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OPTICS / REFRACTION/ CONTACT LENSES SESSION369OPTICS/ REFRACTION/ CONTACT LENSES SESSIONChairman: Dr. Prema R., Co-Chairman: Dr. Yasmin Rusi BhagatConvenor: Dr. Rajendra Khanna, Moderator: Dr. Hari Kishan G.AUTHORS’S PROFILE:DR. SUPRIYO GHOSE: MD (‘75), Recipient of Hanumantha Reddy Award, AIOC; S.K. BiswasMemorial Oration. Presently Professor and Chief, R.P. Centre for Oph. Sciences, AIIMS, NewDelhi.Contact: (011)26588957; E-mail: pschiefrpc@yahoo.comA Simple Modification of The Farnsworth Munsell (FM) 100 HueTest for Much Faster Assessment of Colour VisionDr. Supriyo Ghose, Dr. Dinesh Shrey, Dr. Jai Pal Singh, Dr. Pradeep Venkatesh,Dr. Tanuj Dada, Dr. Alok Kumar Ravi, Dr. Twinkle Parmar(Presenting Author: Dr. Supriyo Ghose)The Farnsworth-Munsell 100 hue test is apsycho-technical test designed to test huediscrimination among people with normal colourvision and to measure the areas of colourconfusion in colour-defective observers.Clinically, the test has been used in conjunctionwith the Nagel anomaloscope to classify colourvision abnormalities. 1 This test can be applied topatients suffering from drug toxicities as due tohydroxychloroquine, digoxin, ethambutol, etc. 2The FM-100 hue test has also been noted to beabnormal in optic neuritis and in cases ofglaucoma. Since the introduction of the test,substantial data have accumulated documentingthe effects of age, monocular vs. binocularviewing, and the type of congenital visiondefects.The FM 100 hue test was initiated andpopularised by Farnsworth 3 in the early 1940s –since then, various tests have been developed 4-6such as :- Farnsworth-Munsell Dichotomous D-15 orPanel D-15 test- Lanthony Desaturated D-15- Adams Desaturated D-15Administration: The test consists of 85 movablecolour samples arranged in four boxes of 22colours in the first box and 21 colours in each ofthe remaining 3 [no. 85-21, 22-42, 43-63, and 64-84]. The hue samples were designed to representperceptually equal steps of hue and to form anatural hue circle. The colours are set in plasticcaps and subtend 1.50 at 50 cm. They arenumbered on the back according to the correctcolour order of the hue instruction manual andscoring sheets are provided. One box is presentedat a time. The examiner prearranges the caps inrandom order on the upper lid of the box. Theobserver is instructed to “arrange the caps inorder according to colour” in the lower tray [witha see-through bottom] where the two fixed capsappear. The box is presented for each eye at acomfortable distance under illuminate Cproviding at least 270 lux of natural light. Thegenerally recommended time for arranging eachpanel is 2 minutes. For each panel, the time spenton it is recorded, and whether it was on the firstpanel, second panel, etc.Scoring: Errors are made whenever caps aremisplaced from the correct order. Error scores arecalculated according to the distance between anytwo caps. Score of a cap is the sum of thedifferences between the number of that cap andthe numbers of the caps adjacent to it on eitherside, e.g., if cap number 50 is wrongly positionedsay between 55 and 56, then the score of this capis 55-50 + 56-50 = 5 + 6 = 11. The score of each capis plotted on a circular graph provided. The errorscore is the score with 2 subtracted – i.e., 11-2 = 9.[If this cap no. 50 had been correctly positioned,then the score of that cap would have been 50-49

370 AIOC 2009 PROCEEDINGS+ 51-50 = 2: and with 2 subtracted, its error scorewould have been zero]. Sum of the error scoresof the entire set of caps goes to make the totalerror score (TES). By plotting the scoresgraphically, characteristic patterns are obtainedin specific defects.Manual scoring of error scores and plottinggraphs are of course extremely time consumingand very tedious. To overcome this, variouscomputer-based [but expensive] methods havebeen developed. Our attempt was to saveneedless time-wastage during precious hospitalworking hours, and maximally increase thepatient turn over in the limited time available tothe professional specialist.Materials and MethodsThe original FM 100 hue carrier box consists of awooden cover with 4 elongated boxes inside it.This is an opaque outer cover, so there is obviousdifficulty in photo-documentation. One had tomanually record the scores of caps on sheets, thathugely prolonged the time spent per patient.We modified the FM 100 hue procedure byconverting the outer opaque box into aFig-1: The original FM 100 hue elongated boxes withan opaque wooden cover.Fig-2: Our modified transparent carrier box for the FM100 hue testFig-3: The caps arranged by a reportedly normal subject,according to hue perceived [photographed throughthe transparent plastic top cover] – the arrangement isalmost normal but slightly defective.Fig-4: Showing arranged numbers imaged from the bottomthrough the transparent plastic [along with thePatient ID] – note the slight defects. These numbers arenormally not visible because of the original opaquecover – patient should not flip over the box [to maybepeep at the numbers], though he usually cannot do sowithout upsetting all the caps – anyway, the investigatoris standing by.transparent clear plastic carrier container thatallowed a ready photo-documentation of the‘arranged’ open trays from the top and bottomwithout even opening the box or inverting thecaps. (The inner trays already have a flip-topopaque cover, but a see-through bottom.) Wescreened 200 reportedly normal and 50 knowncolour defectives using this simply modified FM100 hue test, first OD then OS. After digitallycapturing images from both the bottom and topof the ‘arranged’ FM 100 hue box with patient ID,the [used] box was promptly handed over to thenext subject for rearrangement. Scores wereanalyzed at leisure outside hospital time. Timetaken by patient for each eye per test was noted.ResultsThe test running time for each subject wasreduced from 60-75 min to ~15 min with nowaste of invaluable lab hours. Turn over time

OPTICS / REFRACTION/ CONTACT LENSES SESSION371was limited to only capturing two photographs(~60 secs.). The box is relatively cheap and easyto maintain, and also replaced wheneverrequired.DiscussionNowadays, the Farnsworth Munsell 100 HueTest often includes Windows based scoringsoftware, which calculates a numerical score andprovides a graphic display and print-out of the1. Ghose S, Shrey D, Singh J P, Venkatesh P, Dada T,Ravi A K, Bageshwar LMS. Comparative evaluationof Colour Vision (CVn) tests and Colour Perception(CP) in actual work conditions among normals andknown Colour Deficients (CDf). Presented at the65th AIOS Conference, Hyderabad, 02 Feb 2007.2. Cooper H, Bener A. Application of a laserjet printerto plot the Farnsworth-Munsell 100-Hue color test.Optom Vision Sc 1990;67:372-6.3. Farnsworth D. The Farnsworth-Munsell 100 hueand Dichotomous tests for colour vision. J Opt SocReferencessubject's score and status. 2-6 Our simplemodification and adjustment of only the originalbox of the FM 100 hue test proved not only verycost-effective but also permitted rapidassessment of colour vision and quick patientturnover with easy data storage, without theneed of any expensive scoring software but onlya routine camera, preferably digital, for easyretrieval.Am 1943;33:568-78.4. Donaldson GB. Instrumentation for the Farnsworth-Munsell 100-Hue test. J Opt Soc Am 1977;67:248-9.5. Birch J. A method of qualitative scoring of theFarnsworth D-15 panel. Acta Ophthalmol 1982;60:907-16.6. Good GW, Schepler A, Nichols JJ. The reliability ofthe Lanthony Desaturated D-15 test. Optom Vis Sci.2005;82:1054-9.7. Dain SJ. Clinical colour vision tests. Clin Exp Optom2004;87:276-93.AUTHORS’S PROFILE:DR. KAROBI LAHIRIM COUTINHO: M.B.B.S. (’83); D.O.M.S. (’85); M.S. (’86) from GrantMedical College, Bombay, Maharashtra. D.N.B. (’87), Delhi. Fellowship (1989), SankaraNethralaya, Chennai. Recipient of following awards: Best Fellow (’89), Sankara Nethrayala,Chennai; Surgical Excellence (’90), SEMDC, Mumbai and Helpful Citizen (’92), Rotary Club,Mumbai.E-mail: karobi@vsnl.netEvaluation and Comparison of Refractive Errors in Type 1 /Type 2Retinopathy of Prematurity (ROP )Dr. Karobi Lahirim Coutinho(Presenting Author: Dr. Karobi Lahirim Coutinho)The prevalence of higher refractive errorespecially myopic astigmatism was seen in91.66% type 2 treated eyes as compared to 68.18%in type 1. The results of non treated eyes in type1 ranged from myopic to hyperopic astigmatismas compared to 22.22% high hyperopicastigmatism.Materials and Methods90 eyes of 45 patients were selected for this studyfrom Bombay Hospital Institute of MedicalSciences. Examination of Neonates was donefrom 30 days upto 3 months for development ofchanges of ROP and laser treatment atPrethreshold for APROP (Type 2) and atTHRESHOLD for Type 1 was carried out as perthe need. The other neonates were screenedregularly and findings noted on follow ups.Refractive correction was done under cycloplegiaat the 6th month. The children were mummified,held firmly and retinoscopy was done and afternecessary deletions glasses were prescribed ifneeded.Exclusion Criteria(i) Newborns who did not develop any stage ofROP were excluded. (ii) Newborns with birth wtabove 1500 gm. (iii) Newborn above 34 weeksgestation were not selected. (iv) neonates requiringsurgery were excluded from the study.

372 AIOC 2009 PROCEEDINGSTable-1: Refractive errors with Gestational AgeGestational Hyperopic Astigmatism Myopic Astigmatism Mixed Compound EmmetropiaAge (Eyes) (Eyes) Astigmatism (Eyes)Low High Low High Low High26–28 weeks 4 (4.44%) 8 (8.88%) 14 (15.55%) 3(3.33%) 2 (2.22%)28– 30 weeks 9(10%) 5 (5.55%) 18 (20%)30– 32 weeks 6 (6.66%) 17 (18.88%)32– 34 weeks 2 (2.22%) 2 (2.22%)Total 9 (10%) 17 (18.88%) 45 (50%) 14(15.55%) 3(3.33%) 2 (2.22%)Table-2: Refractive errors correlation with Birth Weight.Birth Weight Hyperopic Astigmatism Myopic Astigmatism Mixed Compound Emmetropia(gms) (Eyes) (Eyes) Astigmatism (Eyes)800-1000 6 (6.66%) 20 (22.22%) 4 (4.44%) 2 (2.22%)1000-1500 14 (15.55%) 25 (27.77%) 1 (1.11%)1500-2000 8 (8.88%) 10 (11.11%) 0 (%)Total 28 (31.11%) 55 (61.11%) 5 (5.55%) 2 (2.22%)Table-3: Non Treated EyesHyperopic Astigmatism Myopic Astigmatism Mixed Compound Emmetropia(Eyes) (Eyes) Astigmatism (Eyes)Low High Low High Low High9 (25%) 8(22.22%) 18 (50%) 0 1 (2.77 %) 0 0Table-4: Type I 33 patients – 66 EyesGestation Hyperopic Astigmatism Myopic Astigmatism Mixed Compound EmmetropiaAge (Eyes) (Eyes) Astigmatism (Eyes)Low High Low High Low High26-28 weeks 2 8 0 228-30 weeks 6 5 18 230-32 weeks 4 1732-34 weeks 2 2Total 6+11 = 7 25.75% 45+ 0 = 45 68.18% 0 2+0 = 2 3.03%Table-5: Type II 12 patients – 24 Eyes = 26.66%Gestation Age Hyperopic Astigmatism Myopic Astigmatism Mixed Compound AstigmatismLow High Low High Low High26–27 weeks 2 Eyes (8.33%) 2 Eyes (8.33%) 14 Eyes (58.33%) 3 Eyes (12.5%)27–28 weeks 3 Eyes (12.5%)28– 30 weeksTable-6: Laser treated EyesType I: 15 patients – 28 Eyes; Type II: 12 patients - 24 Eyes; Total: 27 patients – 52 EyesType IType IILow High % Low High %Myopic Astigmatism 18 64.28% 5 14 79.16%Hyperopic Astigmatism 9 32.14% 2 8.33%Mixed Compound Astigmatism 1 3.57% 3 12.5%Total 28 53.84% 24 46.15%

OPTICS / REFRACTION/ CONTACT LENSES SESSION373Table-7: Comparison between Type I and Type IIType IMyopic Astigmatism Hyperopic Astigmatism Mixed Compound AstigmatismLow High Low High Low High26-28 weeks 6 (21.40%) 2 (7.14%)28-30 weeks 12 (42.85%) 2 (7.14%) 5(17.85%) 1 (3.57%)30-32 weeks32-34 weeksTotal 18 (64.28%) 9(32.14%) 1(3.57%)Type IIMyopic Astigmatism Hyperopic Astigmatism Mixed Compound AstigmatismLow High Low High Low High26-28 weeks 2 (8.33%) 14 (58.33%) 2 (8.33%) 3 (12.5%)28-30 weeks 3 (12.5%)30-32 weeks32-34 weeksTotal 19(79.16 %) 2(8.33%) 3(12.5%)Inclusion CriteriaNeonates who had laser treatment were includedin the study. Neonates with both Type 1 andType 2 (APROP) were selected for this study.Methods: our study included 90 Eyes of 45Patients of Which.Type 1 – 33 Patients – 66 EyesLaser DoneType 1 -- 15 Patients – 28 EyesType 2 -- 12 Patients – 24 EyesNo Laser only Changes: 18 Patients –36 EyesResults (Inference)1. Refractive errors measured upto 97.11% inneonates in our study.2. Initial refraction ranges from myopicastigmatism in majority cases to hyperopicastigmatism in fewer patients.3. Myopic Astigmatism seen in higher ranges inlaser treated eyes4. Type II ROP (APROP) showed a 100 %requirement of laser treatment in multiplesessions and refractive errors ranged frommyopic astigmatism (79.16%), Hyperopicastigmatism (8.33%), and Mixed compoundastigmatism (2.22%). The combined tally ofmyopic astigmatism was 91.36%.5. In Type I ROP prevalance of myopicastigmatism (68.18%), hyperopic astigmatism(25.75%), Mixed astigmatism (3.03%) and twoemmetropic patients in the laser treatedgroup.6. In non treated eyes refractive errors were seenin lower ranges especially low myopicastigmatism (50%), hyperopic astigmatism(22.22%), mixed compound astigmatism in(2.22%).7. In laser treated eyes prevalence of highmyopic astigmatism is more – MyopicAstigmatism (79.16%), hyperopicastigmatism (8.33%), mixed compoundastigmatism in (12.5%).8. Prevalence of higher refractive errors greaterin the lesser gestational age groups.9. Prevalence of higher refractive errors greaterin the lesser birth weight babies.10. Non treated eyes showed lower ranges ofmyopic astigmatism and hyperopicastigmatism.11. Pure myopia and hyperopia non existent inour series.DiscussionResults compared well with other studiesespecially that conducted at SNEC on AsianPopulation where they studied similar high ratesof myopia in ROP as compared to the no ROPgroup.

374 AIOC 2009 PROCEEDINGSAnother study by Verma et al showedpreponderance of myopia and anisometropia.Measurement and prescribing of refractivecorrection is highly essential in neonates at the1. Retrospective analysis of refractive errors inchildren with vision impairment.2. Du, Jojo W. and Schmid, Katrina L and Bevan.3. Optometry and vision science: Official publicationof The American Academy of Optometry 82 (9):pp.Referencessixth month to prevent future development ofstrabismus and amblyopia. This is a major aid todevelopment of physical and mental, motor andneuorosensory development of milestones in theinfants.807-816.4. Refraction and keratometry in premature infants :M X Repka in Kreiger Children Eye Centre.5. Refractive errors and strabismus in Asian infantswith and without ROP.AUTHORS’S PROFILE:DR. KASTURI BHATTACHARJEE: M.B.B.S. (’90), Guwahati Medical College, Guwahati;M.S. (’96). RIO, Guwahati; D.N.B. (’97) , National Board of Examination, New Delhi; F.R.C.S.(2002), Edinburgh, UK; Recipient of (i) Santavision Award in AIOC-2002, Ahmedabad,(ii) Col. Rangachari Award, AIOC-2008. Presently, Sr. Consultant, Academic Co-ordinator atShankaradeva Nethralaya, Guwahati.E-mail: kasturibhattacharjee44@hotmail.comComparison of Pentacam HR and TMS 4 Keratoconus ScreeningProgram In Screening Keratoconus – A Prospective StudyDr. Kasturi Bhattacharjee, Dr. Chandana Kakati, Dr. Harsha Bhatttacharjee,Dr. Ranjay Chakrabarty, Dr. B.M. Agarwal(Presenting Author: Dr. Chandana Kakati)Keratoconus is a non inflammatory ectaticcorneal disorder that presents later in thedisease process with central corneal thinning,corneal protrusion and progressive irregularastigmatism. 1 Classically the disease starts inadolescence and progresses through the thirdand fourth decades of life. 2Detection of keratoconus has received a greatdeal of attention in the last 15 years, concomitantwith the rise of refractive surgery, as keratoconusis a contraindication for refractive surgery.Various corneal topographic instruments areavailable which can aid in keratoconus detection,which includes TMS, Orbscan, Pentacam,Pentacam HR. Although all these instruments areeffective in detecting established keratoconus,most common dilemma arises in detecting inForme fruste keratoconus.The aim of this study is to evaluate therelationship between TMS 4 and Pentacam HR inscreening keratoconus.TMS 4 is a videokeratography instrument basedon placidos disc principle which graphicallyprocess the image reflected by cornea which iscaptured by CCD camera ,digitalizes andanalyses it by a computer. 3Pentacam HR is a new device that uses aScheimpflug camera. It produces a threedimensional image of the front and back surfaceof the cornea—a virtual picture of the anterioreye segment and the limbus-to-limbusmeasurement of corneal thickness 4Materials and MethodsThis is a prospective comparative study. Thestudy period was from 1st May07 to 30th April08. All total 81 eyes of 81 patients were includedin the study.There are 42 male and 39 female patients in anage range of 19-35 years. There are 37 right and44 left eyes.All the patients diagnosed to have keratoconusor suspected to have keratoconus by TMS 4 wereincluded in the study. However patients withany ocular pathology which mimic keratoconusin TMS4 keratoconus screening program but not

OPTICS / REFRACTION/ CONTACT LENSES SESSION375Table-1Subgroup Elevation map Front sagittal Centralanterior Posterior curvature corneal thicknessKeratoconus group 52.73±19.76 mm 52.76±46.5mm 58.26±12.24D 397±23µKeratoconus suspect group 22.04±5.14mm 42.68±15.5mm 49.86±3.45D 432±22µControl group 13.25±2.32mm 21.7±3.45mm 44.36±2.16D 524±38µsuggestive of keratoconus clinically, like patientswith contact lens warpage or corneal scar/opacity, dry eye etc was excluded from the study.A group of normal myopic patients wereincluded in the study as control group.Thus three group of patients were included, firstgroup keratoconus (group A, n=12), secondgroup keratoconus suspect (group B, N=27) andthird group normal myopic patients (group C,n=42).All patients had a thorough clinical examination.Corneal topography was done by both TMS 4and Pentacam HR on the same day.In TMS 4, keratoconus was diagnosed usingkeratoconus screening program using indexdefinition, Smolek and Klyce keratoconusseverity index and Klyce and Maeda keratoconussimilarity index 3 .In Pentacam HR, parameters used were elevationmaps (anterior and posterior), front sagittalcurvature, central corneal thickness and anteriorchamber depth. The parameters obtained in thesegroups by Pentcam HR were compared using t-test for difference in mean.ResultThe various finding obtained in Pentacam HR inall the three groups are shown in Table-1.The mean refractive error in these groups was asfollows, keratoconus group: -12.00±3.5 D spherewith -8.5±2.5 D cylinder, keratoconus suspectgroup: -9.75±1.5 D sphere with -5.25±1.5 Dcylinder and in normal myopic group: -6.25±3.5D sphere with -3.25±`.25 D cylinder.The mean anterior elevation in patients withkeratoconus group was 52.73±19.76 mm and inkeratoconus suspect group 22.04±5.14 mm whichis significantly different from normal group(P

376 AIOC 2009 PROCEEDINGSPentacam in detecting early keratoconus.However Pentacam HR is a very new device andvery little literature is available regarding itsefficacy. Hence a combined use of TMS 4 andPentacam HR can be a better alternative than1. Krachmer J H , Feder R S et all—Keratoconus andrelated non inflammatory corneal thinning—Surv.Ophthalmol 1984;28:293-322.2. Rabinnpwitz YS –Keratoconus—Surv. Ophthalmol1998;42:297-319.3. Corneal topography Corneal atlas—Lucio Bueretto4. Oculus Optikgerate—Pentacam.5. Wygledoska –Pramienska D et al—Use of TMS3keratconus screening program for keratoconusdetection—Klin Oozna 2000;102:237-40.Referencesusing Pentacam alone.TMS 4 and Pentacam HR in combination can bevery effective in detecting early keratoconuscases that are at potential risk for developingcorneal ectasia after refractive surgery.6. Corneal topography in wave front era--- MingWang , Tracy Swartz, chapter 18, page 2037. Susammah Quisling et all-Comparison of Pentacamand Orbscan 2z in posterior curvature topographymeasurements in keratoconus eye – Ophthalmology2006;113:1628-32.8. Bessho K Maeda N et all—Automated keratoconusdetection using data from anterior and posteriorcorneal surface, ARVO 2001, Abstract no –B819.AUTHORS’S PROFILE:DR. SHITIKANTHA PRADHAN: M.B.B.S (2003), S.C.B. Medical College , Cuttack , Orissa;M.S. (2nd year, 2009), V.S.S. Medical College , Sambalpur, Orissa.E-mail : dr_sitikant @yahoo.co.inProgressive Additive Glasses: Acceptance Versus Bifocals inVarious Professionals : A Cohort Study From A Tertiary HealthCare Centre, Western OrissaDr. Shitikantha Pradhan, Dr. Debnath Bhuyan, Dr. Gunasagar Das,Dr. Sharmistha Behera, Dr. Samir Mohapatra,Dr. H.Maruthi(Presenting Author: Dr. Shitikantha Pradhan), a natural age-related irreversibleP resbyopia4 optical failure, as a result of a gradualdecrease in accommodative amplitude, fromabout 15 diopters (D) in early childhood to 1 Dbefore the age of 60 years. Though notincapacitating, it prevents the luxury to performone’s effortless near tasks at a customaryworking distance. Patients with advanced orabsolute presbyopia may complain of blur atnear working distances as well as intermediatedistances, typically at distances of 40 to 100 cm.Our accommodative demands vary according tooccupation with variation in working distanceand nature of task. Here Progressive additionlenses(PAL) gives us a corridor of continuousfield of clear vision. Progressive addition lensesgradually increases in power as the line of sightcomes downward through the lens withoutvisible separating lines. Once the progressivelenses had been accepted, bifocals were generallyabandoned for good. This is mainly due to thequality of the progressive lenses, which favourprecise vision even in intermediate zones. Formost of the individuals who were previouslyfitted with reading glasses only, the demarcationline between the distant and near parts of thebifocal lens pose major problems ( 1 KRAUSE K etal.)Materials and MethodsThis prospective comparative study was donebetween March 2006 and March 2008 in theDepartment of Ophthalmology, at a tertiaryteaching eye care center in western Orissa to

OPTICS / REFRACTION/ CONTACT LENSES SESSION377evaluate acceptability of progressive additiveglasses over Bifocals. Cases were chosen fromamong all those aged 45-60 yrs using bifocals andreading glasses. They were counseled withregards to cost and benefit from PAL.841 casesusing bifocals and 101 cases using only readingglasses were included in the study. Professionalsrequiring variation in working distanceconstituted major group of the study. Patientsusing bifocals were further divided into fourgroups : Teachers 546(64.92%), Doctors142(16.88%), Bank officials 119(14.14%).computer professionals 34(4.04%). Excludedfrom the study were patients with astigmatismand those lost to follow up.All patients usingbifocals and only reading glasses were prescribedPAL. Compliance rate was recorded at least after6 weeks of exercise. Differences in opinion wastaken about general impression i.e cost andaesthetic aspect, clarity of vision, comfort leveland usage time was assessed by questioning thetotal time one used the aid per day.ResultsThere were total 3718 possible entrant over aperiod of two years, out of them 942 accepted thechallenge posed by their conditions, and wereprescribed PAL. Then proper instruction andadaptive training was given.93.10% professionals who were already usingbifocals found progressive additive glassesbeneficial: 502(91.94% of Teachers), 137(96.47%of Doctors), 113 (94.95% of Bankofficials),31(91.17% of computer professionals)and 6.90% who did not accept PAL was due tocost factor or previous adaptability to thebifocals. 68 patients (67.32%) using only readingglasses did not find any significant differenceowing to their limited duration of work at fixeddistance.Table-1: Percentage of professionals beneficiaryof PALProfessionals Total Beneficiary of PALTeachers 546 (64.92%) 502 (91.94%)Doctors 142 (16.88%) 137 (96.47%)Bank Officials 119 (14.14%) 113 (94.95%)ComputerProfessionals 34 (4.04%) 31 (91.17%)Total 841 783 (93.10%)Table-2: Comparision of acceptance of PAL inBifocals vs only Reading GlassesTotal Beneficiary of PALBifocals 841 783 (93.10%)Reading Glasses 101 33 (32.67%)DiscussionIn comparison to bi- or trifocal lens ,PAL gives usthe possibility to look at multiple workingdistances and no image jump, allowing for morevisual freedom. Additionally, the disturbingmerging lines of a bi- or trifocal lens do not exist.A progressive addition lens (PAL) is a seamlessmultifocal lens with the distance power at the tophalf of the lens and the power addition is locatedin the progressive zone, between the distance andthe near regions of the lens.. The key concept ofsuch a progressive addition lens is a so-calledumbilicus or vertex line. Along that line, whichmight be straight or curved, the basic powerchange of the lens takes place. Objects at differentdistances can thus be imaged according todifferent positions on the vertex line. There are awide variety of PALs available and with theincreasing trend of PALs becoming the lens ofchoice for many multifocal wearers, it isimportant for clinicians to make available theoption to accommodate patient's lifestyleactivities according to specific vocational andavocational visual requirements.1. Acceptance of PAL over bifocals:a comparativestudy. KRAUSE K et al. (02/12/1995) Jahrestagungder Berlin-Brandenburgischen AugenärztlichenGesellschaft,)2. RALF BLENDOWSKE, PhD, ELOY A. VILLEGAS,OD, and PABLO ARTAL, PhD, Laboratorio deReferencesOptica, Universidad de Murcia, Murcia.3. G. M. Fuerter, “Ophthalmic lens design withsplines,” SPIE Proceedings 1986;601,9-16.4. Beers APA, van der Hiejde GL. Age-related changesin the accommodation mechanism. Optom Vis Sci1996;73:235-42.

378 AIOC 2009 PROCEEDINGSAUTHORS’S PROFILE:DR. ARSHIA MATIN: M.B.B.S. (’95), M.L.N Medical College, Allahabad University; D.O.,(2000), A.M.U. Institute of Ophthalmology, Aligarh; M.S. (2003), M.L.B. Medical College,Jhansi. Presently in Private Practice in Jaipur.E-mail: matinarshia@yahoo.comOcular Axial Length in The Adult Population and Its CorrelationsWith Ocular and Systemic Parameters in Central India. TheCentral India Eye And Medical Study (CIEMS)Dr. Arshia Matin, Dr. Vinay Kumar Nangia, Dr. Nikhil Khanorkar, Dr. Monika Yadav,Dr. Ajit Kumar Sinha, Dr. Jost Jonas(Presenting Author: Dr. Arshia Matin)The axial length of the human eye is animportant indicator of myopia andhypermetropia. Myopia is characterized by agreater refractive error and axial length.Hypermetropia is characterized by smaller axiallength. Retinal pathologies are often associatedwith increasing axial length and myopia. Tallerchildren have been found to have eyes withlonger axial lengths, flatter corneas and myopictendency. 1 Singapore Chinese adults who weretaller had eyes with longer eyeballs, althoughthey did not show a relationship with myopia. 2Body weight has been associated with myopia inschool children 3 as well as with hyperopia inSingapore Chinese adults. 2Smaller axial lengths are associated with shallowanterior chambers and crowding of the anteriorsegment and considered to have a role in theevolution of primary angle closure glaucoma. 4,5It was the purpose of this study to assess the axiallength and to determine its ocular and systemicassociations in a population based study theCentral India Eye and Medical Study.Materials and MethodsThe Central India Eye and Medical Study(CIEMS) is a population based study conductedin a rural area about 40 kms from Nagpur. 6 In aninterim analysis, 3393 of 4291 subjects (responserate 79.1%) aged 30 and above were examined.The medical ethics committee of the Suraj EyeInstitute had approved the study protocol and allparticipants had given informed consentaccording to the declaration of Helsinki. Entirepopulation in the villages included in the studywas enumerated. The ophthalmic evaluationincluded visual acuity using ETDRS charts,refraction, slit lamp biomicrosocpy, applanationtonometry, gonioscopy, biometry, pachymetry,fundus examination and photography afterdilatation, and confocal scanning laserophthalmoscopy with the Heidelberg RetinaTomography II (software V 3). Medicalevaluation included pulse, blood pressure,height, weight, ECG, X-ray, complete bloodcount and serum and blood biochemistry,including kidney function tests. Intraocularpressure was recorded with the slit lampmounted Goldmann applanation tonometer.Ultrasound ocular biometry was done using theA Scan. A total of 3259 subjects were includedin the present investigation. Aphakes andpseudophakes were excluded from analysis. Themean age was 47.22±13.39 yrs, the mean axiallength was 22.67±0.85mm, mean IOP was13.91±3.22, and mean spherical equivalent was -0.21±1.51. There were 1514 males.Results: The ocular axial length showedsignificant correlations with male gender(P

OPTICS / REFRACTION/ CONTACT LENSES SESSION379Parameters Values Parameters ValuesAge (yrs) 47.22±13.39 Sph. Equ. (D) -0.21±1.51Height (cms) 156.84±9.36 IOP (mmHg) 13.91±3.22Weight (kgs) 48.69±10.43 Axial Length (mm) 22.66±0.85BMI 19.37±3.56 Axial length Males (mm) 22.94±0.84Systolic BP. (mmHg) 124.31±20.6 Axial Length Females (mm) 22.42±42Diastolic BP. (mmHg) 74.37±11.37were seen with IOP. In multivariate analysiswith axial length as dependant variable andintraocular pressure, age, gender, sphericalequivalent, systolic and diastolic blood pressure,height, weight and body mass index asindependent variables significant associationswere seen with male gender (P=0.004, 95%CI -0.23,-0.045), myopic refractive error (p

380 AIOC 2009 PROCEEDINGSAUTHORS’S PROFILE:DR. RITIKA SACHDEV: M.B.B.S. (2004), Lady Hardinge Medical College, Delhi University;M.S. (2008), Guru Nanak Eye Centre, Maulana Azad Medical College, Delhi University.Presently, Senior Resident R.P.Eye Centre. AIIMS, New Delhi.Refractive Changes in Keratoconus after C3RDr. Ritika Sachdev, Dr. Mahipal S. Sachdev, Dr. Charu Khurana(Presenting Author: Dr. Mahipal S. Sachdev)Corneal Cross Linkage is a novel modality fortreatment of progressive keratoconus andpost LASIK ectasia.Increased expression of collagenase 3, cathepsinK and human trypsin 2 leads to enzymemediated loss of collagen in keratoconus patients.Collagen cross-linkage increases the cornealrigidity and increases resistance againstcollagenase digestion.The crosslinking treatment not only halts theprogression of keratoconus but also inducesflattening of the steep cornea, though to varyingeffects in different patients.Collagen corneal crosslinking can be induced• Enzymatically,• With irradiation,• By means of aldehydes• Combination of UV radiation and photoactivationby means of riboflavin is the mosteffective and the least harmful procedureUVA light (370 nm)• Chiefly absorbed by cornea and crystallinelens (endogenous riboflavin and otherphotosensitizers leading to cross-linking ofcrystallins and sometimes cataract in the longterm)• UVA absorption in the cornea is increasedmassively during the cross-linking proceduredue to the photosensitizer riboflavin,resulting in a UVA-transmission of only 7%across the cornea• This intrinsic system protects the retina andfor this reason a UV absorber is usuallyincorporated into intraocular lenses.Our study was designed to document therefractive changes post collagen crosslinking inpatients with keratoconus and note adverserections of this therapeutic modality if any.Inclusion criteria• progressive keratoconus documented asincreasing myopia, astigmatism orkeratometry.• Vision with contact lenses or glasses is worsethan 20/20.• Corneal thickness greater than 400 microns atthe thinnest point. (hypotonic riboflavinsolution was used in cases with cornealthickness less than 400 microns).Exclusion criteria• PregnancyProcedureThe epithelium was scraped off and riboflavindrops were instilled topically over half an hour,following which the patient was treated with UV-A radiation for 30 minutes.Results• 26 cases of keratoconus• Age Range – 13-33 yrs• 9 Females, 17 males• Keratometry varying between 42.3D – 67.6D• Sim K astigmatism varying between 1.60D-14.2D• Overall flattening of corneal contour(Reduction of Sim K astigmatism between0.2D-6.9 D)• Effect most apparent on the anterior surface(ABFS)• Overall reduction of 1.0 D-7.0 D ofastigmatism noted in our patients at 1 month.Improvement In Bcva• By 3 lines in 5 eyes• By 1 line in 9 eyes

OPTICS / REFRACTION/ CONTACT LENSES SESSION381• Remained stable in restAdverse effects: Haze was apparent in 18 of thepatients though it was not associated withdecreased BCVA.No adverse changes were noted in the crystallinelens or the retina.AUTHORS’S PROFILE:DR. RENUKA SRINIVASAN: M.B.B.S. (’75), Lady Hardinge Medical College, DelhiUniversity; M.S. (’81), JIPMER, Madras University. WHO Fellowship in oculoplasty- WilmerInstitute John Hopkins; Commonwealth Fellowship Refractive surgery St Thomas Hospital,LondonPresently, Director Professor, JIPMER , Pondicherry .E-mail: renuka_oph@yahoo.comRefractive Outcome in Preterm and Term InfantsDr. Renuka Srinivasan, Dr. Vanuli Agarwal, Dr. Anjali A.(Presenting Author: Dr. Renuka Srinivasan)Refractive errors are common following bothfull term and preterm birth. Full termneonates usually have high levels of hyperopiaand astigmatism which reduce rapidly duringthe first year of life. Ingram et al found thisprocess, known as emmetropialisation, to becomplete in 82% of full term infants by 12 monthsof age. 1 Preterm infants tend to be more myopicand astigmatic at birth than full term infants.Emmetropialisation gradually occurs in theseinfants also. Prematurity (or low birth weight)has an impact on refractive development evenwhen ROP is absent or clinically undetectable.Some authors have reported that infants who donot develop ROP demonstrate a more normalpattern of refractive development. Others findthese infants have an increased risk fordeveloping significant refractive errors, inparticular myopia.This study aims to comparethe progression of refraction in term and preterminfants and assess their emmetropialisation.Materials and MethodsThe study was conducted in the Departments ofOphthalmology and Pediatrics, JawaharlalInstitute of Postgraduate Medical Education andResearch (JIPMER), Puducherry. Preterm infantsadmitted in the Neonatal Intensive Care Unit,Department of Pediatrics between August 2005and September 2006 were enrolled in the study.Term infants were those delivered in JIPMERduring the same duration. Informed consent wasgained from the parents before enrolling theinfants in the study.120 eyes of 60 infants were included in the study.Subjects were 30 preterm infants born at less than37 completed weeks of gestational age and 30term infants with gestational age more than 37completed weeks.The infants were examined by torch light to ruleout any anterior segment abnormality. Mydriasisand cycloplegia were achieved using 0.5%tropicamide and 2.5% phenylephrine eye dropsinstilled twice 10 minutes apart in both eyesIndirect ophthalmoscopy performed on all eyesfor detailed fundus evaluation especially as ascreening for Retinopathy of Prematurity.Retinoscopy was performed in both eyes at adistance of 1 meter using streak retinoscope. Theretinoscopy was repeated at an average of 20months of age. The refractive error was recordedas the Mean Spherical Equivalent (MSE).Myopia was defined as refractive error less than0D. A refractive error of more than -3D wasconsidered as high myopia. Hypermetropia wasdefined as refractive error more than 0D, an errormore than +3D considered as high hypermetropia.Astigmatism more than 1D was consideredsignificant and a difference between the two eyesgreater than 1D was labeled as anisometropia.Unpaired t test was used to compare the meanspherical equivalent in term and preterm infantgroups at various periods of follow up. A pvalue of

382 AIOC 2009 PROCEEDINGSinfants were normal except for one infant whohad mild corneal haze at birth. This cleared bythe 40th week PCA follow up. The anteriorsegment evaluation in term infants did not showabnormality in any of the subjects. There was noRetinopathy of Prematurity in any of the eyes ofpreterm infants. Fundus evaluation in terminfants did not reveal any abnormality in any ofthe subjects.At birth, the mean refractive error of term infantswas +2.58D and that of preterm infants was+0.59D. At the end of the follow up period, themean refractive errors were +0.5D and -0.2D forthe term and preterm infants respectively.10 out of 30 preterm infants (≈33%) were myopicat birth and the rest hypermetropic. This myopiaranged from -0.25D to -3.5D. The mean myopiawas -1.67 D with standard deviation of 1.14. At20 months of age, the number of myopic childrenwas the same. The average myopia was -0.76Dwith standard deviation of 0.58, and ranged from-0.25D to -2.0D. In the term group 2 out of 30 hada myopic refraction ranging from -0.5D to -1.5Dand the myopic state in both had regressed by 20months.Hypermetropia ranged from +0.25D to+3.5D andfrom +0.5D to +6.5D in preterm and term infantsrespectively at birth; with the average hypermetropiabeing +1.13 D in preterm, and +2.83 Din term. The mean hypermetropia at 20 monthswas +1.34D with standard deviation of 0.47 andranged from +0.50D to +2.00D in the preterm.DiscussionRefractive outcome was assessed for preterm andterm infants at birth and till 20 months of age.The mean refractive error showed a shift from+0.59D to –0.20D in the preterm group and from+2.58D to +0.50D in the term group during thestudy period. K J Saunders et al in their study of59 preterm infants found a mean MSE of 0.47 D ±2.36 at birth (38), which is comparable to ourresults (2). However, at term age, they found amean MSE of 0.87 D ± 1.72, which is less ascompared to our study. This difference infindings could be due to the patientcharacteristics in this study, where the meangestation age was 40.3 weeks, and birth weight3.47 kg, while in our study, the mean gestationage was 39.3 weeks, and birth weight 2.89 kg.Ton Y et al found a mean MSE of 1.24 D in infantsaged one month or less. 3 The difference in theMSE could be due to their age at examinationwhich is one month or less, starting from aminimum of two weeks.33% of preterm infants were seen to have myopiaat birth, with the number remaining same evenby 20 months of age. In a study of 50 preterminfants, Page GM et al showed incidence ofmyopia of about 18% at birth, which increased to38% by two years of age 4 ; but this could be due toa high incidence of ROP in their cohort (>50%),as well as the low gestational age of the subjectsat birth. Holmstrom M et al in a study on 248preterm infants saw an incidence of myopia of8% at 6 months and 10% at 30 months. 5 Thesefigures show a lesser incidence than our study. Apossible reason could be the larger study populationin this study, as well as a differenrt demographicprofile of the population under study.Amongst Asian studies, Verma M et al studied50 preterm infants, and have showed that at 1year of age, 64% of the babies had normal visionwhile incidence of myopia and hypermetropiawas 16% and 20%, respectively. 6 While Kim JYet al have shown in a study of 99 prematureinfants at 6 months of age that the incidence ofmyopia in premature infants without ROP was36.3%, and the degree of myopia was low (-1.76D), which is similar to our results. 7In our study, the incidence of hypermetropia interm infants is seen to be 90%, with 30% infantshaving significantly high hyperopia. Thisincidence of high hypermetropia was seen toreduce to none by the age of 20 months. A studyby Mutti D O et al reports the incidence ofhyperopia more than +3.00 D to be 25% inneonates. 8 By nine months, this incidence hasbeen reported to be 5.4%. The mean value ofhypermetropia in our study reduced from 2.83 Dat birth to 1.85 D at six months of age. Edwards Mand Zonis S also show a progressive reduction inthe level of hypermetropia with age in theirstudies. 9,10 However, Wood and Gwiazda in theirstudies saw an increase in hyperopia in the initialsix months followed by a fall in the refractiveerror. 11,12High hypermetropia (>+3D) was seen in 15.4%of preterm infants at birth by K J Saunders et al(2), and in 13.4% of right eyes and 12.1% of lefteyes at 3 months of age by Holmstrom G et al. 5

OPTICS / REFRACTION/ CONTACT LENSES SESSION383Incidence of high hypermetropia in our studywas 3.33% at birth, and nil at 20 months of age.It appears that the myopia in the preterm infantstend to persist for a longer time than previouslyreported though at a smaller degree. This couldbe because of the slower rate of growth seen inIndian children when compared to the west andalso because of the small sample size which maynot have represented the general population. Alarger study in the Indian population, with asuitable long term follow up period may berequired to reach a definite conclusion.The refractive status of the preterm infants issignificantly different from the term infants with1. Ingram RM, Walker C, Wilson JM, Arnold PE, DallyS. Prediction of amblyopia and squint by means ofrefraction at age 1 year. Br J Ophthalmol 1986;70:12-5.2. Saunders KJ, McCulloch DL, Shepherd AJ,Wilkinson AG. Emmetropisation following pretermbirth. Br J Ophthalmol 2002;86:1035-40.3. Ton Y, Wysenbeek YS, Spierer A. Refractive error inpremature infants. J AAPOS 2004;8:534-8.4. Page JM, Schneeweiss S, Whyte HE, Harvey P.Ocular sequelae in premature infants. Pediatrics.1993;92:787-90.5. Holmstrom G, el AM, Kugelberg U. Ophthalmologicalfollow up of preterm infants: a populationbased, prospective study of visual acuity andstrabismus. Br J Ophthalmol 1999;83:143-50.6. Verma M, Chhatwal J, Jaison S, Thomas S, Daniel R.Refractive errors in preterm babies. Indian Pediatr.1994;31:1183-6.7. Kim JY, Kwak SI, Yu YS. Myopia in prematureWe have come a long way in the field ofOphthalmology, whether in CataractSurgery, Retinal sub-specialty or even Optics andRefraction. Use of additional measures to seethings more clearly goes way back to 300 BC,probably originating in China. Eye glasses wereinvented in Florence, Italy in 1280 but it tookseveral decades before an American, BenjaminFranklin invented Bi-focals in the year 1760. Sincethen a revolutionary change was ushered in, asfrom mere single vision glasses like Lorgnette,monocle now there is a whole range of Opticalgadgets from bi-focals to multifocals, fromReferenceshigher incidence of certain refractive errors.Preterm infants have a higher chance ofdeveloping a myopic refraction than term infants.The myopia of preterm infants was found toresolve slower than previously reported.Though these errors show a general trendtowards normalization with the growth of theinfant, their sequelae and impact on vision laterin life can not be predicted with the study.A longer follow up for infants with residualrefractive error is vital to detect and immediatelycorrect any refractive error that may causediminished vision and make the child susceptibleto development of amblyopia.infants at the age of 6 months. Korean J Ophthalmol.1992;6:44-9.8. Mutti DO, Mitchell GL, Jones LA, Friedman NE,Frane SL, Lin WK, et al. Axial growth and changesin lenticular and corneal power duringemmetropization in infants. Invest Ophthalmol VisSci 2005;46:3074-80.9. Edwards M. The refractive status of Hong KongChinese infants. Ophthalmic Physiol Opt 1991;11:297-303.10. Zonis S MB. Refractions in the Israeli newborn. JPediatric Ophthalmol 1974;11:77-81.11. Wood ICJ HS. Refractive findings of a longitudinalstudy of infants from birth to one year of age(abstract). Invest Ophthalmol Vis Sci 1992;32:971.12. Gwiazda J TFBJHR. Emmetropization and theprogression of manifest refraction in childrenfollowed from infancy to puberty. Clin Vis Sci1993;8:337-44.Optical Dispensing — New ScenarioDr. Ashwini Kumar(Presenting Author: Dr. Ashwini Kumar)glasses to no glasses i.e. Lasik and now PhakicIOLS. Now glasses are available as per individualneeds, e.g. Computer glasses for softwareprofessionals and to enhance our appearance aswell.Current scenario: Single Vision, Bi focals, Trifocals, Multifocals, Computer glasses, AsphericLenses, Sun glasses. Three types of bi focals areavailable: Kryptok, Univis D, and Executive.Kryptok is the most common as well aseconomical, though some complain of opticaljump. Executive type has no jump but then it iscosmetically unacceptable. Univis D is

384 AIOC 2009 PROCEEDINGStechnically the best as it has reduced optical jumpand prism effect, but is expensive.Tri focals are thicker, usually available in hardresin and polycarbonate. As the name suggests ithas three zones: Near, Intermediate, Distance.Added segment provides clear vision at arm'slength distance.Aspheric lenses: It has cosmetic benefits as iteliminates the bulgy appearance of strong pluslenses (far sighted corrections) and greatlyenhances appearance of finished eyewear. It ispositioned closer to the face leading to lesser eyemagnification for farsighted corrections and less"small eyes" look in nearsighted corrections.The latest entrants are Multifocals whereintermediate distance is covered, as well andthese are available in different materials. Lots ofcompanies have come up like Seiko,Roddenstock, Sola, Zeiss, Nikon and each onehas some special characteristics. Multifocalscome in two varieties, popularly known as Hardand soft. Hard type has a narrow intermediatezone which leads to more peripheral astigmatismof around +/-2. Soft type has broaderintermediate zone and hence lesser peripheralastigmatism.GT2 by ZEISS: GT2 is virtually distortion-freeabove the 180° line for truly satisfying distanceand peripheral vision. Its large near zone iscarefully positioned for the wearer's preferredeye rotation while reading. GT2's optimizedcorridor allows for up to 50% more near utilitythan several of today's leading progressives insmaller frames. The progression of power andastigmatism has been carefully managed forexcellent control of wave front aberrationsthroughout the lens.SOLA Compact ULTRA: It has less skewdistortion, greater control over astigmatism andclaims ultra performance even in ultra smallframes because of its soft and smooth geometry.Varilux: It has a smooth gradual transitionalong with increased field of vision.Nikon: Due to its asymmetrical design, theselenses offer more than 30% widened near vision.Its speciality being it allows the reader to see theentire two pages of an A4 magazine at one go.Special eye wear includes Sports glass made ofPolycarbonate and Computer glass which hasless electromagnetic interference and includesspecial filters and anti-reflection coatings.Lens materials: CR39 - Plastic: Conventionalhard resin lenses are half the weight of glasslenses and can be tinted to all colors. Thoughmore scratch prone than glass, it is more impactresistant and optional scratch protection may beapplied.POLYCARBONATE: These are the most impactresistant lenses, probably the lightest and mostcomfortable.GLASS: It absorbs UV light and offers superioroptics, though falling in popularity in recentyears. Apart from that in extremely highprescription, glasses are more suitable. Somespecial kind like Borosilicate crown glasses areused in Telescopes and binoculars and Fluoritecrown glasses are used in high end cameras.VARIANTSHigh index: These are slimmer and hence moreattractive, lighter in weight and shatter resistant.Absorb all harmful lights but have higher levelof chromic aberrations due to their lower Abbevalue.Transitions: Darkens as one goes from indoorsto outdoors - begin as one color and changes to atotally different one when activated: teal blueturns to green, yellow becomes orange and redtransforms into purple. These are available inglass and hard resin as well.Photochromics: Earlier photochromics wererestricted to only glass lenses - but now photochromatic plastic, high index glass andpolycarbonate lenses are available. Whole lenschanges when exposed to light. In a particularlystrong prescription the strongest, thickest part ofthe lens will be darker than the thinner parts,depending on amount of ultraviolet light -changes from clear eyeglass to dark sunglasslenses in 60 seconds.Sun glasses: 100% UV protection, or labeledUV400. Lens color depends on utility: gray forgeneral use, brown for daytime, yellow andamber for low light and light blue or pink fordriving or sports. Polarized lenses which reduceglare are a good option.Lens coatings and treatment: Anti-reflectivecoating: Provides great safety benefit whendriving at night and effective in eye fatigue. Thiscoating is used for microscopes and cameralenses as well.Tints: Can be applied on plastic as well as glass

OPTICS / REFRACTION/ CONTACT LENSES SESSION385and can be procured in almost any color ofrainbow.Mirrored /Flash coating: Purely cosmetic andhighly reflective, creates no difference in vision.Scratch resistant coatings: No lens material isscratch proof. Light weight plastic lenses aremore easily scratched. Here it is treated front andback with a clear hard coating, which makes itmore resistant to scratching.Frame materials: Plastic - Zyl or acetate - getsbrittle and discolors with age and skin fluids.Nickel silver - Used in cheaper frames and easyto coatMonel - Better quality frames, less likely to wearor chip off.Titanium - Very light, strong, resists corrosion,great for hot and humid climate and ishypoallergenic as well.Stainless steel - Made of chrome and Iron,springy, resists corrosion, cheaper alternative totitanium and less hypoallergenic.Memory steel - Made up of Titanium and nickelalloy and it retains its original shape and lightweight, apart from being corrosion resistant.Lenses of TOMORROW:Trivex: Triple combination of superior optics,1. AAO 2000;129:427-35.2. Arch Ophthalmology 2005;123:977-87.To calculate the dioptric power of IOL, thesurgeon can choose several proven formulas,all of which are dependent on multiple variablessuch as A constant, keratometry measurements,axial length measurements. Keratometry doesnot play as critical a role in the most commonlyused SRK formula as does the axial length. Axiallength is generally obtained through ultrasonicReferencesimpact resistance and ultra weight. Good optionfor rimless frames due to its resistance to crackingaround the drill holes. It has good UV blockingproperties and can be easily tinted as perpurpose.Excelite TVX: Apart from aesthetic thinness,these lenses have remarkable optical clarity,astounding impact and chemical resistance,incredible tensile strength with added benefit ofbeing light weight.Phoenix: It provides 100% UV protection, is 6times stronger than standard plastic and twicescratch resistant as compared to polycarbonates.Apart from being chemical and heat resistant, itis 19% lighter than standard plastic and 8%lighter than polycarbonates.Low vision aids: Optical and Non-opticalDevices.Optical devices: Magnifying Spectacles (High+),Hand Magnifiers, Stand Magnifiers, Telescopes,Bioptic Telescopes.Non-optical devices: Typo scope , Felt tippedPens, Good light on object, Bold lined paper ,Writing guide, Reading stand , Adjusting light/glare, Space with less clutter, Lighting and lamps.Newer ones: Computer based systems, electrooptical devices, independent living devices.3. Bowers et al: IOVS 2005;46:66-74.4. Medline 32:189-98.Comparison of Primary Pediatric Posterior Chamber Lens(PCIOL) Power, Estimated From The Aphakic Refraction Alone(With Assumed Average Keratometry Value of 44 Dioptres)Versus Calculation Based On Preoperative Ultrasonic biometryDr. Usha Kaul Raina, Dr. Sonam Angmo Bodh, Dr. Basudeb Ghosh,Dr. Meenakshi Thakkar, Dr. Vinod Aggrawal, Dr. Vasu Kumar, Dr. Neha Goel(Presenting Author: Dr. Usha Kaul Raina)measurements. An error of 1mm in AL canproduce a post-operative refractive error of 2.5D.Ultrasonic axial length measurements are proneto error in children because of increased cornealelasticity, differing ocular tissue viscosity, oculardimension that do not correspond to the adultdimension assumed by theoretical IOL formulasand patient cooperativeness. However axial

386 AIOC 2009 PROCEEDINGSlength can also be estimated from intra-operativeaphakic refraction. 5 Keratometry can be assumedas an average value (because the effect of varyingkeratometry values on predicted pseudophakicrefraction is small if an eye’s aphakic refractionand hence the axial length is known). 3No study has been done till date regardingprimary IOL power estimation in children usingthe aphakic refraction technique. Thus weconducted a study to see the refractive outcomein children in whom primary IOL powercalculation was done on the basis of calculatedaxial length from intraoperative aphakicrefraction and using an average keratometryvalue.Materials and MethodsWe took 15 eyes of congenital, developmentaland traumatic cataract between 5yrs-10yrs agegroup who underwent primary PCIOLimplantation with hydrophobic foldable acryliclens after an informed consent. Biometry wasdone using P-axial ophthalmic ultrasound tocalculate axial length of eye ball and calculationof IOL power. Bausch and Laumb keratometerwas used for keratometry measurements.IOLpower was calculated using modified SRK-IIformula based upon preoperative keratometryand axial length. Intraoperative aphakicrefractions were done using hand held autorefractometer.The axial length of each eye wasestimated from intra-operative aphakic refraction(spherical equivalent) using formula given byKhan.A. 3 All calculations were done usingmicrosoft Excel.V2003. The estimated axial lengthwas used in SRK-II formula with an averagekeratometry value of 44 to predict the power ofPCIOL for emmetropia. For each eye twoprimary PCIOL values were compared. The twomethods of PCIOL prediction were then used topredict the expected pseudophakic refraction forin-the-bag placement of PCIOL actuallyimplanted. In all patients ultrasonicallycalculated PCIOL implanted.ResultsResults of study is summarized in Table-1The mean patient age was 7.8 yrs. The estimatedPCIOL values (mean 23.84, 95% confidenceinterval (CI) 1.77) and the calculated PCIOLvalues (mean 22.84, CI 2.15 D) were significantlydifferent (mean difference 1.00 D, CI 1.50).Themaximum difference was 4.4D and minimumdifference was 0.30D. Postoperativepsuedophakic refractions were analysed in allpatients. Comparison of expected pseudophakicrefractions were done with actual pseudophakicrefraction. Although expected psuedophakicTable-1No. Age Pre-op Pre-op Pre-op Intra-op Intra-op Intra-op Unaided Visual acuity(yrs) Kerato calculated estimated sph Eq estimated estimated Post-opmetry Axial PCIOL Axial PCIOL refractionlength power (D) length power (D)1 8 40.5/40.5 22.58 25.5 14.5 20.67 27.10 6/6,+0.25/-1@10=6/62 10 42.5/42.5 23.04 23 10 23.16 20.87 6/9, -0.75/-1.5@30=6/63 9 41.8/39.9 22.16 25.65 11.75 22.13 23.45 6/9, -0.5/-0.5@10=6/64 6 44/42 21.2 26.6 11.5 22.39 22.81 6/6 0.75dc@6o=6/65 10 43.2/42.2 22.98 22.95 9.5 23.70 19.54 6/18,+0.75/-1.75@120=6/66 10 42/42 23.59 21.74 12.5 21.64 24.69 6/24, +1.25/-0.5@10=6/67 8 40.6/40.6 23.18 2O.88 14.5 20.67 27.10 6/12, +2/-1.75@90=6/98 9 41.8/43.8 21.10 28.92 13.5 21.15 25.91 6/18,-1.75/-.75@10=6/19 9 44/44 20.28 29.11 16.5 19.52 29.97 6/12,-+0.75/-1.25@90=6/610 8 42.5/42 21.55 27.3 13.5 21.15 25.91 6/18,-1.75/-1.5@180=6/911 5 44.2/42.5 23.52 20.26 10 23.16 20.87 +0.5/-1.75@10012 7 44.5/42.5 24.48 17.49 7 25.37 15.35 6/18,-1/-1.5=6/1813 8 41/39 22.93 24.88 10.5 22.90 21.53 6/24,-1.75/-3.5@180=6/914 4 44/44 23.62 19.75 7 25.37 15.35 -6DS15 6 38.6/37 25.92 19.14 9 23.97 19.54 6/24,+.75/+2@90=6/6

OPTICS / REFRACTION/ CONTACT LENSES SESSION387refractions differed from actual psuedophakicrefractions in both the groups, the expectedpsuedophakic refraction values predicted fromestimation method were found to be closer toactual pseudophakic refraction than thosepredicted by calculation method.DiscussionUltrasonic axial length measurements are proneto error in children because of increased cornealelasticity, (and thus increased potential forcorneal compression), differing ocular tissueviscosity (potentially resulting in an actual speedof sound different from what is assumed by theultrasound unit) and ocular dimension that donot correspond to the adult dimension assumedby theoretical PCIOL formulas and patientcooperativeness. When carried out underanaesthesia, axial length measurements are proneto error because they are made without the1. Hug T. Use of the aphakic refraction in intraocularlens (IOL) power calculations for secondary IOLs inpediatric patients. J pediatr Ophthalmols trabismus2004;41:209-11.2. Binkhorst RD. The accuracy of ultrasonicmeasurement of the axial length of the Eye.Ophthalmic Surg. 1981;12:363-65.3. Khan A. Pediatric secondary intraocular lensestimation from the aphakic refraction alone:comparison with a standard biometric technique. BrJ Ophthalmol 2006;90:1458-60.Referencesguidance of a fixating patient. Thus primaryfocus of our study was to derive a method of IOLcalculation in children that would not requireultrasound measurement. An alternativemethod for axial length and PCIOL powerestimation is intraoperative aphakic refractionwith an arbitrary keratometry value. In our studywe found that keratometry does not cause errorin IOL power calculations unless it is very steepor flat. PCIOL power estimated from aphakicrefraction gives values closer to values obtainedfrom ultrasonic method. In most of the patientswe found that expected pseudophakic refractionspredicted by estimation method were closer toactual pseudophakic refraction than thosepredicted by calculation method. Although boththe methods are prone to error,intaoperativeaphakic refraction is an alternative method forPCIOL power estimation especially if biometry isunavailable.4. Weinstein GW, Baum G, Binkhorst RD. Acomparison of ultrasonographic and opticalmethods for determining the axial length of theaphakic eye. Am J Ophthalmol 1966;62:194-201.5. Krag S, Olsen T. Secondary IOL power calculation:a comparison of an optical and a biometric method.Acta OphthalmoI 1991;9:625-29.6. .Costas S. Intraoperative retinoscopy: A way toachieve emmetropia in cataract surgery. J CataractRefract Surg 2005;6:1258-60.AUTHORS’S PROFILE:MANISHA CHHABRA ACHARYA: M.B.B.S. (’99), J.N. Medical College, Aligarh MuslimUniversity; M.S. (2003), Institute of Ophthalmology, Aligarh Muslim University; D.N.B (2004).Presently, Consultant, Cornea Services at Dr. Shroff’s Charity Eye Hospital, Daryaganj, NewDelhi. Recipient of Best Paper Award-- Cornea Session in DOS 2005.Contact: 9810136933; E-mail: manisha28dr@yahoo.comDemographic Profile and Visual Rehabilitation of Patients withKeratoconus Attending Contact Lens Clinic at A Tertiary Eye CareCentreDr. Manisha Chhabra Acharya, Dr. Tarannum Fatima, Dr. Umang Mathur,Dr. Amit Agarwal, Dr. Prasanjeet Barua(Presenting Author: Dr. Manisha Chhabra Acharya)Keratoconus is a bilateral, asymmetric,chronic, progressive ectasia of the corneacharacterized by steepening and distortion of thecornea, thinning of the apical cornea, andsometimes corneal scarring. Keratoconus affectspeople in their prime earning years and

388 AIOC 2009 PROCEEDINGSprofoundly affects their lives. The majority ofkeratoconic eyes in Asian-Indian patientsdemonstrate the severe stage of the disease by thesecond decade. 1 Patients experience distortedvision that worsens with the disease progression.Although spectacles help in early stage, mostpatients require contact lenses for visualrehabilitation. Several rigid contact lens fittingsets available have their origin in one of the threefitting philosophies: apical clearance, three-pointtouch, and apical bearing. 2,3,4 With no acceptedstandardized protocols,the 'three-point-touch'approach is now the most widely acceptedcorneal lens fitting philosophy in clinical practice 3Custom-designed rigid lenses are the newoptions for patients with unacceptable fit. 5,6,7 Thecontact lenses fitting in keratoconus becomesdifficult and less successful as the diseaseseverity advances.Most patients eventually undergo cornealtransplantation in one or both eyes. Contact lensintolerance and unacceptable fit is the mainindication for keratoplasty 8,9 Studies to date havereported >90% graft survival data between 5 and12 years from the time of transplant. 10,11 Howeverreports of late recurrence of keratoconus havebeen described from 7 to 40 years afterkeratoplasty 10,11,12 with a mean latency of roughly17 years. 13 Many of these cases are supported byhistological confirmation. 10,13 This seemsimportant given the fact that most keratoconuspatients receive transplants at a relatively youngage. Therefore contact lenses seem important indelaying PK to a later age especially in Indiawhen keratoconus manifests at an earlier age ascompared to the western countries. 1 Furthermorevisual rehabilitation is often slow andcomplicated. 9 Even Keratoconus eyes treatedwith corneal transplants frequently need contactlenses for visual rehabilitation.This study evaluates the demographic profile ofkeratoconus patients in India and their functionaloutcomes with various modalities of contact lensmanagement in a tertiary eye care center.Materials and MethodsThe data of all patients with keratoconusattending the contact lens clinic of Dr Shroff’sCharity Eye Hospital, Delhi between Jan2007-Dec2007 was analyzed.The patients were included in the study if theyhad unilateral or bilateral keratoconus. Theexclusion criteria for study comprised of patientswith associated ocular disease like glaucoma,cataract, retinal pathology or any systemic illness.Clinical records were retrospectively analyzedfor demographic aspects which included age andgender, systemic disease association, duration ofthe disease and previous contact lens history.Clinical parameters studied included unaidedvisual acuity, best corrected visual acuity withspectacles and with contact lenses. The visualacuity was assessed using Snellen acuity chart fordistance and near and was then converted to logMAR values. Detailed slit lamp examination wasdone. Lens centration and movement was notedand the type of fit recorded. Values ofkeratometry, corneal topography andSchirmer/test were noted.The grading of keratoconus based onkeratometry was done for every patient . Gradingbased on keratometry was as follows:Mild Keratoconus 52 D in 1 orboth meridians. Severe keratoconus >62 D in 1or both meridians.The contact lens choice included conventionalRGP contact lens, Rose K contact lens and Bostonscleral contact lens. The fit assessment ofconventional RGP lens trial and Rose K lens trialwas done by evaluating the dynamic fit and staticfit by fluorescein staining. The three point touchapproach was followed as standard for allpatients.The design and fitting procedure of ScleralContact Lens was based on observing thevascular compression patterns of the bulbarconjunctiva created by a series of diagnosticlenses of different haptic designs and diametersto avoid circumferential compression that wouldobstruct the functionality of the venting channels.Follow up information was also recordedespecially if they had to undergo penetratingkeratoplasty during the study period.ResultsThe total number of new patients seen in contactlens clinic during the one year study period was856. The incidence of keratoconus in patientsattending contact lens clinic was 8.9%.Seventy-

OPTICS / REFRACTION/ CONTACT LENSES SESSION389seven patients with keratoconus (142 eyes) wereexamined during the study period. Out of the 77patients, 49 (63%) were males and 28(37%) werefemales. The age group ranged from 15years-52years (median age 24 years).Keratoconus grading based on keratometry wasdone. 20 eyes (14.4%) were diagnosed to havemild keratoconus, 51eyes (36.7%) had moderate,45(32.4%) had advanced and 23 eyes (16.6%) hadsevere keratoconusThree patients had undergone Penetratingkeratoplasty in other eye and 1 patient requiredrigid gas permeable lens postoperatively for highirregular astigmatism and 1 patient underwentoptical PK during the study period.One hundred and thirteen eyes (79.5%) werevisually rehabilitated with conventional RGPlenses while 29 eyes (20.4%) fitted best with RoseK contact lenses and in 1 patient Boston sclerallens was given in both eyes.With glasses the visual acuity was 6/9(0.18logMAR) or better only in 43.6%.Best corrected No % Cumu- Cumu-Visual acuity of lative lativewith glasses eyes %6/9 and mor 62 43.6 % 62 43.6%6/12-6/18 38 26.7% 100 70.4%6/36-6/24 28 19.7% 128 90.1%6/60 or less 14 9.9% 142 100%With contact lens wear, visual acuity improvedto 6/9 (0.18logMAR) or better in 90% (129eyes)and all improved to 6/18 (0.48 logMAR) or betterVisual No of % Cumu- Cumuacuityeyes lative lative %6/9 and more 128 90% 128 90%6/12-6/18 13 9% 141 99%6/36-6/24 1 0.7% 142 100%6/60 or less 0 0 142 100%DiscussionKeratoconus is a condition in which the corneaassumes a complex irregular curvature caused bycentral corneal thinning. The abnormaltopography of the cornea in combination withcentral corneal scarring results in an impairedvisual acuity. 14 Even in mild cases spectacles donot correct vision adequately. 14 Hence contactlenses remain the mainstay of treatment in thesecases until intervention is required. Though theresults of PK are very favorable in cases ofkeratoconus yet studies have shown that evenafter surgery 40-50% of the patients requirecontact lenses. 9Study by Saini et al showed that the mean age forkeratoconus in India was 20 years 1 ; we found asimilar result with keratoconus affecting youngadults at a mean age of 24 years. This can beconsidered early in comparison to the westernstudies where they found that the mean age atpresentation was 28.6 years. Further 57% (44patients) of the cases at our clinic were previouslydiagnosed cases of keratoconus indicating thatthe disease process must have started earlier.Pearson and associates 12 concluded thatcompared with Caucasians, there is a fourfoldincrease in incidence of keratoconus in Indiansliving in Midland, United Kingdom.The authorsspeculated that this difference between Asianand white patients may reflect geneticdifferences. This data also documents overallaverage age at presentation of only 20.2 ± 6.4years.Regarding gender ratio ,male preponderance hasbeen reported with an average male to femaleratio of 3:216. This is similar to our study ratio.Good visual outcomes have been reported inkeratoconus with contact lenses, In the baselinefindings in CLEK study 17 , the visual outcomeswith patients fitted with RGP was 6/12 or betterin 77.9% eyes. In another study by Dada et al 18visual acuity was 6/9 or better in 65.03% of thepatients. In our study we found a better visualoutcome than the previous studies. In our groupthe BCVA with contact lenses was 6/9 or betterin 90% of the eyes. This brings the importance ofchanging fitting philosophy and the newerdesigns and advancement in materials of contactlenses improving the visual outcomes andpatient comfort.The most common problem with conventionalRGP contact lens fitting in advanced keratoconusis a high riding or a low riding lens which causesforeign body sensation in the eye leading to lensintolerance. Rose- K lenses because of theirunique design improve the fitting thereforeimproving the tolerance. In a study by Jain et al 16in 2006, they found that 97% of the patients couldbe fitted successfully with Rose –K lenses withgood visual outcomes. Visual outcomes was 6/12

390 AIOC 2009 PROCEEDINGSor better in 94.7% of the eyes. This result is similarto ours where we found visual acuity of 6/12 orbetter in 93% (27 out of 29 eyes) eyes.Recently Betts 20 and colleagues reported bettervisual performance and lens comfort with theRose-K design rigid gas permeable lenses ascompared to other contact lenses in 43 moderateand nine severe keratoconus eyes of 26 patientsThere has been no other comparative study tocompare the functional outcome between theRose-K lenses and the conventional RGP lenses.We found that the visual acuity was similar inboth the groups; however the comfort level inRose-K - lenses was greater as compared to theRGPlenses with acceptable fit.One of the drawbacks of our study was that wedidn’t study the functional outcome with morerecent contact lenses like the soft perm lenses,and customized lenses due to lack of availabilityand high cost.One patient with bilateral severe keratoconus,who did not have acceptable fit even with Rose-K lenses was fitted with Boston scleral lenses. Thevision improved to 6/9 in both eyes and thepatient was comfortable.We found that in India keratoconus presents atan early age as compared to the westernpopulation. Contact lenses offer a good modalityto delay the requirement for Penetratingkeratoplasty. Newer philosophies for fittingcontact lenses and newer materials can help indecreasing the contact lens intolerance which stillremains the major indication for undergoingpenetrating keratoplasty.1. Saini JS , Saroha V et al Keratoconus in Asian eyesat a tertiary eye care facility. Clin Exp Optom2004;87:97-101.2. McMonnies CW. Keratoconus fittings: Apicalclearance or apical support? Eye Contact Lens2004;30:147-55.3. Edrington TB, Barr JT, Zadnik K, Davis LJ, GundelRE, Libassi DP, et al . Standardized rigid contactlens fitting protocol for keratoconus. Optom Vis Sci1996;73:369-75.4. Lembach RG. Use of contact lenses for managementof keratoconus. Ophthalmol Clin North Am2003;16:383-94.5. Kok JH, Cheng KH. Improvement of visual acuityand corneal physiology in keratoconus by fittingaspherical, high oxygen-permeable contact lenses.Int Ophthalmol. 1991;15:263-6.6. Pullum KW, Whiting MA, Buckley RJ. Scleralcontact lenses: The expanding role. Cornea2005;24:269-77.7. Dana MR, Putz JL, Viana MA, Sugar J, McMahonTT. Contact lens failure in keratoconusmanagement. Ophthalmology 1992;99:1187-92.8. Troutman RC, Lawless MA. Penetrating keratoplastyfor keratoconus. Cornea 1987;298-305.9. Li Lim , Konard Pseudovs et al .Penetratingkeratoplasty for keratoconus: visual outcome andsuccess l Ophthalmology 2000;107:1125-31.10. Kremer I , Eagle RC , Rapuano CJ , Laibson PR .Histologic evidence of recurrent keratoconus sevenyears after keratoplasty. Am J. Ophthalmol.References1995;119:511–2 .11. Thalasselis A, Etchepareborda J . Recurrentkeratoconus 40 years after keratoplasty . OphthalmicPhysiol Opt . 2002;22:330–2 .12. de Toledo JA , de la Paz MF , Barraquer RI ,Barraquer J . Long-term progression of astigmatismafter penetrating keratoplasty for keratoconus(evidence of late recurrence). Cornea. 2003;22:317-23.13. Abelson MB , Collin HB , Gillette TE , Dohlman CH.Recurrent keratoconus after keratoplasty. Am JOphthalmol 1980;90:672–6.14. Weed KH, McGhee CN. Referral patterns, treatmentmanagement and visual outcome in keratoconus.Eye 1998;12:663-8.15. Pearson AR ,Soneji B, Sarvananthan N.Does ethnicorigin influence the incidence or severity ofkeratoconus? Eye 2000;14;625-8.16. Thalainen A. Clinical and epidemiological featuresof keratoconus. Acta Ophthalmol Suppl 1986;178:1-64.17. Zadnik K, Barr JT, Edirington TB et al . Baslinefindings in the collaborative longitudinal evaluationof keratoconus study (CLEK) study. InvestOphthalmol Vis Sci;1998;38:2537-46.18. Dada VK, Acharjee SC, Kalra KV. Behaviour of coneof keratoconus under a well fitted hard contact lensIJO;1984;32;522-4.19. Jain AK, Sukhija J. Rose-K contact lens forkeratoconus. Indian J Ophthalmol 2007;55:121-5.20. Betts AM, Mitchell GL, Zadnik K. Visualperformance and comfort with the Rose K lens forKeratoconus. Optom Vis Sci 2002;79:493-501.