuity and the need for addi-tional treatment.
Results showed in all sixty-nine patients were treated.All patients have been followed up for at least 6 months. Atthe 6-, 9-, and 12-month follow-up visits, 71% of patientshave stable or improved visual acuity and 29% have lost 2 ormore lines of visual acuity on the Snellen letter chart.
Large-spot size transpupillary thermotherapy is effectivein stabilizing the visual acuity in those patients who haveoccult choroidal neovascularization due to age-related macu-lar degeneration.
v v v
Optical coherence tomography allowsdiagnosis of subtle vitreomaculartraction and provided precisepreoperative and postoperativeassessments of macular thicknessMassin P, Duguid G, Erginay A, Haouchine B,Gaudric A.Department of Ophthalmology, Hopital Lariboisiere, Assis-tance Publique-Hopitaux de Paris, Universite Paris 7, Paris,France. [email protected]
The authors report the use of optical coherence tomography(OCT) for evaluation of diffuse diabetic macular edema(DME) before and after vitrectomy. DESIGN: Interventionalcase series.
A retrospective study was made of 15 consecutive eyes of13 patients that had vitrectomy for diffuse DME and OCTpreoperatively and postoperatively. In seven eyes of six pa-tients (group 1), vitrectomy was performed because ofvitreomacular traction observed on biomicroscopy or OCT.In the other eight eyes of seven patients (group 2), vitrectomywas performed for DME not responsive to laser photocoagu-
67August, 2003 DOS Times - Vol.9, No.2
lation, with no vitreomacular traction on biomicroscopy orOCT.
In results mean +/- standard deviation (SD) follow-upafter vitrectomy was 18 +/- 10 months (range, 6 to 33 months).In group 1, mean +/- SD retinal thickness decreased signifi-cantly from 661 +/- 181 microm preoperatively to 210 +/- 32microm at the end of follow-up (P =.018). Median best-cor-rected visual acuity (BCVA) improved from 20/100 beforesurgery (range, 20/250 to 20/50) to 20/80 at the end of fol-low-up (range, 20/250 to 20/25; P =.046). In one eye in group1, vitreomacular traction was only observed on OCT and noton biomicroscopy. In group 2, mean +/- SD retinal thicknessdecreased from 522 +/- 103 microm preoperatively to 428+/- 121 microm at the end of follow-up (P =.2). Median BCVAwas 20/100 before vitrectomy (range, 20/320 to 20/63) and20/200 at the end of follow-up (range, 20/250 to 20/63; P=.78).
In conclusion vitrectomy was beneficial in eyes with dif-fuse DME combined with vitreomacular traction but not in eyes without traction. Optical coherence tomography al-lowed diagnosis of subtle vitreomacular traction and pro-vided precise preoperative and postoperative assessmentsof macular thickness.
v v v
C(3)F(8) gas is more effective tampon-ade than silicone oil with respect toachieving initial closure of macularholes. Final visual acuity is better forgas-operated eyes than for silicone-operated eyesLai JC, Stinnett SS, McCuen BW.Department of Ophthalmology, Duke Eye Center, Duke Uni-
versity Medical Center, Durham, North Carolina, USA.
Authors compared anatomic and functional outcomes ofmacular hole surgery with either silicone oil or C(3)F(8) gastamponade. In a retrospective comparative interventionalstudy.
Fifty-four eyes of 51 patients underwent pars planavitrectomy for macular holes. Thirty-one eyes were treatedwith silicone oil tamponade, and 23 eyes were treated withC(3)F(8) tamponade.
Demographics, preoperative and postoperative charac-teristics, and complications were analyzed.
Main outcome measures were preoperative and postop-erative visual acuity, initial hole closure, number of persis-tent or recurrent holes, number of reoperations, and finalhole closure.
Results showed the silicone oil and gas tamponadegroups were demographically similar. The rate of hole clo-sure after one operation with oil tamponade was signifi-cantly lower than that with gas tamponade (65% vs. 91%; P= 0.022). The percentage of patients undergoing a secondoperation was significantly higher in the oil group (35% vs.4%; P = 0.006). However, with reoperations, the final rate ofhole closure was similar between the oil and gas groups(90% vs. 96%; P = 0.628). The final median visual acuity forthe gas group was significantly better than for the oil group(20/50 vs. 20/70; P = 0.047).
In conclusion C(3)F(8) gas proved to be a more effectivetamponade than silicone oil with respect to achieving initialclosure of macular holes. Eyes receiving an oil tamponaderequired significantly more reoperations to achieve a simi-lar rate of hole closure compared with eyes undergoing agas tamponade. Final visual acuity was better for gas-oper-ated eyes than for silicone-operated eyes.
v v v
JOURNAL ABSTRACTS
High Lights for September Issue of DOS Times
Ø Management of Fungal & Acanthamoeba Keratitis : Dr. M. Srinivasan
Ø Management of Non-healing Corneal Ulcer : Dr. R.N. Bhatnagar
Ø Lamellar Keratoplasty: Current Prespective : Dr. J.S. Titiyal
Ø Difficulties and Complications of SICS : Dr. K.P.S. Malik
Ø Botulinum Toxin A Injection for Blepherospasm : Dr. Madhu Karna
Ø Retinoblastoma : Dr. Anita Sethi
Ø Surgical Management of Pediatric Cataract : Dr. Abhay Vasavada
68August, 2003 DOS Times - Vol.9, No.2
The rate of technological and academic obsolescencein Ophthalmology has reached astronomical levels inrecent times. What was advanced yesterday may al-ready be obsolete today. The rapid strides in skills andknowledge have created a need for an extremely inten-sive Continuing Medical Education programme.
DOS has always been in the forefront of efforts toensure that its members remain abreast with the latestdevelopments in Ophthalmology. Among the impor-tant objectives formulated by the founders of our con-
DOS Credit Rating System (DCRS)
If any of the presentations is given an Award –Additional 20 bonus Credits.
Member who have earned 100 Credits, are enti-tled to:
a) Certificate of Academic Excellence in Ophthal-mic Practice.
b) 50% exemption of Registration fee at next An-nual DOS Conference.
c) Certificate of Academic Excellence in Ophthal-mic Practice (3 years in row) will entitle the mem-ber to a proposed academic grant of Rs.5,000/- onlyto enable him/her to attend any international con-ference outside India to present his/her own ac-cepted presentation (proof required).
If any member earns 200 Credits, he/she shall,in addition to above, be awarded Certificate of Dis-tinguished Resource-Teacher of the Society.
stitution was the cultivation and promotion of the Sci-ence of Ophthalmology in Delhi.
In a bid to strengthen our efforts in this direction andfulfil the vision of our society’s founders, DOS announcesthe DOS Credit Rating System (DCRS), the details ofwhich are given below. Our Primary objective is topromote value-based knowledge and skills in Ophthal-mology for our members and give recognition and creditfor efforts made by individual members to achieve stand-ards of academic excellence in Ophthalmic Practice.
DOS announces a new era in Continuing Medical EducationDOS CREDIT RATING SYSTEM (DCRS)
(A new chapter in CME)Credits
1) Attending Monthly Clinical Meeting* † (For full attendence) 10
2) Making Case Presentation at Monthly Meeting** 15
3) Delivering a Clinical Talk at Monthly Meeting** 15
4) Free Paper Presentation at Annual Conference (To Presenter)** 15
5) Speaker/Instructor** in : Monthly Symposium 15
: Mid Term Symposium 15
: Annual Conference 15
6) Registered Delegate at Mid Term DOS Conference 20
7) Registered Delegate at Annual DOS Conference 30
8) Full Article publication in Delhi Journal of Ophthalmology (Visiscan) 15
9) Letter to Editor/Correspondence/Published Article in DOS Times 10——————————————————————————————————————————————
Institutional assessment for best performancewill be based on the total score of members whoattend divided by number of members who at-tended. Institutional assessment regarding deci-sion to retain the institute for the next year will bebased on total score by all delegates who attendthe meeting divided by average attendence of all8 meetings.
Please note that the Institutions’ grading in-creases if the attendance at its meeting is higher(i.e. more than the average attendence of the eightmonthly meetings).——————————————————————* Based on Signature in DCAC** Subject to Submission of Full Text to Secretary, DOS† Credits will be reduced in case attendence is only forpart of the meeting.
DCRS
69August, 2003 DOS Times - Vol.9, No.2
ConferencesInternational: two fellowships per yearl Maximum of Rs. 25,000/-will be sanctioned
National: three fellowships per year (only for AIOS)l Maximum of Rs. 5,000 will be sanctioned
Eligibilityl DOS Life Members (Delhi Members only)l Accepted paper for presentation / poster / instruc-
tion courseTime since last DOS Fellowship
Preference will be given to member who has not at-tended conference in last three years. However if no ap-plicant is found suitable the fellowship money will bepassed on to next year. Members who has availed DOSfellowship once will not be eligible for next fellowship fora minimum period of three years.Authorship
The fellowship will be given only to presenting au-thor. Presenting author has to obtain certificate from allother co-authors that they are not attending the said con-ference or not applying for grant for the same conference.(Preference will be given to author where other authorsare not attending the same conference). If there is repeat-ability of same author group in that case preference willbe given to new author or new group of authors. Prefer-ence will also be given to presenter who is attending theconference for the first time.Quality of Paper
The applicant has to submit abstract along with fulltext to the DOS Fellowship Committee. The committee willreview the paper for its scientific and academic standard.The paper should be certified by the head of the depart-ment / institution, that the work has been carried out inthe institution. In case of individual practitioner he or sheshould mention the place of study and give undertakingthat work is genuine. The fellowship committee whilescrutinizing the paper may seek further clarification fromthe applicant before satisfying itself about the quality andauthenticity of the paper.Credit to DOS
The presenter will acknowledge DOS partial finan-cial assistance in the abstract book / proceedings.
The author will present his or her paper in the imme-diate next DOS conference and it will be published inDJO.Points awarded1) Age of the Applicant Points
a) < 35 years 10
Delhi Ophthalmological Society Fellowship forPartial Financial Assistance to Attend Conferences
The DOS Travel Fellowship will be calledDOS Fellowship for Partial Financial Assistance to Attend Conferences
b) 36 to 45 years 07c) 45 years plus 05
2) Type of Presentationa) Instructor/ Co-instructor of Course 10b) Free Paper (Oral) 08c) Poster 05
3) Institutional Affiliationa) Academic Institution 15b) Private Practitioner 20
4) DCRS Rating in the immediate previous yeara) 50-100 05b) > 100 10c) < 50 not eligible
Documentsl Proof for age. Date of Birth Certificatel Letter of acceptance of paper for presentation / poster
or instruction coursel Details of announcement of the conferencel Details of conference attendant in previous three
years.l Copy of letter from other national or international
agency / agencies committing to bear partial cost ofconference if any.
l At least one original document should be provided,that is ticket, boarding pass or registration certificatealong with attendance certificate of the conference.
l Fellowship Money will be reimbursed only after sub-mission of all the required documents.Dr. J C Das (President DOS), Dr. Gurbax Singh (Vice
President DOS), Dr. Kamlesh (Editor) Dr. Lalit Verma (Li-brary Officer), Dr. Sudipto Pakrasi (Member) and Dr. JeewanS. Titiyal (Secretary DOS) will be the members of DOS Fel-lowship for Partial Financial Assistance to Attend Con-ferences Committee.
Application should be addressed to President, DOS.Application should reach secretary’s office before 31st Julyand 31st January for international conference and before30th September for national conference. The committeewill meet thrice in a year in the month of August, Octoberand February with in 2 weeks of last date of receipt ofapplications. The committee will reply within four weekof last date of submission in yes/no to the applicant. Nofellowship will be given retrospectively, that means priorsanction of executive will be necessary.Dr. Jeewan S. Titiyal, Secretary DOS,Delhi Ophthalmological Society, R.No. 476, 4th Floor,Dr. R.P. Centre for Ophthalmic Sciences AIIMS, AnsariNagar, New Delhi – 110029
DOS FELLOWSHIP
70August, 2003 DOS Times - Vol.9, No.2
Ever since its introductionby Schepens in 1940s, Bin-ocular Indirect Ophthalmos-copy has been an indispens-able part of ocular examina-tion, especially for patientswith retinal diseases.Though it is relatively moredifficult to learn than directophthalmoscopy, once mas-tered, it is a very convenienttool for rapidly and easilyevaluating a large area ofretina. Indirect Ophthalmos-copy gives the advantage ofbrighter illumination, biggerfield of view, stereoscopicimage, and the ability to scanthe whole retina upto andeven beyond the ora serrata.Before going on to the detailsof performing the procedure,the optical principle behindthis technique (Fig. 1) mustbe understood. The indirectophthalmoscope consists ofa bright light source, whichdirects the defocused lightbeam towards the patient’seye. This light enters thepatient’s eye through the di-lated pupil and gets reflectedfrom the retina or the struc-tures in its path. The emerg-ing reflected beam gets fo-cused by a hand held con-densing lens to form a realand inverted image betweenthe condensing lens and the
Indirect Ophthalmoscopy:Principles, Technique andPractical TipsVinay Garodia MD, DNB, FRCS
Visitech Eye HospitalAdvanced Centre for Vitreo Retinaand Lasers, 55, Mall Road,Delhi - 110009.
observer’s eyepiece (Fig. 1).The image is inverted andreversed right for left. By theuse of prisms, the viewingsystem reduces the effectiveinterpupillary distance (IPD)to fit the patient’s pupil, andthus aids in obtaining a ste-reoscopic view. The ad-vanced indirect ophthalmo-scopes come with the ‘smallpupil option’, wherein themovable prism system can
reduce the effective IPD, forexamining the eyes withsmaller pupil. However,when effective IPD is re-duced, stereopsis is also de-creased. There are also op-tions for incorporating filtersto the light source or to theviewing system. This is use-ful during performing Fluo-rescein angioscopy (blue fil-ter over light source and yel-low filters over the oculars),or the use of red free filters toenhance contrast of vascularstructures.
Indirect Ophthalmoscopyis the easiest and fastestmethod of evaluating thewhole of retina. It has theadvantages of a large field ofview, especially helpful inevaluating larger structureslike retinal detachment ortumour and for providing abird’s eye view to evaluate
the relative position of a pa-thology in relation to theother structures in the retina.With this procedure, espe-cially if employed withscleral depression, one canview upto the extreme pe-riphery of retina and can evenevaluate the pars plana.There is less distortion ofimage of the fundus in reti-nal periphery than in othertechniques. The bright light
source ensures better visual-ization through the hazymedia. The stereoscopic viewadds a third dimension toobservation and is useful inevaluating elevated lesionslike retinal detachment,macular or disc edema, etc.Moreover, it has an advan-tage of being used during reti-nal procedures like cryopexy
and during buckling sur-gery, without compromisingon the sterility of the operat-ing field.
The disadvantages are theneed for dilatation (whichanyway is necessary for anyprocedure that involves athorough evaluation ofretina), the technique is rela-tively more difficult to learnand master, inexperiencedexaminers may find the in-verted and reversed imagedifficult to interpret.
Technique for IndirectOphthalmoscopy
Before performing IndirectOphthalmoscopy, the pupilmust be adequately dilated.The patient must be ex-plained about the procedureand should be brieflywarned about the brightlight that he/she will haveto look into. Before doingscleral depression, the pa-tient must be assured that itis a harmless and painlessprocedure, and is requestedto keep his/her eyes relaxed.For the procedure, an indi-rect ophthalmoscope, a con-densing lens, a scleral de-pressor and a chart to mapthe fundus drawings are re-quired. The condensinglenses are available in differ-
APPLIANCES
Fig. 1: Optical principle of Indirect Ophthalmoscopy. Note therelative positions of Binocular Indirect Ophthalmoscope (BIO),real image (inverted), condensing lens and patient’s pupil.
Indirect Ophthalmoscopy is the easiestand fastest method of evaluating the
whole of retina
71August, 2003 DOS Times - Vol.9, No.2
ent powers (+14, +20 and+28 or +30 Diopters). Thelenses with lesser power (+14D) have a better magnifica-tion (3.5X) but with a smallerfield of view (25o), and re-quire a better pupillary dila-tation. The lenses withhigher power (+28 or +30 D)have a lesser magnification(1.5X) but with a bigger field(55o) and can view the fun-dus through relativelysmaller pupil. An intermedi-ate power lens of + 20 D is agood compromise to obtainan adequate magnification(2.5X) and field (35o), and ismost commonly used.
The patient may be exam-ined in either sitting or su-pine position. The supineposition is easier for the ex-aminer as well as the patient.A motorized chair, whichcan be reclined back com-pletely, is adequate. Theremust be adequate room forthe examiner to move allaround the patient’s head toevaluate different quadrantsof the retina. Before startingthe examination, the exam-iner must be familiar with allthe controls of the instru-ment. Individual machinesdiffer from each other in de-sign, but generally speakingthere are a few features thatare common to most of themachines.
The indirect ophthalmo-scope can either be mountedon a headband or on a spec-tacle. The headband is morecomfortable, especiallywhen used for long duration.There are two bands, a hori-zontal one to tighten aroundthe forehead, and a verticalband to adjust the height andto support the weight of theinstrument. It is essential thatthe vertical band be adjusted
adequately, so that the hori-zontal band need not betightened too much, whichcan otherwise make the pro-cedure very uncomfortableand tiring for the examiner.Once the headband is se-cured, the viewing portion isadjusted for height andshould fall in the line of sightof the examiner. The ocularsare kept as close to theexaminer’s eye or spectaclesas possible. Next the IPD isadjusted so that both the eyesget a symmetrical view of thelight spot falling on the backof the extended hand of theexaminer. The view througheach of the eyes should besimilar in height and lateral
extent. The lighting system isadjusted such that the illu-minated light patch occupiesupper two-thirds of the fieldof vision. The illuminationintensity is controlled by therheostat in the power supply,and should be kept at theminimum necessary for theexamination. In case of un-cooperative patients, it is bet-ter to start with lower level ofillumination and increase itlater once the patient getsaccustomed to the brightlight. It is preferable to startby examining the less sensi-tive peripheral retina firstand the posterior pole last.Even in peripheral retina, itis better to observe superiorretina first, as initially thepatients have a tendency toroll up the eyes in responseto light, which aids in exam-ining the superior retina.
After the indirect ophthal-moscope has been adjustedproperly, the examinationbegins. The examiner standson the opposite side of thedirection to be examined.The condensing lens is heldbetween the thumb and thefirst two fingers. The ringand little fingers are placedon patient’s cheek to stabilisethe hand. It is better to prac-tice using the non-dominanthand to hold the lens, leav-ing the dominant hand freefor holding the active instru-ment like scleral depressor orcryopexy probe. The patientis asked to look in the supe-rior direction and the binocu-lar indirect ophthalmoscope
is directed towards thepatient’s pupil at a distanceof approximately one arm’slength. A reddish orange re-flex is seen. The condensinglens is inserted into the illu-minated path of the ophthal-moscope approximately 1.5inches away from thepatient’s eye. A small imageof the retina appears whenthe lens is centered properly.The lens is then drawnslightly away from the pa-tient to fill it with the imageof the fundus. While per-forming this maneuver,slight lateral and verticaladjustments in lens positionare done to keep the imagecentered. Slight tilting andadjustment of lens is requiredto reduce the annoying re-flection. This step of posi-tioning and adjusting thelens is a bit difficult during
the learning stages, and oneneeds to practice it. The littlefinger resting on the patient’scheek acts as a pivot for move-ments of the lens. It is impor-tant not to get too close to thepatient, as it makes the jobmore difficult. Once a clearview is obtained, the exam-iner swivels about the pointin the patient’s pupil, keep-ing the examiner’s headset,condensing lens, and thepatient’s pupil in an align-ment.
The examiner must con-stantly remember that theimage is inverted and re-versed, so as to maintain thealignment of his/her move-ments. After finishing evalu-ating the superior retina, thepatient is asked to move his/her eyes in the other direc-tions, while the examinerstands in the opposite direc-tion of eye’s position. Thepatient’s face has to bemoved slightly to overcomethe obstacles like nose andforehead of the patient. Toovercome the physical ob-stacle of nose, it is useful toturn the patient’s faceslightly towards the exam-iner (away from the directionof eye movement) whenevaluating the temporalretina. The patient must beconstantly reminded to keepboth the eyes open. The pa-tient may either be instructedto look in the various direc-tions, or else, he/she may beasked to follow the thumb ofhis/her extended hand.
Scleral DepressionThis technique allows the
evaluation of the peripheralmost parts of the retina andpars plana. However, thetechnique of scleral depres-sion can not be applied to the
APPLIANCES
the technique is relatively more difficultto learn and master, inexperienced ex-aminers may find the inverted and re-
versed image difficult to interpret
72August, 2003 DOS Times - Vol.9, No.2
eyes with open globe inju-ries, or recently operated cata-ract surgery. The patient isassured and is asked to re-lax his/her eyes. The scleraldepressor can be introducedover the lids or directly on theconjunctiva, after applyingtopical anesthesia. The ex-aminer stands opposite tothe area of interest. The pa-tient is asked to look towardsthe direction of the examinerand the depressor is placedon the eyelids in the oppo-site direction, in the area ofinterest. Now the patient isasked to gently look awayfrom the examiner, towardsthe direction of the area ofinterest (the direction wherethe depressor has been ap-plied), while the depressoralso gently moves in the di-rection of the movement ofeye. This ensures a gentlepressure on the globe, whichis appreciated by indirectophthalmoscopy. The scleraldepressor can be movedslightly side to side or inantero-posterior directiongently to show the area of
interest. When performedproperly, it is painless pro-cedure and adds a lot of clini-cal information, especiallywhen looking for small reti-nal dialysis or retinal breaksin the periphery.
Interpretation and Mappingof Findings
It takes some time to getused to and make sense of theinverted image in indirectophthalmoscopy. Once theexaminer gains experience,he/she may cognitively cor-rect the image mentally andthen draw it normally. Forthe beginners though, it issimpler to draw the image asit is seen, and then turnaround the paper on whichit is drawn. This automati-cally corrects for the imageinversion. In case of anydoubt, one must not hesitateto go back and recheck thefindings.
It is very useful to note theposition of any pathologywith respect to the normalanatomical landmarks onthe retina (Fig. 2). The vortex
Fig. 2: The normal anatomic structures in the eye can be used asaids to orientation and are useful in mapping the lesions relativeto the position of equator and prominent landmarks.
Fig. 3: A sample fundus diagram, showing the universal colourcoding system for a few common lesions and structures.
veins ampulla are seen alongthe equator. The long ciliaryveins may be seen at 3’Oclock and 9’O clock posi-tions. The pathology mustalso be localized in relationto some branching vessel andmust be faithfully mapped inthe fundus drawing, to facili-tate locating the same later.The fundus drawing is madeon a special Amsler’s chart,which has twelve clockhours marked and has threeconcentric circles made on it.The innermost circle repre-sents to the equator, themiddle circle the ora-seratta,and the outer most circle themid-point of pars plana. Aproper and detailed map-ping of normal and abnormalfindings on this chart is agood practice. There are a fewconventions to fundus chart-ing. Symbols and colour cod-ing are used to represent thevarious findings, a few ofwhich are detailed in Figure3. The advantages of the useof conventions include lessneed to label with words andenhanced communication
with the colleagues. Disk isalways shown with red mar-gin. Arteries are made withred lines, whereas veins aremade of blue lines. Attachedretina is red and detachedretina is coloured blue. A reti-nal hole or tear is shown asred with blue outline. Chor-oidal lesions are depictedbrown; any vitreous opacityis depicted with green.
To conclude, regular useof indirect ophthalmoscopyis the biggest pre-requisite tomaster this extremely usefultechnique. Mastering thistechnique is essential forsomeone who wishes to per-form retinal cryopexy andretinal detachment surgery.While learning this tech-nique, one must be persistentand should not hesitate inconsulting the more experi-enced colleagues, whenevera problem is faced. With regu-lar practice, the steps of thistechnique become a secondnature to the examiner andopens up a new vista for ex-ploring the intricacies anddetails of posterior segment.
APPLIANCESAPPLIANCES
73August, 2003 DOS Times - Vol.9, No.2
Advances in microsurgi-cal techniques and postop-erative care have made it pos-sible to achieve a high rate ofcorneal graft clarity in a num-ber of clinical conditions.Despite all these advances,many corneal surfaces re-main irregular and havehigh degrees of astigmatismfollowing penetratingkeratoplasty (PK). The visualoutcome of a clear cornealgraft (Figure 1) is often com-promised by high degrees ofastigmatism, which may beassociated with largeamounts of myopia, ani-sometropia and less com-monly with hypermetropia.Binder in a series of patientsafter corneal transplantationand cataract extraction re-ported that only 21 of the 43eyes achieved refractive errorwithin 2D of emmetropia. Re-fractive unpredictability af-ter penetrating keratoplasty(PK) is extremely commonwith most studies document-ing a cylinder of 4 to 5Dioptres (D) and significantanisometropia. Refractiveanisometropia and highpostoperative astigmatismcan compromise thepatient’s return to normalbinocular function. Ani-sometropia may also causeheadache, photophobia,tearing, diplopia and blurred
Visual Rehabilitation afterPenetrating KeratoplastyRajesh Sinha MD, Jeewan S Titiyal MD, Namrata Sharma MD,Rasik B Vajpayee MS, FRCS (Ed.)
vision. The ametropia fol-lowing PK is usually relatedto factors like the configura-tion of trephine incisions,donor-recipient graft dispar-ity, irregular and inappropri-ate tightness of sutures, dif-ferences in thickness of do-nor and recipient woundedges creating a step, spe-cific situations like keratoco-nus or difficulty of lenspower calculation in the pa-tient undergoing corneal
triple procedure.Management of Ametropia1. Spectacles2. Contact Lens3. Surgical Correction
a. Selective SutureRemoval
b. Arcuate Keratotomyc. LASIK
In cases of small to mod-erate amounts of ametropiawith less than 3 D of ani-sometropia and or astigma-tism less than 4D, spectaclecorrection is tolerated. Manyof these patients who cannotbe rehabilitated with spec-tacle correction can be aidedby contact lens. Contact lensfitting has been reported tobe successful in as many as80 to 90% of these cases. Softcontact lenses are effective
only for correction of post-keratoplasty refractive errorswith low astigmatism,whereas rigid gas permeablecontact lenses are usuallyrequired when astigmatismof a high degree is present.
The main aims of contactlens fitting after penetrating
Keratoplasty involve correc-tion of residual refractive er-ror, comfort commensuratewith a reasonable wearingtime, and maintenance ofocular health.
Among all contact lenses,the rigid gas permeable(RGP) lenses, owing to theirhigh oxygen transmissibilityand the ability to correct forthe corneal toricity, are anobvious choice to provide vi-sual rehabilitation in an eyewith corneal graft (Figure 2).
In the phakic or aphakicgraft with low toricity, dailywear soft contact lenses canbe used. The use of extendedwear soft contact lenses ismore problematic as moststudies have shown that thecorneal graft tolerates the ex-tended wear contact lenspoorly and that its use insuch patients is associatedwith corneal vascularisation.This increases the risk ofgraft rejection and hencegraft failure.
Although lenses can befitted when sutures are inplace, rigid lenses are usu-ally fitted after suture re-moval, 12 to 18 months post-operatively. Prior to lens fit-ting, K readings and mani-fest refraction should bestable over a period of acouple of months.
Some patients might be
Cornea and Refrective SurgerySerivice, R.P. Centre forOphthalmic Sciences, AIIMS,Ansari Nagar, New Delhi - 29 Figure 2Figure 1
The visual outcome of a clear corneal graft isoften compromised by high degrees of
astigmatism, which may be associated withlarge amounts of myopia, anisometropia and
less commonly with hypermetropia
MANAGEMENT PEARLS
74August, 2003 DOS Times - Vol.9, No.2
having a very high astigma-tism and an irregular cornealsurface. These patients maynot gain a sharp acuity withcontact lens alone. A combi-nation of spectacle correctionover contact lens might helpin these cases.
However, many patients,especially the elderly are un-able to tolerate, handle or
maintain contact lenses.Contact lens intolerance maybe caused by ocular, occupa-tional or systemic factors. Inthese cases, surgical inter-vention may be required toachieve visual rehabilitation.
Apart from the spectaclesand the contact lenses vari-ous maneuvers have beenused to correct post-kerato-plasty anisometropia andhigh degrees of astigmatismwith a variable rate of suc-cess. In pseudophakic eyes,intraocular lens exchangecan decrease anisometropiaand scleral wound manipu-lation may minimize astig-matism. However, this sur-gical intervention maythreaten the graft and mayresult in endothelial decom-pensation, rejection or othercomplications.
Post-keratoplasty astig-matism has been treated bythe various forms ofincisional refractive surgerysuch as relaxing incisions,astigmatic keratotomy andwedge resections. Relaxingincisions at the graft host in-terface are associated withincreased risk of wound de-hiscence, especially wherethe posterior edges of the
wound are poorly apposed.Further, variable healing pe-riod in these cases may pro-duce fluctuations in cornealtopography, refraction andkeratometry. Proceduressuch as radial keratotomyperformed in corneal graftshave shown less predictableresults and a high rate ofcomplications and their use
is presently discouraged.Hexagonal keratotomy tocorrect hypermetropia hasbeen used post keratoplasty,with limited success owingto the high incidence of astig-matism.
Arcuate keratotomy withplacement of incisions justinside the graft-host junctionhas been found to be quiteeffective by many surgeons.However, the effect of theseincisions may not be thesame as in other cases as in acorneal graft, the graft-hostjunction acts as second lim-bus.
The advent of excimer la-ser surgery has opened newperspectives for the treat-ment of post-keratoplasty re-fractive errors. However,photorefractive keratectomy(PRK) is associated with sig-nificant amount of stromalhaze, which is related to themagnitude of the ablations,required for these cases, andis coupled with the regres-sion of the obtained refrac-tive effect. Excimer photo-ab-lation-induced graft rejectionand loss of best spectaclecorrected visual acuity havealso been reported in someof these cases.
More recently, severalstudies have reported the useof laser in situ keratomileusis(LASIK) in eyes that haveundergone corneal grafting.LASIK offers several advan-tages over PRK in the treat-ment of myopia and astigma-tism. These advantages in-clude rapid visual rehabili-tation, decreased stromalscarring, less irregular astig-matism, minimal regressionand the ability to treat greaterrange of refractive disorders.Further, it also preserves theBowman’s membrane (un-like PRK) and the anatomi-cal structure of the corneaand respects the normal cor-neal physiology.
LASIK should be consid-ered as a therapeutic optionin post-PK patients in whomthe conventional opticalmethods have failed. Largerefractive errors, anisometro-pia not successfully cor-rected with spectacles andcases of contact lens intoler-ance should be consideredfor LASIK. LASIK has beenused more commonly to treatmyopia or myopic astigma-tism and less commonly hy-
permetropia or hyperopicastigmatism. The requiredsafety interval between PKand LASIK has not been pre-cisely established. Most ad-vocate a minimal period of 2to 3 years after a successfulpenetrating keratoplasty forperforming LASIK. Most au-thors advocate that sutureremoval in these eyes should
have taken place 3 to 6months prior to the proposedLASIK procedure.
The contraindications ofperforming LASIK after PKfor residual refractive er-rors/ anisometropia includemarked peripheral cornealvascularization, thin hosttissue, wound ectasia, a sig-nificant graft override orwound malapposition andminimum central cornealthickness of less than 500µmand simulated keratometryreadings below 38D orgreater than 55D. If cataractis present, phacoemulsi-fication with an appropriatelens implant may be a bettermethod of addressing ani-sometropia or ametropia.
All patients undergoingLASIK after corneal graftingshould be explained that theprimary goal of LASIK afterPK is resolution of sufficientmyopia and astigmatism toallow spectacle correction ofthe residual refractive error.
Modificationsrecommended in surgicaltechnique of LASIK
The corneal flap diameter
should be more than the di-ameter of the graft, whichusually ranges from 7.5 to8.5mm. It is recommendedthat initiation of the flap edgeexactly at the graft host junc-tion should be avoided sothat the flap drapes thewound and better woundapposition of the flap is cre-ated to the recipient bed. Fur-
Arcuate keratotomy with placement ofincisions just inside the graft-hostjunction has been found to be quite
effective by many surgeons
MANAGEMENT PEARLS
Contact lens fitting has been reported tobe successful in as many as 80 to 90%
of these cases
75August, 2003 DOS Times - Vol.9, No.2
ther, this also possibly en-sures that the contractileforces emanating from thegraft host junction both incentripetal as well as in the
centrifugal directionswould be released.
A 160µmmicrokeratome head shouldbe used in these cases as be-ing in more superficiallamellar plane it fulfils theneed to release the periph-eral traction lines.
Some have recom-mended a prolonged wait-ing period of 5 minutes forbetter adherence of the flapas flap adherence takeslonger in post-keratoplastypatients owing to poorerendothelial function.
Target refraction may beemmetropia or decrease inanisometropia with a goalof complete resolution ofcylinder.
Although graft rejectionafter LASIK has not beenreported unlike PRK, topi-cal steroids should be pre-
scribed for a longer thanusual period after the pro-cedure to minimize the riskof graft rejection.
For cases with more than
6D of astigmatism, one caninitially perform arcuate in-cision to reduce the cylinderand following a period ofstability (3-4 months),LASIK can be performed tocorrect the residual refrac-tive error.
Sequential treatment hasbeen recommended in post-keratoplasty astigmatismrather than the simulta-neous treatment. In thistreatment modality, ahinged lamellar kerato-tomy is performed firstwhich induces a biome-chanical response of thecornea, resulting in sub-stantial change in its shapedue to the previously exist-ing alterations of their natu-ral biomechanical state. Inthis technique, the flap israised as a first stage pro-cedure. A two stage surgery
has been recommended inwhich excimer laser abla-tion is done 3 months laterafter re-lifting the flap. Thelamellar cut performed,leads to release of the con-tractile forces which ema-nate from the graft hostjunction. This is subse-quently followed by the re-alignment of the corneal tis-sue. The main change inastigmatism occurs within1 day after cutting the flap,but further minor progres-sion or regression of the re-fractive effect may be seenupto 3 months postopera-tive day.
Astigmatic correction byaugmentation with arcuateincisions in the corneal stro-mal bed after the laser abla-tion has also been tried. Thearcuate cuts were performedwith a guarded diamondknife set with a micrometerat 350µm. Two arcs of 60° to80° were performed in theaxis of the steep meridian.The decision to perform ar-cuate cuts is based on an as-sessment of the cylindricaltreatment possible with thelaser (maximum of 5D) andconstraints imposed by thepossible induced hyper-metropia and insufficientoptical zone size.
MANAGEMENT PEARLS
LASIK should be considered as atherapeutic option in post-PK patients
in whom the conventional opticalmethods have failed
The risk of damage to thecorneal transplant or thegraft host-wound interfaceor both is the most dreadedcomplication after LASIK.Wound dehiscence after PKis a well-described phenom-enon, which can occur imme-diately, or years after PK. InLASIK, intraocular pressureis elevated to more than 65mmHg and there is a risk ofwound dehiscence with thepossibility of extrusion of theintraocular contents.
To conclude, the appear-ance of a clear corneal graftmay be very satisfying tothe surgeon. However, itmay not be the same withthe patient. At times, itmay be very annoying dueto the amount of ametropiaand resulting anisometro-pia. Many treatment mo-dalities have been de-scribed which includesearly suture adjustment, se-lective suture removal, spec-tacle correction, contact lens,various incisional proce-dures and the modern dayLASIK. In spite of the adventof so many advanced pro-cedures, rigid gas perme-able contact lens, in ouropinion, remains the main-stay of visual rehabilita-tion in such cases.
76August, 2003 DOS Times - Vol.9, No.2
Chemical burns representpotentially blinding ocularinjuries and constitute a trueocular emergency. Recentstudies put the incidence ofocular burns of the eye at7.7% - 18% of all ocular trau-mas. The majority of victimsare young and exposure oc-curs at home, work and in as-sociation with criminal as-saults. Alkali injuries occurmore frequently than acidinjuries. Lime injuries are thecommonest in our setup. In-juries due to sulfuric acidthough less severe are alsobecoming common becauseof battery use in inverters.
Chemical injuries of theeye produce extensive dam-age to the ocular surface epi-thelium, cornea, anterior seg-ment and limbal stem cellsresulting in permanent uni-lateral or bilateral visual im-pairment. Damage to limbalstem cell result in cornealconjunctivalisation, vascu-larization, chronic inflam-mation and recurrent or per-sistent epithelial defects. Se-vere damage to conjunctivalcells causes mucus defi-ciency and persistent sub-conjunctival inflammationresulting in severe dry eyeand fibrosis of subconjuncti-val tissue.
Ballen first suggested aclassification, which wasmodified by Roper-Hall to
Chemical Injuries:Management GuidelinesRitu Arora MD., Vandana Jain MBBS. , D.K.Mehta MS, MNAMS
provide prognostic guide-lines based on the cornealappearance and extent oflimbal ischemia. This classi-fication has become thebenchmark since its intro-duction in 1965.
Roper Hall classificationGrade I: There is no cor-
neal opacity or limbal is-chemia and the prognosis isexcellent.
Grade II: The cornea ishazy with visible iris details,there is ischemia of less than
one-third of the limbus andthe prognosis is good.
Grade III: There is sufficientstromal haze to obscure irisdetails, ischemia of one thirdto one half of the limbus andthe prognosis is guarded.
Grade IV: The cornea isopaque with no view of irisor pupil, there is ischemia ofmore than one-half of limbusand the prognosis is poor.
A new classification hasbeen proposed by Dua et althat take into account the ex-tent of limbal involvement inclock hours and the percent-age of conjunctival involve-ment. Dua et al stressed theinadequacy of the currentlyfollowed RoperHall classifi-cation that is reflected in theinconsistencies of successrates reported in literature.
This is particularly true forgrade IV burns (50-100%limbal ischemia) which areequated with poor prognosis.
Emergency (Immediate)Treatment
Immediate irrigation is ofparamount importance afterthe chemical and thermalburns. In most cases victimsare disabled by severe ble-pharospasm with ensuingdisorientation, which can beovercome by passive open-ing of the lids and intermit-
tent application of topicalanesthetic. All the aspects ofconjunctiva and corneashould be irrigated and thepatient should be asked tolook in all directions. Cottontipped applicator soaked inEDTA 1% can be used to fa-cilitate cleaning of cul-de-sacfrom lime particles.
The effectiveness of rins-ing therapy can be assessedby using universal indicatorpaper to determine the pH ofthe external eye. Irrigationmust be continued as long asthe pH value remains out-side the normal range.
Several methods of facili-tating irrigation have beensuggested, including im-plantation of a T-tube anduse of an irrigating sclerallens. But it is believed that
these irrigating systems mayprovide continuous irriga-tion but they fail to flush theocular surface homoge-neously especially the cul-de-sacs. On one hand it istrue that composition of irri-gating fluid is less importantthan the speed with which itis initiated, on the other handthe argument that still re-mains is the choice of irrigat-ing fluid. Osmolarity of cor-neal stroma is 420 mOsm/L,so if irrigation is done with ahyposomolar fluid such aswater, there is additionaluptake of water into corneaalong with diffusion of thechemical into the deeper lay-ers of the cornea.
So Kuckelkom et al hasrecommended the use of irri-gating fluids with higher os-molarity for initial irrigation.Sterile lactated ringer andbalanced salt solution (BSS)are believed to be more effec-tive than normal saline (NS).A new amphoteric solutiondiphoterine is proposed forinitial irrigation, it bindsboth alkalis and acids. 0.4%diphoterine has a pH of 7.4and an osmolarity of 820mosm/L.
After a thorough irriga-tion, it is important to assessthe degree of burn with re-spect to conjunctival necro-sis, limbal ischemia, cornealdamage, intraocular pres-sure and degree of intraocu-lar penetration.
Medical TreatmentTreatment in acute stage
is aimed at promoting ocu-lar surface epithelialization,augmenting corneal repairand controlling inflamma-tion with the objective of pre-venting scarring sequelaeand severe visual loss. Topi-
Guru Nanak Eye Centre,Maulana Azad Medical College,New Delhi.
MANAGEMENT PEARLS
Alkali injuries occur more frequentlythan acid injuries. Lime injuries are the
commonest
77August, 2003 DOS Times - Vol.9, No.2
cal antibiotics are instilled toprotect the eye from second-ary infection along with my-driatic-cycloplegic agents toprevent the formation of pos-terior synechiae and the de-velopment of ciliary spasmwith its attendant discomfort.
Modalities to promote re-epithelialization beinga. Tear substitutes:
Preservative free tear sub-stitutes can ameliorate per-sistent epitheliopathy, re-duce the risk of recurrent ero-sions and accelerate visualrehabilitation.b. Bandage soft contact lens:
Hydrophilic high oxygenpermeability lenses shouldbe preferredØ Promotes epithelial mi-
grationØ Helps basement mem-
brane regenerationØ Enhances epithelial stro-
mal adhesion protectingocular surface from thewindshield wiper effect oflids.But they may be poorly
tolerated by acutely chemi-cally injured eye.
Various other drugs suchas Fibronectin, Epidermal
growth factor and Retinoicacid are in investigationalstages.
2. Support Repair and Mini-mize Ulcerationa. Ascorbate
Ascorbate is an essentialwater-soluble vitamin that isa cofactor in the rate-limitingstep of collagen formation.Damage to ciliary body epi-
thelium by intraocular injuryresults in decreased secretionof ascorbate and a reductionin its concentration in theanterior chamber, that maylead to impaired collagensynthesis. Oral ascorbate(2g/day) and topical 10%solution formulated in artifi-
cial tears are effective.
b. TetracyclineTetracyclines can protect
the cornea against proteolyticdegradation after moderate tosevere ocular chemical injury.They inhibit matrix metallo-proteinases by mechanismsindependent of their antimi-crobial properties, primarilythrough restriction of the gene
expression of neutrophil col-lagenase and epithelialgelatinase, suppression of a1
antitrypsin degradation, andscavenging of reactive oxygenspecies. Tab doxicycline100mg twice a day can begiven.
c. Collagenase InhibitorsSeveral collagenase in-
hibitors including cysteine,acetylcysteine, sodiumethylenediaminetetraaceticacid (EDTA), calcium ETDA,penicillamine and citratehave been reported to be effi-cacious. However acetyl-cysteine is unstable, has lowpotency and has poor cor-neal penetration. Its effect isrelatively weak compared tocitrate and markedly inferiorto tetracyclines. 10% solu-tions of sodium citrate madeup in artificial tears appliedtopically reduce corneal ul-ceration. Combined treat-ment with ascorbate and cit-rate is superior to treatmentwith either substance alone.
3. Control Inflammationa. Corticosteroids
Corticosteroids reduce in-flammatory cell infiltrationand stabilize neutrophiliccytoplasmic and lysosomalmembranes. Because of un-
Dua’s classification
Grade Prognosis Limbal Conj. AnalogueInvolvement Involvement Scale
I Very good 0 clock hours 0% 0/0%
II Good =3 clock hours = 30% .1-3/1-29.9%
III Good >3-6 clock hours >30-50% 3.1-6/31-50%
IV Good -guarded >6-9 clock hours >50-75% 6.1-9/51-75%
V Guarded-poor >9-<12 clock hours >75-100% 9.1-11.9/75-99.9%VI Very poor Total limbus Total conj.inv. 12/100%
MANAGEMENT PEARLS
Immediate irrigation is of paramountimportance after the chemical and
thermal burns
78August, 2003 DOS Times - Vol.9, No.2
founded fears that they maydelay re-epitheliazation andpotentiates sterile corneal ul-ceration, clinicians are reluc-tant in their use in acute stage.But corticosteroids have noadverse effect on the rate ofepithelial wound healing.The key to successful corti-costeroids use is to maximizethe anti-inflammatory effectduring the window of oppor-tunity in the first 7-10 days,later they can be tapered.
In a study conducted byDavis et al it was suggestedthat a regime of topical ste-roids combined with topicalvitamin C does not causecorneoscleral perforation.But further studies areneeded to validate the riskbenefit ratio of duration ofuse of corticosteroids follow-ing chemical injuries.
b. Progestational SteroidsProgestational steroids
have less anti-inflammatorypotency than do corticoster-oids but they have only aminimal effect on stromal re-pair and collagen synthesis.Medroxy progesterone 1%has been experimentallyshown to inhibit collagenaseand reduce ulceration afterchemical injury, suppresscorneal neovascularisationand minimally suppressstromal wound repair. So af-ter 10-14 days they can besubstituted in place of corti-costeroids. Medroxyproges-terone though not easilyavailable in Indian set up butcan be reconstituted from in-jections.
Scleral lenses and symble-pharon rings prevent appo-sition of tarsal and bulbarconjunctival surfaces that aredenuded of epithelium. Asimpler but still effective
means of decreasing symble-pharon formation is to per-form lysis of conjunctival ad-hesions daily as they form byan ointment coated glass rodor cotton tipped applicator.
Other forms of early treat-ments that have fallen intodisuse include aprotinin,subconjunctival heparin,subconjunctival serum injec-tions, topical vasodilatorsand glued on contact lenses.
Surgical therapyMild to moderate burns
show good response withmedical therapy alone how-ever for severe burns surgi-
cal intervention invariablybecomes necessary. Earlysurgical therapy, if indicatedis directed towards removalof necrotic corneal epithe-lium and conjunctiva, estab-lishment of limbal vascular-ity and re-establishment oflimbal stem cell population.
Amniotic membranetransplantation
Certain properties makeamniotic membrane ideallysuited for use in ocular sur-face reconstruction. It doesnot express HLA-A, B or DRantigens, has antimicrobialproperties, antifibroblastic
activity, cell migration andgrowth promoting activityand anti-inflammatory activ-ity. It acts as a basement mem-brane and facilitates migra-tion of epithelial cells, rein-forces adhesions of basalepithelial cells, promotes epi-thelial differentiation andprevents epithelial apop-tosis. It produces growth fac-tors, inhibits protease activ-ity and acts as a bandagecontact lens. Recently vari-able results regarding the useof amniotic membrane inacute ocular burns have beenreported. Meller et al re-ported that AMT alone wassufficient to restore cornealand conjunctival surface inmild to moderate burns. Insevere burns it restored theconjunctival surface withoutsymblepharon and reducedlimbal stromal inflammationbut did not prevent limbalstem cell deficiency that re-quired further limbal stemcell transplantation. How-ever Dua et al reported fail-ure of AMT to restore ocularsurface or preserve the integ-rity of eye in severe acuteburns. A recent report byKobayashi et al also empha-sized that immediate amni-otic membrane transplanta-tion is useful for mild to mod-erate acute chemical burnsand preserves ocular surfaceintegrity.
Our experience hasshown limited utility of am-niotic membrane transplan-tation for severe chemicalburns with near total limbaland conjunctival ischemia.However for moderate burnsit helped in reducing the de-gree of symblepharon andcreating a smooth base forsecondary intervention at alater date.
MANAGEMENT PEARLS
Chronic burns
Assess- VascularizationConjunctivalisation
SymblepharonCorneal clarity
Clock hours of limbal ischemia
Symblepharon release with AMT with ALTwith or without PK(In 1 or 2 sittings)
Fellow eye normal Fellow eye affected
Limbal auto graft -limbal allograft-Cadaveric limbal allograft-Cultured limbal stem cells
ANG is suited for use in ocular surfacereconstruction. It does not express HLA-A, B or DR antigens, has antimicrobialproperties, antifibroblastic activity, cell
migration and growth promoting &anti-inflammatory activity
79August, 2003 DOS Times - Vol.9, No.2
TenoplastyIn severe injuries the most
immediate concern is the de-velopment of anterior segmentnecrosis due to loss of limbalvascular blood supply. In thissetting prompt reestablish-ment of limbal vascularity mayreduce the subsequent devel-opment of the disastrous con-sequences.
Tenoplasty is based onprinciple of using vital con-nective tissue within the or-bit to re-establish limbal vas-cularity and to facilitate re-epitheliazation. All the ne-crotic conjunctival and epis-cleral tissue is excised fol-lowed by blunt separation oftenon’s tissue from the equa-torial region of the globe andfrom the extraocular muscles.Tenon’s sheet is preparedwith a smooth surface to al-low conjunctival epitheliumto slide on this layer. Thetenon’s flap is then advancedto the limbus and suturedtightly to the sclera. But teno-plasty is less successful ininsuring appropriate andadequate corneal epithelialrecovery.
Limbal stem cell transplan-tation (LSCT)
LSCT restores the normalcorneal epithelial phenotypeafter chemical injury. Success-ful transplantation dependsupon having controlled ocu-lar inflammation with appro-priate medical therapy and in-suring that the graft is prop-erly attached to well vascular-ized conjunctiva. In Grade IVinjuries prior extension of anappropriate vascular supplyto the limbal region by teno-plasty either before or at thesame time as limbal stem celltransplantation is mandatory.While LSCT is extremely use-
ful in the management of uni-lateral chemical injury, it hasnot been extensively appliedto the management of bilat-eral chemical injury. Recentinnovations that can be usedin such cases are limbal al-lograft transplantation or theuse of cultured limbal stemcells.1. Limbal Autograft
In cases of unilateralchemical injuries limbalautografting from the felloweye as an early interventionas early as 3 weeks after in-jury offers the potential of aphenotypically normal ocu-lar surface. This in turn re-duces or prevents conjuncti-valisation of cornea that re-sults in a thickened vascular-
ized, irregular and unstablecornea.2. Living related conjuncti-
val limbal allograftBilateral stem cell loss, as
in cases of bilateral chemicalinjuries, living related al-lograft procedures can bedone. Donor with the bestABO blood and HLA tissuematch is chosen. Surgicalprocedure is similar to con-junctival limbal autografting.But to reduce the risk of rejec-tion systemic immunosup-pression is routinely em-ployed.3. Cadaveric keratolimbal
allograftIf a suitable living donor is
unavailable a cadaveric al-lograft is recommended. Inthis a circular allograft is ob-tained from donor corneal
button that is then sewn intoposition with 10/0 nylonsutures on the corneal sideand 8/0 vicryl sutures on thescleral side. Systemic immu-nosuppression is again em-ployed to prevent allograftrejection. This procedure isadvantageous as it is avail-able to all patients and elimi-nates risk to the donor.4. Cultured limbal stem cells
In 1993 Lindberg et al wereable to propagate ocular epi-thelial cell in vitro. This tis-sue culture work was the ba-sis for recent autologoustransplantation of cultivatedcorneal epithelium. Full thick-ness 1-2mm2 biopsies from thelimbus of healthy eyes weretaken and cultured on acellu-
lar human amniotic mem-brane. These were then autografted onto the fellow af-fected eyes.
So in the future limbalstem cell cultures may be usedas the source for all limbaltransplantation includingautografts and allografts.
However in the acute stageof burns, role of LSCT is notvery well established due tothe associated problems ofinflammation and ischemiathat impair the success ofprocedure.
Conjunctival transplanta-tion
Following an acute chem-ical injury, the role of conjunc-tival transplantation now islargely confined to advance-ment with Tenon’s capsule
to reestablish limbal vascu-larity, in conjunction withlimbal autograft.
Large diameter penetrat-ing keratoplasty, Keratoe-pithelioplasty, Keratopros-thesis and tissue adhesivesmay be used but have failedto produce convincing re-sults.
Advances in ocular sur-face transplantation tech-niques allow late visual re-habilitation of a scarred andvascularised ocular surface.Limbal stem cell transplan-tation for incompletetransdifferentiation and per-sistent corneal epithelial dys-function, and conjunctivaland or mucosal membranetransplantation for ocularsurface mechanical dysfunc-tion produce satisfactory re-sults. Rehabilitation of theocular surface may be fol-lowed if necessary, by stan-dard penetrating kerato-plasty if all aspects of ocularsurface rehabilitation arecomplete or by large diameterpenetrating keratoplasty ifsuccessful limbal stem celltransplantation cannot beachieved but other ocular sur-face rehabilitation is com-plete.
Protocol in acute stage
Ø Immediate irrigation
Ø Assess- limbal and con-junctival ischemia, IOP,corneal clarity and in-traocular penetration
Ø Medical therapy-topicalantibiotics, cycloplegics,tear substitutes, topicalsteroids, ascorbate, citrateand tetracyclines
Ø Surgical therapy-AMT,Tenoplasty, conjunctivaltransplantation and LSCT
MANAGEMENT PEARLS
Chemical injuries of the eye produceextensive damage to the ocular surface
epithelium, cornea, anterior segment andlimbal stem cells resulting in permanentunilateral or bilateral visual impairment
80August, 2003 DOS Times - Vol.9, No.2
Posterior dislocation ofnucleus is a serious compli-cations of phacoemulsi-fication because of morbid-ity to the patient and stressto the surgeon. These re-tained posterior nuclear frag-ments greatly increase therisk of vision threateningcomplications like cornealedema, persistent uveitis,vitritis, refractory glaucoma,cystoid macular edema, vit-reous haemorrhage, retinaltears and retinal detachment.However, post-operativecomplications are relativelylesser and visual recoveryquiet satisfactory after timelyintervention by a vitreo-retinal surgeon.
In this comprehensive ar-ticle, we discuss the pre-op-erative and intra-operativerisk factors for nucleus drop,the early signs of posteriorcapsule rupture (PCR) withnucleus still present in eye,and management of nucleusdrop.
Risk Factors for NucleusDropPre-operativeØ Posterior polar cataractØ Hard cataractØ Total cataractØ Vitrectomised eyeØ Pseudo-exfoliation syn-
drome
Management of DislocatedNuclear Fragment DuringPhacoemulsificationAmit Khosla MD, Jasmita Popli MS
Operative FactorsØ Inexperienced surgeonØ Surgeon over-confidenceØ Topical anaesthesia (in
uncooperative patient)Ø Radial tears in capsu-
lorhexisØ Vigrous hydroprocedures
when AC is full of vis-coelastic
Ø Inability to gauge thedepth during sculpting
Ø Perforating the nuclearplate at 6 O’clock positionduring trenching
Ø Continued aspiration af-
ter fragment removalHigher rates of dropped
nucleus occurred whenphacoemulsification wasstill evolving. Incidence ofposteriorly dislocated lensfragment reported in the lit-erature so far is 0.4% to 4%.With better understanding ofthe procedure and the newerstate of the art phaco ma-chines, the incidence ofnucleus drop is on the de-cline.
Early recognition of PCrupture or zonulodialysis isthe key to avoiding droppednucleus. Any further maneu-ver will increase the likeli-hood of a dropped nucleus.
Therefore, presence of any ofthe warning signs men-tioned below should not beignored.
Signs of Early PosteriorCapsule Rupture/ZonularDehiscenceØ Sudden deepening of the
chamber, with momen-tary expansion of the pu-pil.
Ø Sudden, transitory ap-pearance of clear red re-flex peripherally.
Ø Newly acquired difficultyto rotate a previously mo-
bile nucleus.Ø Excessive lateral mobil-
ity/displacement of thenucleus.
Ø Excessive tipping of onepole of the nucleus.
Ø Partial descent of thenucleus into anterior vit-reous space.
Management of NucleusDrop
As already mentioned,surgical intervention byvitreoretinal surgeon canimprove the visual outcomein a case of dropped nucleusconsiderably. Complica-tions in these cases often re-sult from nucleus retrieval at-
tempts by phaco surgeon.The worst strategy is to try tochase a descending nucleuswith phaco tip. Downwardfluid infusion expands therent and the nucleus ispushed further away. Aspi-rating vitreous places trac-tion on the vitreous basecausing giant retinal tears.The visibility for eventualvitrectomy which has to fol-low is also reduced due tocorneal edema.
Managing DroppingNucleus
A phaco surgeon can at-tempt extraction of a par-tially descended nucleus ifthe conditions are favourablelike a well dilated pupil, apart of nucleus still hookedin the bag and absence of vit-reous prolapse.The surgeonmust stop irrigation andavoid any anterior chamberfluctuations.the possibletechniques include:-Ø Holding the nucleus with
forceps.Ø Viscoexpression by using
a combination of vis-coelastic cannula and in-jected viscoelastic to el-evate the nucleus.
Ø Use of sheet glidesthrough the main woundto stablise the nucleus.
Ø “PAL” technique (poste-rior assisted Levitation)inwhich a cyclodialysisspatula is insertedthrough a pars plana stabincision to support andpush the nucleus into ACfrom below. However,there is risk of iatrogenicvitreous traction andchance of touching theretina with a metalspatula tip.The capsulorhexis must
be broken before nucleus is
Vitreo-Retinal ServicesDepartment of OphthalmologySir Ganga Ram Hospital
MANAGEMENT PEARLS
Early recognition of PC rupture orzonulodialysis is the key to avoiding
dropped nucleus
81August, 2003 DOS Times - Vol.9, No.2
pushed into AC. Enlarge thesection to remove thenucleus. This should be fol-lowed by a thorough anteriorvitrectomy and removal of asmuch of cortex andepinucleus as possible.However, results of this pro-cedure are not as good asthose of PPV.
What an anterior segmentsurgeon can do?
It is essential for the ante-rior segment surgeon to NOTPANIC in the face of such acatastrophic complication.The surgeon must secure thewound. Only dry aspirationshould be attempted. Ante-rior vitrectomy preferably dryvitrectomy under viscoelas-tic should be done with duecare taken to preserve theanterior capsulorhexis andfree the wound of vitreous.Alternative method is to in-troduce vitrectomy cutterfrom the side port and a slowinfusion canula through an-other side port. The fluidshould be directed towardsthe anterior chamber angle.To minimize the traction onretina follow the principleslisted in Table 1.
DO NOT FISH for lensfragments, which are not vis-ible. FINAL VISUAL ACU-
ITY IS DEPENDENT ONTHE EXTENT OF MANIPU-LATIONS DURING INITIALCATARACT EXTRACTION.Though IOL placement canbe done at this stage it re-
duces the surgical optionsavailable to the vitreoretinalsurgeon, as limbal route can-not be used. In additions,bubbles form on the posteriorsurface of IOL during phacofragmentation, reducing thevisibility. At the end of theprocedure, an anterior seg-ment surgeon, if equipped,should perform indirectophthalmoloscopy withscleral depression to localizethe fragments and breaks, ifany, because these will re-quire at least laser or cryoretinopexy.
It is essential for medicole-gal purposes that the cata-ract surgeon FULLY EX-PLAINS TO THE PATIENTwhat has happened, whatcan be done and what is theprognosis.
Though vitrectomy can bedone on the same day as cata-ract surgery, it is reasonablethat the anterior segment sur-
geon observes the patient forsettling down of cornealedema and inflammationand closely follows him upfor emergence of complica-tions listed in Table 2.
Inflammation can be se-vere, to such an extent that asterile endophthalmitis mayresult. Lens debris can forma pseudohypopyon in theanterior segment. The ante-rior segment surgeon shouldput the patient on topicalantiglaucoma medication aswell oral and intravenoushyperosmotic agents.Trabeculectomy in suchcases is not very effective andvitrectomy is the treatment ofchoice.
Managing posteriorlydislocated retinal nucleusfragment
The goal is to remove theremaining nucleus, epinuc-leus and cortex without caus-ing vitreoretinal traction. Forbetter visual outcome a sec-ondary surgical interventionby a vitreoretinal specialistis desirable. Reported meanvisual acuity in nucleus droppatients prior to vitrectomyis 6/60 and post-vitrectomyis 6/9.
ObservationFrequent indefinite fol-
low-up may be sufficient atfollowing instances whenassociated with minimal in-flammation.
(a) Small cortical matter(b) Small epinuclear plate(c) Small nuclear frag-
ment (<25% of lens material)However, even small frag-
ments may be associatedwith severe complications.CME persistent uveitis, glau-coma and drop in visual acu-ity are an indication for sur-gery in such cases.
Timing of SurgeryDropped nucleus is not an
emergency. However, thebest timing of vitrectomy con-tinues to be debated. Somestudies have shown that bet-ter results are obtained whenvitrectomy is delayed to al-low medical treatment of in-flammation, IOP and cornealedema while others report nodifference in visual recoverybetween early and delayedvitrectomy. Advocates ofearly vitrectomy argue thatthe incidence of cornealedema, chronic glaucomaand intraocular inflamma-tion are reduced. Technicallydelayed vitrectomy is easieras posterior vitreous detach-ment (PVD) is created andnucleus becomes softer. We
MANAGEMENT PEARLS
Table 2: Complications associated with nucleus drop alongwith their average reported incidence
Complication Incidence
l Intraocular inflammation 70%
l Secondary glaucoma 50%
l Corneal edema 50%
l Retinal detachment 1.5%
l Choroidal effusions 4.5%
l CME 3.0%
Table 1: Principles to minimize traction:
Ø Avoid aspirating (without cutting) any presenting gel.Ø Attempts to retrieve any lens fragments that started to dis-
locate posteriorly should be made only with vitrectomyhandpiece.
Ø Avoid the use of lens loop, forceps, and other instrumentsthat have the potential to engage and pull on vitreous gel.
Ø Perform a complete limbal vitrectomy before any lensplacement.
Ø Confirm the absence of vitreous to the wound or otheranterior structures at the time of wound closure.
Ø Perform indirect ophthalmoscopy with slceral depressionat the end of the procedure to identify any retinal tears.
The worst strategy is to try to chase adescending nucleus with phaco tip
82August, 2003 DOS Times - Vol.9, No.2
believe that the surgeryshould be performed within2 weeks to expedite visual re-habilitation.
Indications for Surgery1. Eyes with very small re-
tained nuclear fragmentsand epinuclear fragmentswhere inflammation hasnot subsided by 1 to 2weeks.
2. Nucleus fragments largerthan 3mm size or morethan 25% of lens matter.
3. Significant intraocular in-flammation.
4. Poorly controlled second-ary glaucoma
5. Retinal detachment.6. Cystoid macular edema.
Surgical TechniquesThe surgical procedure of
choice is three port parsplana vitrectomy.At manynational conferences ante-rior approach has beendiscussed,but there are noarticles on this approach inliterature or standard textbooks.
Problems of nucleusremoval through anterior/limbal approach withvitrectomyØ Incomplete vitrectomyØ Vitreous tractionØ PVD cannot be generated
Ø Increased incidence of RDThe possible techniques
are1. Soft nucleus
– only vitreous cutter2. Moderate to hard nucleus
– Bimanual crush tech-nique with lighted pick, pipeand vitreous cutter
– Ultrasonic fragmenta-tion3. Extremely hard nucleus
– Limbal extraction withuse of PFCL
– Phacofragmentation– Bimanual crush tech-
nique
PhacofragmentationAn adequate initial three
port vitrectomy completelyreleasing the fragment is es-sential to avoid inadvertentvitreous traction.Phacofragmentation usesphacofrag needle which islonger and narrower thanphaco tip and does not re-quire a sleeve. Endoillumi-nator is used to stabilize andfeed the nuclear fragment. Aseparate infusion portshould be used to maintainglobe anatomy. 5% to 20% ul-trasonic power in pulsemode with moderate suctionrate of !00 to150mmof Hg issufficient for efficient nucleusextraction. Venturi pump isbetter than peristaltic pump
for phacofragmentation.Continuous vacuum reducesthe chances of fragmentsdropping onto retina. Frag-ments on retinal surfaceshould be carefully aspi-rated and moved to the midvitreous cavity (at least 5 to 6mm from retina) to avoid ul-trasonic damage to retina.
Use of PFCLPFCL are clear fluids with
high specific gravity (1.76 to2.03) and low viscosity.Their short-term exposurecauses minimal toxic effect toretina. Removal with PFCLis not so easy and is used lessfrequently now. It can be usedin very hard cataract. A thor-ough three port pars planavitrectomy (PPV) with re-moval of vitreous aroundnucleus is essential beforeinstilling PFCL as an unre-lieved vitreous traction maycause peripheral retinalbreak giving PFCL access tosubretinal space. PFCL is in-jected below the nucleus toelevate it on the liquid sur-face to mid vitreous cavitywhere both manipulationand fragmentation are safer.One must fill PFCL only upto equator. Not only doesthis provide a reasonableworking space, but also pre-vents trapping of lens par-
ticle at the vitreous base.Thus, PFCL acts as a cush-ion, which prevents retinaltrauma, especially to maculaduring fragment removal byraising it away from retinalsurface. It is especially help-ful in associated R.D. as itserves to reattach the retina.Indirect ophthalmoscopywith scleral depression is amust at the end of the proce-dure, wherein one must scru-tinize periphery for retainedfragments and retinalbreaks. Studies report thatPFCL does not alter visualprognosis, however, a selec-tion bias is likely as PFCL isused in more complicatedcases.One common compli-cation is that PFCL is re-tained in the eye.
Results– 60% cases have visual
acuity of 6/12 or better.– Results are better in cases
with least manipulationsby phaco surgeon
SummaryØ Explain to the patient.Ø Secure wound/no vitre-
ous.Ø Refer to VR surgeon
within two weeks.Ø Control inflammation,
glaucoma.Ø Good results with mini-
mal fishing.
MANAGEMENT PEARLS
DOS Credit Rating System Report CardDCRS July 2003 � Army Hospital (R&R)
Total No. of Delegates ....................................................................................................................................................................... 121
Delegates from Out side (N) .............................................................................................................................................................. 114
Delegates from Army Hospital (n) ........................................................................................................................................................ 7
Overall assessment by outside delegates (M) ............................................................................................................................ 888.5
Assessment of case presentation-I (Dr. Lt. Col.A. Banarji) by outside delegates ...................................................................... 803.5
Assessment of case presentation-II (Dr. Lt. Col. (Mrs.) Madhu Bhaduria) by outside delegates ............................................. 814.5
Assessment of clinical talk (Dr. D.P. Vats) by outside delegates ................................................................................................. 862.5
83August, 2003 DOS Times - Vol.9, No.2
Careful planning of thesurgical approaches to or-bital lesions is very impor-tant to achieve the best re-sults. Based on the findingsof the axial and coronal CTsand MRI along with ultra-sonography the most preciseapproach can be determinedto either biopsy, debulk or re-move a tumor.
Before embarking on Or-bital Surgery a thoroughknowledge of surgicalanatomy of the orbit is nec-essary. Orbital surgeryshould be learnt in astepwise manner under theguidance of a senior surgeonotherwise the rate of compli-cations is likely to be morewith sometimes-disastrousresults.
Important points in the sur-gical anatomy: The orbit con-sists of seven bones namelyfrontal, sphenoid, zygomatic,palatine, maxillary, ethmoidand lacrimal. The roof iscomprised of frontal boneand lesser wing of the sphe-noid. Fossa for the lacrimalgland and trochlear fossa arelocated there. The suture linebetween the frontal bone andthe ethmoid, lacrimal, max-illary and nasal bones marksthe level of cribriform plateand is also the location of theforamina for the anterior andposterior ethmoidal arteries.The distance between theanterior lacrimal crest to theoptic foramen is 45 to 50 mm.
Surgical Approach for OrbitotomyS.M. Betharia, MD
Dr. R.P. Centre for OphthalmicSciences, AIIMS, Ansari Nagar,New Delhi - 110029
To avoid damage to opticnerve, posterior dissectionshould not extend beyondposterior ethmoidal artery at35 mm. from the rim. The lat-eral wall can be resected 20to 25 mm posteriorly at thelevel of the zygomatic sphe-noid suture line before themiddle cranial fossa is en-tered or the inferior orbitalfissure is interfered with. Theanterior third of the greaterwing of sphenoid and thezygoma form not only the lat-eral wall of the orbit but alsothe medial wall of the tem-
poral fossa. Posteriorly, theposterior third of the greaterwing of sphenoid forms boththe lateral orbital wall andthe anterior boundary of themiddle cranial fossa. Thezygomatic temporal sutureline is at the same posteriorlevel as the zygomatic sphe-noid suture and thus marksthe posterior limit of lateralorbitotomy (20 mm). The su-perior incision is made at thelevel of zygomatic frontalsuture. If made higher itwould risk entering the an-terior cranial fossa. The infe-rior bone incision is made atthe same level as the supe-rior limit of the zygomaticarch.
Surgical approachesThe orbit can be ap-
proached from superior, me-
dial, lateral and inferior ap-proaches. ENT surgeon willapproach the orbit from me-dial or inferior side whereasthe neurosurgeon will ap-proach it from superior side.I shall deal with the surgicalapproaches by the oph-thalmic surgeon, which willinclude anterior and lateralorbitotomy.
Anterior orbitotomyThis can be by transcon-
junctival and transcutane-ous route.
Transconjunctival approachIt allows access to lesions
anterior to equator of theglobe and the anteriorintraconal space. This can becombined with lateralorbitotomy as well. After do-ing 180° conjunctival peri-tomy medial rectus is iso-lated with a muscle hook. 6-0 vicryl suture is passed justbehind insertion. The sutureis tied and double locked.The muscle is thendisinserted from the globe.The globe is retracted later-ally. A soft malleable retrac-tor is placed over the medialrectus to have adequate ex-posure. The mass is excisedin to or biopsy is done. Themuscle is reinserted and con-junctiva is reapproximated.The common lesion removedis usually haemangioma. De-
compression of optic nerve isalso possible by this ap-proach.
Transcutaneous ap-proaches
This can be transeptal orsubperiosteal. The variousincisions named includeBenedict incision, which is asuperior sub-brow incision,Lynch incision on the medialside (anterior ethmoidectomyincision) & vertical lidspilliting incision of ByronSmith. Incision can be placedin the skin crease or inferiorsubcilliary region to hide thescar. Care should be taken toavoid injury to levator whengoing by trans-septal andsub periosteal approaches.The complications of ante-rior orbitotomy include dam-age to levator causing ptosisand damage to variousmuscles causing muscle im-balance and diplopia. Dis-section in the proper tissueplanes, using blunt dissec-tors and judicious use of thecryoprobe go a long way inremoval of encapsulated le-sions like neurilemomma,haemangioma, dermoid cystetc.
Lateral orbitotomyThe incision which is
now a days used is Stallard– Wright incision whichgives better exposure andmore versatility. It is a lazyS-shaped incision startinglateral to the supraorbitalnotch just beneath the lateralhalf of the brow and extendsinfero laterally along the or-bital rim, past the lateral can-thal angle and ending overthe zygomatic arch medial tothe hairline. Sharp dissec-tion is carried through or-bicularis muscle to the peri-
REVIEW
Before embarking on Orbital Surgery athorough knowledge of surgical
anatomy of the orbit is necessary
84August, 2003 DOS Times - Vol.9, No.2
osteum. The bleeding fromorbicularis is controlled withcautery.
The periosteum is incisedwith a scalpal blade about 2mm lateral to orbital rim anddissected from underlyingbone with a Freer elevator.Periosteum should be keptintact for later closure. Oncethe dissection is carried intotemporalis fossa, periosteumand muscle will be firmly ad-herent to bone. Separation isfacililated by introducing agauge sponge into sub peri-osteal dissection plane witha periosteum elevator push-ing it to just behind thesphenozygomatic suture.This results in a clear bonysurface. Bleeding at this pointfrom disruption ofzygomatico temporal arterypassing through lateral or-bital wall is controlled bypressure. The periosteum isfirmly attached at the orbitalrim and is gradually andslowly dissected. Oncewithin the orbital space theperiorbita is easily separatedfrom bone. The dissection ofthe periorbita should not becarried too far posteriorly. Asmall recurrent branch ofmiddle meningeal arterymay be severed at the level ofsphenofrontal suture caus-ing bleeding. Exposure is im-proved by passing four 6.0silk traction sutures aroundthe wound and clamped tosterile drapes. Visualizationis improved by using operat-ing loupes and a fiberopticcoaxial headlamp or an op-erating microscope.
Two cuts are made in thelateral wall by Stryker saw.Exact placement of cuts de-pends upon the size and po-sition of the anticipated le-sion and the exposure re-
quired. The inferior cut ismade at the level of the up-per border of zygomatic arch.A higher incision reducesexposure and lower incisionmakes removal of wall moredifficult and risks fracturinginto inferior orbital fissure.The superior cut should beat or not more than 5 mmabove the frontozygomaticsuture line to prevent en-trance into anterior cranialfossa. The cut should beangled inferiorly about 45degrees to provide stabiliza-tion upon replacement. Theorbital contents and temp-oralis muscle must be pro-tected with malleable retrac-tors during bone cutting. Thebony rim may be fixed byapproximating periosteumonly but greater stability isachieved by suture fixationwith 3-0 nylon passedthrough holes predrilled inthe rim on either side ofplanned cut. The metallicwire should not be used ifpostoperative MRI is antici-pated.
After making bone inci-sions the lateral wall is frac-tured outward using arongeur. The bone fragmentis removed completely and isstored in a saline moistenedsponge till it is replaced.Thinner portion of thegreater wing of sphenoid canbe removed by bone ronguer.Adequate haemostasis mustbe ensured at this point be-fore opening periorbita. Theperipheral and intraconalspace is accessed by openingperiorbita by giving one an-terior-posterior cut above orbelow the lateral rectus andthe cut is extended by per-pendicular incision anteri-orly to form a T shaped open-ing. Injury to lacrimal gland
should be avoided. Tractionon the lateral rectus shouldbe avoided. The muscle andorbital fat should be retractedby malleable retractors toprovide good exposure. Or-bital exploration is best ac-complished with blunt fingerdissection, or by using smallretractors or Freer elevator.Slow oozing from orbit iscontrolled by gentle pressurepacks. Gentle suction canalso be used. Wet field bipo-lar cautery is preferable us-ing long blunt tipped for-ceps.
If the lesion is well de-fined and well encapsulatedcomplete removal can be at-tempted by use of cryoprobe.More infiltrative lesions aremore difficult to remove with-out damage to orbital con-tents. During manipulationof globe or optic nerve fre-quent observation of pupil isessential. It is wise to leavesome lesion behind ratherthan sacrifice ocular functionby over aggressive extirpa-tion. When lesions are bettertreated by means other thansurgery are encountered, abiopsy should be performedand sent for frozen section.After confirming the lesionthe orbitotomy should be clo-sed without further disrup-tion of orbital contents. At thecompletion of surgeryhaemostasis is achieved. Adrain might be requiredrarely and should be placedin the dependent regionthrough a separate stabwound. Periosteral suturingshould not be tight. The or-bital rim is replaced. The pe-riosteum is closed over thebony rim to provide nourish-ment and to reposition thelateral canthal tendon.Muscle and skin layers are
closed separately. Post op-eratively light pressuredressing is applied for 24hrs. Drain is pulled on 1st
postoperative day and su-tures are removed after 5 to 7days. Systemic corticoster-oids should be given intraoperatively and continuedpostoperatively. Systemicantibiotics and anti-inflam-matory drugs and vitaminsupplements are given.
SummaryOrbital surgery needs a
careful planning and goodevaluation along with orbitalCT and ultrasonography. Ifthe lesion is anterior to equa-tor or anterior conal then an-terior orbitotomy can be used.All deep seated lesions pos-terior to equator and in thecentral space need lateralapproach. Well encapsu-lated lesions can be excisedin toto whereas in infiltrativelesions or suspectedmalingnant lesions a biopsycan be planned. StallardWright incision is excellentfor lateral approach. Carefulorbital dissection in propertissue planes, proper expo-sure and use of cryoprobe goa long way in removal of thetumor. Examination of thesize of pupil and fundus ex-amination during and aftersurgery is important. Lightpressure dressing for one dayand systemic steroidsshould be given in all cases.Complications such as pto-sis, diplopia, diminution ofvision or rarely loss of visionmust be explained to patientbefore surgery and properconsent should be obtained.Similarly pre and post opera-tive photographs of the pa-tient and documentation ofC.T. and ultrasonography are
REVIEW
85August, 2003 DOS Times - Vol.9, No.2
essential.
Carry Home MessageØ Orbital surgery can give
very satisfactory results iflearnt properly.
Ø The C.T. is a better inves-tigation than MRI for mostof the cases and should bedone in all cases.
Ø Ultrasonography shouldbe done in all cases.
Ø Approach will be anterioror lateral depending upon
the location of the masslesion.
Ø A thorough knowledge ofsurgical anatomy is amust for orbital surgeon.
Ø A special informed con-sent should be obtainedbefore surgery.
Ø Documentation should becomplete.
Ø It is a very specialized sur-gery and needs propertraining to obtain satisfac-tory results.
REVIEW
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86August, 2003 DOS Times - Vol.9, No.2
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88August, 2003 DOS Times - Vol.9, No.2
“An eye for an eye willmake the whole world goblind” – said MahatmaGandhi, in those troubleddays of our independencestruggle. In the present day’scontext this expression of“an eye for an eye” couldperhaps revolutionize thefield of Eye banking.
Though the first eye bankin India was started as earlyas 1949 at Chennai, till the90’s, our country had to de-pend on Sri Lanka for donoreyes. Concerted efforts fromall quarters during the laterhalf’s of 80’s and 90’s havebrought in drastic changes.Though we cannot claimthat we have reached a stateof self sufficiency in terms ofthe need for the cornea, thereis definite change as far asthe public awareness in con-cerned.
According to IndianCouncil of Medical Research(ICMR) study on blindness,about 25% of the total blindin India are blind due to cor-neal blindness. Out of these2.5 million blind people,even if or so 1 million areblind by a curable cornealdisease, we require really alarge number of people todonate their eyes if we wantto effectively take care of thesepatients
Of all the organ trans-plants, corneal transplanta-tion is unique since: It is easyto harvest from the donor, itcan be done anywhere anddoes not require specializedfacilities such as a sterile the-atre, the equipment neededis minimal and an MBBS doc-
Eye Banking – The PresentScenario in Our CountryR.V. Ramani
tor can be trained to harvestthe donor material in a sci-entific way.
With the availability of ad-vanced storage media, it ispossible to store the cornea.Thus transplantation neednot be done any more as anemergency procedure butcan be elective.
Advances in modernmedicine, such as improvedsurgical techniques, operat-ing with microscopes, im-proved sutures and ad-vances in eye banking havesparked a turn around in thesuccess rate of corneal trans-plants making it among themost successful organ trans-plants.
Eye Banking system has athree tier approach. The dif-ferent constituents are eyedonation centres, eye banksand eye banking trainingcentres. All of them have tobe integrated. They will notbe effective alone.
Eye donation centresshould provide public andprofessional awareness ofeye donation, coordinatewith hospitals and donorfamilies to motivate eye do-
nation, take efforts to harvestcorneal tissue and collect theblood for serology and to en-sure safe transportation ofthe tissues to the parent eyebank.Eye banks should provide around the clock public re-sponse system over the tele-phone and conduct publicawareness programme oneye donation, coordinatewith donor families and hos-pital to motivate eye dona-tion, harvest corneal tissue,process and evaluate col-lected tissue, distribute tissuein an equitable manner, en-sure safe transportation oftissue and carry out regularcorneal transplantation.
Eye Bank training centresshould have eye bank mis-sions along with training forall levels of personnel for eyebanking and research.
Hospital cornea retrievalprogrammes, of late, haveyielded very good results.Under this programme, theeye bank has to select hospi-tals with ICU/ICCUs, solicittheir involvement, give themorientation and motivatetheir key staff, and grief
councilors.Eye bank association of
India has clearly laid downthe code of ethics for eyebanks and the medical stan-dards have been prescribedby the Government of India.Eye banks are expected tomaintain stringent condi-tions needed for processingthe collected tissue. Theseguidelines have broughtabout uniformity in the ap-proach to eye banking.
No religious teaching orleader forbids donation. Thelargest fraction of eye dona-tions in India (approx onethird) has been coming infrom Gujarati speaking Jains.Jain religious leaders con-sider eye donation as a sub-lime form of charity andstress a powerful link be-tween ‘daan’ (charity) and‘moksha’ (salvation).
Islamic nations like Syria,Jordan, Saudi Arabia, Egypt,and Malaysia have acceptedeye donation and allow li-censed eye banks to func-
REVIEW
Dr. R.V. Ramani,Managing TrusteeSri Kanchi Kamakoti Medical Trust,Sankara Eye Centre, Coimbatore
Though the firsteye bank in India
was started asearly as 1949 atChennai, till the90’s, our countryhad to depend on
Sri Lanka fordonor eyes.
Sharing the grief, few words ofconsolation, putting forth the
gratitude of the community towardsthe donor family, regular remembranceof the act of eye donation, all of them
go a long way
89August, 2003 DOS Times - Vol.9, No.2
tion. Prominent leaders haveissued statements towardseye donation.
Most of the eye donationsin the State of Kerala is of-fered by the Christian com-munity through activeChurch-affiliated socialworkers with support fromclergy that preaches eye do-nation.
Hindu mythology isstrewn with episodes on eyedonation. The story of thelegendary Kannapan whooffered his eyes to LordShiva, has more than in-spired many to pledge theireyes.
Under the Transplanta-tion of Human Organs Act,1994 (THOA),the qualifica-tion of doctors permitted toperform enucleation (surgi-cal eye removal) has been re-duced from MS (Ophth.) toMBBS. Eye donation in Indiais always decided by thedonor’s surviving relativesand not by the actual donor,and that enucleating doctorsalways have to legally obtaina written consent from therelatives of the deceased be-fore they actually remove theeyes.
The THOA ’94 Act whileit defines punishment and
strictures for persons/insti-tutions contravening condi-tions laid down therein, itsadly does not contain anysuggestions to improve eyebanking.
Eye Banking has to be ap-proached with sustainedcommitment. It has to be de-veloped as a “movement”.The role of constant cam-paigns to create awarenessamong the general publicand the youth can never beover emphasized. Publicitymaterials, audio visual pre-sentations and the mediaplay vital role. The myths andmisconceptions about eyedonation is not only preva-lent among the villagers, eventhe urbanites and the edu-cated lack clear knowledgeand perception of eye dona-tion. Once their misconcep-tions on eye donation, theprocess of enucleation, theoutcome and the follow upare made clear to the generalpublic, nothing preventsthem from coming forward totake up this most humanitar-ian act.
The entire process shouldhave a humanitarian touch.It should never assume a rou-tine mechanical approach.Sharing the grief, few wordsof consolation, putting forththe gratitude of the commu-nity towards the donor fam-ily, regular remembrance ofthe act of eye donation, all ofthem go a long way. Promptand immediate response toan eye call, a clean processof harvesting, organisedevaluation and utilization,
REVIEW
Monthly Meetings CalendarFor The Year 2003-2004
27th July, 2003 (Sunday)Army Hospital
30th August, 2003 (Saturday)Sir Ganga Ram Hospital
27th September, 2003 (Saturday)New Institute/Hospital
19 October, 2003 (Sunday)DOS Midterm Conference
2nd November, 2003 (Saturday)R.P. Centre for Ophthalmic Sciences
29th November, 2003 (Saturday)Dr. Shroff’s Charity Eye Hospital
27th December, 2003 (Saturday)New Institute/Hospital
31st January, 2004 (Saturday)Safdarjung Hospital
28th February, 2004 (Saturday)M.A.M.C. (GNEC)
28th March, 2004 (Saturday)Mohan Eye Institute
3-4th April, 2004 (Saturday & Sunday)Annual DOS Conference
follow up and feedback tothe donor family, few wordsof appreciation and remem-brance, all of them have to beincorporated in the manage-ment of modern eye banking.
Science and modern tech-nology have made visionrestoration after cornealtransplantation an absolutereality. Our eye surgeonsand technicians are fast ac-quiring the skills. If this tech-nological advancement is
According to Indian Council of MedicalResearch (ICMR) 25% of the total blind
in India are blind due to cornealblindness
ably supported by committedcampaigners in differentparts of the country, eyebanking would soon becomea success story in every stateof our country.
Soon there will be a day,when the common man says,
“Do not bury;Do not burn;
Donate Eyes”– Those immortal
eyes.
90August, 2003 DOS Times - Vol.9, No.2
—————————————————————————————————————————————————————Event Conference Date Venue Contact Person and Address——————————————————————————————————————————————————————
Advanced Programme on 23rd- 24th Dr. R.P. Centre Contact : Mr. Sujay Debnath,Soft Contact Lenses Fitting Aug. 2003 for Ophthalmic M/s Bausch & Lomb Eye Care India Pvt. Ltd.& Management Sciences, AIIMS, Ph : 011-26601160, 26601161, Mobile : 9810752026
New Delhi Email : [email protected]
National Workshop on 17th-18th Dr. R.P. Centre Contact : Prof. R.B. Vajpayee, Dr. Jeewan S. TitiyalPhacoemulsification Sept. 2003 for Ophthalmic 492, 4th Dr. R.P. Centre for Ophthalmic Sciences,
Sciences, AIIMS, AIIMS, New Delhi - 110029, IndiaNew Delhi Ph : 26593192, 26588852-65, Ext. 3192, 3146
Fax : 011-26588919 Email : [email protected]
8th Dr. R.K. Seth Memorial 2nd Park Royal International Contact: Dr. Sunita Lulla C/o. CME Dept. VenuSymposium on Low Vision Oct. 2003 Nehru Place, Eye Institute & Research Centre, 1/31, Sheikh"An Overview" New Delhi Sarai-II, New Delhi-17, Ph.: 91-11-29251155,
29251156, 29251951, 29252417, Fax: 91-11-29252370,E-mail: [email protected]
Ophthacon 2003 10th-11th LLRM Medical College, Contact Person : Dr. Sandeep Mithal,(38th U.P.State Ophthalmology Oct. 2003 Meerut, (U.P.) Upgraded Department of Ophthalmology,Conference) LLRM Medical College, Meerut, (U.P.)
Email : [email protected] : 91 - 121 - 2763133
Eye Topia 2003 19th India Habitate Centre Contact Person: Dr. Jeewan S. Titiyal,Mid Term DOS Oct. 2003 Lodhi Road, New Delhi Secretart (DOS) R.No. 476, 4th Floor,
Dr. R.P. Centre for Opthalmic Sciences,New Delhi - 110 029Ph.: 26589549, Fax : 26588919,E-mail: [email protected]: dosonlin.org
Annual DOS Conference 3rd-4th India Habitate Centre Contact Person: Dr. Jeewan S. Titiyal,April 2004 Lodhi Road, New Delhi Secretart (DOS) R.No. 476, 4th Floor,
Dr. R.P. Centre for Opthalmic Sciences,New Delhi - 110 029 Ph.: 26589549,Fax : 26588919, E-mail: [email protected]: dosonlin.org
Forthcoming Events – NATIONAL
Event Conference Date Venue Contact Person and Address———————————————————————————————————————————————————
XXI Congress of thre ESCRS 6-10 Sept. MUNICH, Contact: ESCRS Temple House, Temple Road2003 GERMANY Blackrock, Co. Dublin, Ireland
Tel: + 353 1 209 1100, Fax: + 353 1 209 1112e-mail: [email protected]
Joint Meeting of the European 13-16 Sept. LISZT, Contact: Ferenc KuhnVitreoretinal Society & 2003 HUNGARY Web: www.evrs.org/meetingsInternational Society ofOcular Trauma
United Kingdom and Ireland 18-19 Sept. CHESTER, Tel: +44 164 2854 054, Fax: +44 164 2231 154Society of Cataract and 2003 UK Email: [email protected] Surgeons Web: www.euroasiancongress.com
Joint European Research 8-11 Oct. ALICANTE, SPAIN Contact: EVER, Fax +32 16336785Meeting in Ophthalmology 2003 Web: www.ever.be, Email: [email protected]
INTERNATIONAL
EVENTS
91August, 2003 DOS Times - Vol.9, No.2
Proliferative vitreore-tinopathy (PVR) is charac-terised by migration, meta-plasia and proliferation ofretinal pigment epithelialcells, glial cells and mac-rophages leading to forma-tion of fibrocellular mem-branes on both surfaces ofthe detached retina which oncontraction causes distortionand elevation of the retinathat induces a secondary trac-tional retinal detachment1.
PVR is seen in 5 – 10 % ofrhegmatogenous retinal de-tachments and is the mostcommon etiology of failure ofscleral buckling surgery.PVR is also a common com-plication of perforating inju-ries to the posterior segment.
Classification of PVRIn 1983, the Retina Soci-
ety proposed a classificationsystem for PVR2. This classi-fication consists of fourgrades:
A – Minimal – Vitreoushaze and pigment clumps
B – Moderate – Wrinklingof inner retinal surface,rolled edges of break, vascu-lar tortuosity
C – Marked – Full thick-ness, fixed retinalfolds
C1 – One quadrantC2 – Two quadrantsC3 – Three quadrantsD – Extensive – Fixed
retinal folds in fourquadrants
D1 – Wide funnelD2 – Narrow funnelD3 – closed funnelThis classification system
has following disadvan-tages:
Proliferative VitreoretinopathyNeena Kumar MD, Rajvardhan Azad MD, FRCS (Ed), Yog Raj Sharma MS,Atul Kumar MD, Rajpal MD
Ø There was no clinical cor-relation between the mostsevere form (grade D) andvisual prognosis.
Ø There was limited quanti-fication of extent of dis-ease.
Ø This system did not in-clude PVR anterior to theequator.In 1991, an updated clas-
sification system was pro-posed that included addi-tional factors such as ante-rior tractional and prolifera-tive components, more de-tailed descriptions of poste-rior contraction types and the
presence of subretinal mem-branes3
The new classificationsystem consists of the follow-ing modified PVR grades:
A – Pigment clumps in thevitreous cavity, vitreous haze
B – Retinal wrinklingbreaks with rolled edges, reti-nal rigidity, vasculartortuousity, and decreasedvitreous mobility
C – Full thickness fixedfolds (subdivided into ante-rior and posterior forms)
Extent of involvement ex-pressed in clock hours (sub-divided into contractiontypes):1. Focal posterior – single or
multiple isolated folds
posterior to vitreous base.2. Diffuse posterior –
confluence of focal epicen-ters posterior to vitreousbase.
3. Subretinal proliferations –bands of moth eatensheets; extent quantified ifretina is elevated.
4. Circumferential tractionalong the posterior edge ofvitreous base with centraldisplacement of retinaand radial folds posteri-orly.
5. Anterior traction – vitre-ous base displaced to parsplicata, iris or pupillary
margin.Shortcomings of these
classifications are that theydo not take into account im-portant features that influ-ence the prognosis.1. Number, location and
size of retinal breaks2. Number and type of pre-
vious operation3. Time course and biologi-
cal activity of the prolif-erative process.
Pathophysiology of PVRStages of development ofPVR1. Cellular activation
Exposure of large area ofthe pigment epithelium tothe vitreous cavity4 and
breakdown of blood ocularbarrier5 are the stimuli for thecellular activation and mi-gration. The pigment epithe-lial cells, glial cells andprimitive fibroblastic ele-ments move both in responseto vitreous convection cur-rents and to physical- me-chanical forces such as ther-mal shock induced bycryopexy and in response tochemotactic stimuli to siteswhere they exert traction orbegin to proliferate.6
1. ProliferationRetinal pigment epithelial
(RPE) cells and intraretinalglial cells are in the restingphase and do not activelyproliferate under normal cir-cumstances. However, in re-sponse to ischemic, thermalor mechanical injury, thesecells as well as fibroblasticelements from the choroids,sclera and other unknownsources begin to proliferate.RPE cells and glial cells un-dergo metaplastic changeand get transformed intomyofibroblast. These cellsalong with fibroblasts formopaque, contractile mem-branes.5,6,7,8
2. Extracellular matrixelaboration and remodeling
Membranes in PVR con-tain extracellular matrixcomposed primarily of col-lagen and various gly-cosaminoglycans, in addi-tion to cellular elements (RPEcells, glial cells, fibroblastsand macrophages).9 collagenis secreted by fibroblasts,
Dr. R.P. Centre for OphthalmicSciences, AIIMS, Ansari Nagar,New Delhi - 110029
REVIEW
PVR is seen in 5 – 10 % ofrhegmatogenous retinal detachments and
is the most common etiology of failureof scleral buckling surgery
92August, 2003 DOS Times - Vol.9, No.2
RPE cells and glial cells asprocollagen which later onundergoes posttranslationalmodification leading to col-lagen fiber formation.
3. ContractionThe membranes recov-
ered from the eyes with PVRcontain abundant cells andextracellular components.Their morphology suggeststhat these cellular mem-branes are capable of exert-ing traction on the retina andvitreous in a manner similarto the contraction exerted bysyncytial smooth muscle el-ements.9,10 Another mecha-nism for contraction of col-lagen is also suggestedwhich is called hypocellulargel contraction. Cells pro-duce contraction of collagenlattices and by analogy vit-reous collagen in the absence
of frank membrane by pull-ing individual collagen fi-bers toward themselves us-ing alternating extensionand retraction of their lame-llipodia and subsequentlypiling up collagen in smallbundles adjacent to them-selves.11,12
Factors which initiate andhasten the process of PVR
1. RPE dispersion intothe vitreous cavity and ontothe inner retinal surface thatoccurs at the time of retinaltear formation
2. Cryotherapy which re-leases viable RPE cells intothe vitreous cavity
3. Specific serum compo-nents (i.e. fibronectin andplatelet derived growth fac-tors) stimulate cellular migra-tion and proliferation. Theseserum components may gain
access to the vitreous cavityat the time of the retinal tearif vitreous hemorrhage oc-curs or after the breakdownof the blood ocular barriercaused by cryotherapy, di-athermy and laser treatment.
4. RPE cells release TGF-b, a potent stimulator of fibro-genesis
Prognostic featuresI. Number, size and loca-
tion of retinal breaksThe size and number of
retinal breaks potentially in-fluence the amount ofretinopexy applied andthereby influence the degreeof breakdown of the blood-ocular barrier and in the caseof cryotherapy, the numberof RPE cells dispersed intothe vitreous cavity. The loca-tion of retinal breaks, mostimportantly their location
with respect to periretinalmembranes, determines theease with which they can beclosed at the time of surgery.
II. Anteroposterior locationof the transvitreal sheetThe anteroposterior loca-
tion of the transvitreal sheetdetermines the ante-roposterior location of thecircumferential buckle incases where vitrectomy is un-necessary. In addition, the lo-cation of the transvitrealsheet is often an indicationof how far anteriorly the pre-retinal membranes can bedissected from the retina. Theentire undissectable regionmust be supported with a cir-cumferential buckle.
III.Severity of contractionwithin the vitreous baseCell mediated contraction
of the vitreous base is a uni-versal feature of PVR. Sever-ity of vitreous base contrac-tion as well as extent of adja-cent undissectable preretinalmembranes reflect a poorprognosis for retinal reat-tachment. It needs a high cir-cumferential buckle andretinectomy in severe cases.
IV.Severity of poste-quatorial preretinalmembrane formationThe most important prog-
REVIEW
Fig. 3: PVR Grade C [Fixed retinal fold intwo quadrouts (arrow)]
Fig. 4: PVR Grade D1 Fig. 5: PVR Grade D2
Fig. 1: PVR Grade A
Fig. 2: PVR Grade B [Inferior giant tear withrolled edges (arrow)]
93August, 2003 DOS Times - Vol.9, No.2
nostic feature regarding thesemembranes is the degree towhich they can be removedat the time of vitreous sur-gery.V. Number of previous op-
erationsThe greater the number of
previous operations per-formed on an eye, the worsethe prognosis. This may re-sult from an increase in in-flammation and breakdownof blood-ocular barrier.VI.Severity and location of
subretinal membranesDense subretinal mem-
branes adjacent to optic nerveand macula holding theretina in napkin ring con-figuration require more ex-tensive dissection with largeretinotomies to allow accessto the subretinal space to ad-equately relieve traction.
Principles of treatment ofPVRü Close all retinal breaksü Counteract retinal tractionü Minimize recurrence of
tractionü Choose optimal timing of
intervention
Surgical management ofPVR
The surgical managementof PVR is complex and in-volves numerous decisionsand manipulations oftenbased on subjective assess-ment because no two eyes areexactly same. Some of thesecontroversies are one stage ortwo stage surgery, removingor retaining of crystallinelens, early or delayed sur-gery, silicone oil or long act-ing gases as tamponade, re-moval or retention of siliconeoil and use of PVR suppress-ing agents.
Role of scleral bucklingprocedure/ two stagesurgery for PVR:
The concept of scleralbuckling alone or two stagesurgery for PVR was pro-posed by R.G. Michel(1984,1990),13 M. Glaser(1990),14 Stephen Ryan(1985).15 They observed thatclosing retinal breaks even inwhat seems to be advancedcases of PVR eliminated theneed of vitreoretinal surgeryin many cases. In casevitreoretinal surgery was re-quired it allowed time formaturation of membranes,which takes 6-8 weeks. After6-8 weeks membranes can beremoved as single sheet. Earlymembranes are fragile anddifficult to dissect. This prob-
ably also limits recurrencerate. Thus there is a rationalefor those few cases in whichit is possible to identify andclose the breaks and therebyreattach the retina and post-pone vitreous surgery. 1
Grizzard and Hilton (1982)reported 23.4% success withscleral buckling in stage C3
and D1 and 0% in D2 (34.7%in all stages).15 Yoshida et alreported 47% reattachmentin cases of severe PVR.16
Vitreoretinal surgery forPVR
A 3600 broad and highbuckle with or withoutencirclage is used to relieveanterior vitreous traction thatis often not completely dis-sected. Three scleral ports aremade for infusion,endoillumination and in-
traocular instruments. Crys-talline lens even if clear isremoved by phaco-fragmentor in patients morethan 30 years of age and vit-rectomy probe in less than 30years of age. This assists inbetter dissection of mem-branes especially in anteriorPVR. Membrane dissection isdone using vitreoretinal pick,intraocular forceps and scis-sors. All traction should berelieved before fluid-air ex-change is done otherwiseexisting tears will enlargeand air will spreadsubretinally. Transvitrealdrainage of subretinal fluidis done through preexistingbreaks or a posteriorretinotomy. After fluid-airexchange retinal breaks are
treated with photocoagula-tion.
Other modalities in useare long acting tamponadeslike inert gases (C3 F8, C2F6)and silicone oil. Perfluo-rocarbon liquids help inmembrane dissection. Reti-nectomy and retinal tacks arerequired in cases ofunrelievable traction.
Pharmacologic agents forprevention of PVR1. Anti-inflammatory
agents:Corticosteroids reduce in-
flammatory response in theeye thereby moderating thebreakdown of blood ocularbarrier.
2. Drugs that inhibitcellular proliferationsa. 5-FU
b. Daunorubicinc. Retinoidsd. Immunotoxine. Taxolf. Colchicine
3. Drugs that interfere withthe synthesis, secretionand posttranslationalmodification of collagena. Antimetabolitesb. Cis-Hydroxyprolinec. Penicillamine
4. Drugs that affect bindingof cells to components ofthe extracellular matrixand collagena. RGDSb. Heparinc. Low molecular weight
HeparinThe efficacy of these phar-
macological agents howeverhas not been clearly estab-lished. None of the drugstested to date is fully satis-factory either because the ef-fect on membrane formationis only transient or becauseof toxicity.
References
1. Ryan SJ. The pathophysi-ology of proliferativevitreoretinopathy and itsmanagement. Am. J.Ophthalmol. 1985; 100:188-193.
2. Hilton G, The Retina Soci-ety Terminology Commit-tee. The classification ofretinal detachment withprolifrative vitreoretino-pathy. Ophthalmology1983; 90: 121-125.
3. Machemer R. AabergT.M., Freeman H.M. et al.An updated classificationof retinal detachment withproliferative vitreoretino-pathy. Am. J. Ophthalmol.1991; 112: 159-165.
4. Vidaurri – Leal J. andGlaser B. Effect of fibrin on
REVIEW
PVR is also a common complication ofperforating injuries to the posterior seg-
ment.
94August, 2003 DOS Times - Vol.9, No.2
morphologic characteris-tics of retinal pigment epi-thelial cells. Arch.Ophthalmol. 1984; 102:1376-1379.
5. Campochiaro P.A., BryanJ.A. III, Cpnway B.P. andJaccoma E.H.: Intravitrealchemotactic and mitoge-nic activity implicationsof blood retinal barrierbreakdown. Arch.Ophthalmol 1986; 104:1685-1687.
6. Campochiaro P.A., GlaserB.M. Mechanism in-volved in retinal pigmentepithelial cell chemotaxis.Arch. Ophthalmol 1986;104; 277-280.
REVIEW7. Glaser B.M., Cardin A.
and Biscoe B. Proliferativevitreoretinopathy: themechanism of develop-ment of vitreoretinal trac-tion. Ophthalmology 1987;94: 327-332.
8. Miller B., Miller H,Patterson R. and Ryan S.J.Retinal wound healing,cellular activity at thevitreoretinal interface.Arch. Ophthalmol. 1986;104: 281-285.
9. Machemer R. Massiveperiretinal proliferation, alogical approach totherapy. Trans AmOphthalmol. Soc.1977; 75:556-586.
10. Kirmani M., Ryan S.J. Invitro measurement of con-tractile force of trans-vitreal membranes formedafter penetrating ocularinjury. Arch. Ophthalmol1985; 103: 107-110.
11. Blumenkranz M.S.,Hartzer M. Contractilemechanism in prolifera-tive vitreoretinopathy(PVR). Invest. OphthalmolVis. Sci. 1986; 27 (suppl.)188.
12. Michels R.G. Treatment ofcomplicated retinal de-tachment. In retinal de-tachment. 2nd edition.1990.
13. Glaser B.M. Surgery forproliferative vitreoretino-pathy. Retina. Vol. III, Sec-ond edition: 2265, 1990.
14. Grizzard W.S. and HiltonG.F. Scleral buckling forretinal detachment com-plicated by periretinalproliferation. Arch.Ophthalmol 1982; 100: 419-422.
15. Yoshida A., Ho, P.C.,Schepens C.L., MacMeelJ.W. and Duncon J.E. Se-vere proliferative vitreo-retinopathy and retinaldetachment:II. Surgicalresults with scleral buck-ling. Ophthalmology 1984;91: 1538-1543.
95August, 2003 DOS Times - Vol.9, No.2
DOS QUIZ
Rules:l Among the above intermingled alphabets, ophthalmic terms are hidden.
l No abbreviations are used. Let us see who can find the most number of words. Good luck.
l Please send your entries to the DOS office latest by 25th August, 2003.
l Prize Rs.500/- Courtesy: Syntho Pharmaceuticals
l Quiz Trophy will be given to the member who answers maximum number of quizes in a yearduring the Annual GBM of DOS.
Jugglery
1. U S O I T E R V ___ ___ ___ ___ ___ ___ ___ ___
2. C E L U I F R N O S ___ ___ ___ ___ ___ ___ ___ ___ ___ ___
3. O N U T N E S B ___ ___ ___ ___ ___ ___ ___ ___
4. T R E Y I T C V O M ___ ___ ___ ___ ___ ___ ___ ___ ___ ___
5. L C T A E T I ___ ___ ___ ___ ___ ___ ___
6. S L A M R E ___ ___ ___ ___ ___ ___
7. U T I C L I S V A S ___ ___ ___ ___ ___ ___ ___ ___ ___ ___
8. R T E I O T N H Y P A ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___
9. E S A L E ___ ___ ___ ___ ___
10. O L S C I N I ___ ___ ___ ___ ___ ___
DOS QUIZ NO. 21. Epithelial lining of canaliculus is by…………………............................................………………………...
2. Under Vision 2020 program target for cataract surgical rate for India is…………..................................
3. Most common ocular feature of sarcoidosis is …………………………………….....................................
4. Intravitreal dose of Gancyclovir is ………………………………………….……........................................
5. Most common organism causing bleb related endophthalmitis is………………….................................
6. Posterior lenticonus is seen in…………………………………………...………….......................................
7. Most common presenting feature of Stargadt’s disease is…………………………...................................
8. Which extra ocular muscle has nerve supply from orbital surface………………….................................
9. Oral dose of Vitamin A in 9 month old child is…………………………………........................................
10. Conc. of Amphotericin B in fungal corneal ulcer is……………………………….....................................
96August, 2003 DOS Times - Vol.9, No.2
Juxtafoveal CNVTwenty two eyes of twenty
two patients were includedin the study with fluoresceinangiographic evidence of
Juxtafoveal CNV and BCVAbetween 20/200 & 20/50. 14eyes with juxtafoveal CNVwere secondary to AMD witha mean follow up of 24.57
weeks (range 12 - 64 weeks)and 8 eyes with idiopathicjuxtafoveal CNV with amean follow up of 32.57weeks (range 12-64 weeks).
In a mean follow up of24.6 weeks in the juxtafovealAMD group, the Visual Acu-
Stabilization in AMD IdiopathicVisual Acuity ( n = 7 ) ( n = 7 )
No Change 42.85 % 71.4 %
= 5 letters 71.4 % 100 %
> 5 letters, = 10 letters 100 % 100%
Fig. 6. Fundus photographs and FFA showing a patient of laseredextrafoveal idiopathic CNV with juxtafoveal recurrence subjected toTTT, note the stabilization of the letter visual acuity and partial resolu-tion of the membrane.
Fig 5. Colored fundus photographs and FFA of a patient with smallidiopathic JF CNV treated with TTT, decrease in intensity and size ofhyperfluorescence
Fig. 7. A patient of idiopathic CNV treated with TTT shown in theabove colored fundus photographs and FFA, note the complete resolu-tion of the membrane.
Fig. 8. Colored fundus photographs and FFA of a patient of JuxtafovealCNV secondary to AMD treated with TTT, note stabilization of lettervisual acuity and partial resolution of the membrane.
ity improved or stabilized in78.57% eyes (n = 14) at 3months, 57.24% eyes (n = 7)at 6 months, 50% eyes (n = 4)at 9 months and 50% eyes (n= 2) at 1 year follow up.
Stabilization of the visualacuity was defined as either
CURRENT PRACTICE
In TTT heat is delivered to the choroidand retinal pigment epithelium using a
diode laser at 810nm
Transpupillary Thermo Therapy Continued from page 61
97August, 2003 DOS Times - Vol.9, No.2
before TTT, 51.29 ± 22.05 sec.,52.71 ± 25.37 sec.& 60 ± 59.4sec. at three, six and twelvemonths respectively. Hence,there was no significant in-crease in the mean readingdifficulty of the patients(Graphs 3and 4).
In a mean follow up of32.5 weeks in Idiopathicgroup, Visual acuity im-proved or stabilized in87.5% (n =8) eyes at 3 months,71.42% (n =7) eyes followedat 6 months and none of eyesfollowed at 9 months and 1year. Contrast threshold sta-bilized or improved in all theeyes during the course of fol-low up. All the eyes that hadscotoma (n = 3) and metamor-phopsia (n = 3) on theAmsler's grid showed stabi-lized or improved the sc-otoma scores during thewhole follow up period. Themean reading speed was 68.5± 36.66 sec. before TTT, 62.25± 38.79 sec, 71.57 ± 52.62 &41.5 ± 2.12 at three, six and
This figure compares the results of TTT in subfoveal CNV in ourstudy to those subjected to PDT and placebo group in the TAPstudy.
Distribution of patients with Subfoveal CNV who lost < 15letters from baseline at 12 months
CURRENT PRACTICE
improvement or mainte-nance of visual acuity simi-lar to the pre TTT level or fallof up to 5 letters of the ETDRScharts (i.e. ± 1 line). Contrastthreshold stabilized or im-proved in 71.42% of the eyes(n = 14) at 3 months, 71.4%(n = 7) eyes at 6 months fol-low up, 50% (n = 4) eyes at 9
months and 50% (n =2) eyesat 1 year. All the eyes that hadscotoma (n = 2) and metamor-phopsia (n = 4) on theAmsler's grid showed stabi-lized or improved scotomascores during the whole fol-low up period. The meanreading speed was 54.07 ±32.09 seconds for 81 words
twelve months respectively(Graphs 3 and 4).
Advantages of Transpu-pillary Thermo Therapy1. Inexpensive modality of
treatment.2. Proven to be effective3. Well tolerated by the pa-
tients4. Free of systemic side effects5. No need for restrictions
after the treatment6. Results are reproducible7. Less collateral damage to
adjacent retina
ConclusionThe efficacy and safety
has already been vouched bylot of retinologists, howeverexact role of TTT vis a vis PDTand other treatment modali-ties in the management ofsubfoveal and juxtafovealCNV all over the globe needsto be testified by the TTT vsCNV trial underway.
Congratulations!Ø Prof. H.K. Tewari, Chief, Dr. R.P. Centre for Ophthalmic Sciences on being
appointed Dean All India Institute of Medical Sciences (AIIMS), New Delhi.
Ø Prof. Rasik B. Vajpayee, Head of Cornea & Refractive Surgery Service at Dr.R.P. Centre for Ophthalmic Sciences has been awarded Fellowship qua Surgeon(FRCS without examination) by the Royal College of Surgeons of Edinburgh.
Ø Dr. Ashok Garg, Medical Director of Garg Eye Institute & Research Centre,Hisar, has received prestigious “Dr. Jawaharlal Nehru Award of Excellence”and “International Gold Star Millennium Award”.
Ø Dr. Pankaj Varshney for becoming the editor of IMA-DN2 bulletin.
Ø Dr. Prashant Bhartiya for joining as a consultant in Department ofOphthalmology, Bombay Hospital, Indore (M.P.)
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