refractive surgery session - All India Ophthalmological Society

452 AIOC 2009 PROCEEDINGSREFRACTIVE SURGERY SESSIONChairman: Dr. Kasu Prasad Reddy, Co-Chairman: Dr. Tejas D. ShahConvenor: Dr. Darak Ambarish Balkrishna, Moderator: Dr. Grewal S.S.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 atShankaradeve Nethralaya, Guwahati.E-mail: kasturibhattacharjee44@hotmail.comEpi-LASIK — Advanced Surface Ablation for Treatment ofModerate to High Myopia and Myopic AstigmatismDr. Kasturi Bhattacharjee, Dr. Harsha Bhattacharjee, Mr. Ranjay Chakraborty(Presenting Author: Dr. Kasturi Bhattacharjee)It has been reported that the surface ablationprocedures are less invasive in terms of cornealbiomechanics as compared to LASIK( Laser- insitu-keratomileusis) It is found that LASIK flap isassociated with biomechanical problemswherein the hinge contributes to irregularity andmay increase coma. There has been reportedpostoperative dryness with irregular healingalong with loss of stretch effect by cuttingcollagen and increase in dermatan sulphateproteoglycan, thereby weakening the tensilestrength of the cornea .Moreover the use ofmicrokeratome in LASIK may have negativeissues in the form of epithelial defect, epithelialingrowth , persistent ocular dryness, flap relatedcomplications like free cap, button hole,wrinkled flap, etc. Again the most commonlyperformed surface ablation procedure , PhotoRefractive Keratectomy ( PRK) has been reportedto induce biochemical problem in the cornealtissue leading to apoptosis with irregularcollagen formation and slower healingcharacterized by pain and early poor acuity.Moreover disruption of Bowman membrane andrelease of cytokines and inflammatorymediators initiates myofibroblast proliferation inPRK leading to development of haze andregression.EpiLASIK as described first by Pallikaris is analternative surface ablation refractive procedurecharacterized by mechanical separation of theepithelial flap. Compared to PRK, presence of anepithelial flap is found to be associated withdecrease in post-operative pain along with fasterrestoration of visual acuity. Moreover theretained flap is reported to decrease theformation of post operative healing haze.Compared to LASIK, custom wavefront surgeryare reported to have better results in epi-LASIK.Moreover the irregularity caused by the LASIKflap hinge along with other negative issues ofLASIK like the adverse biomechanical effects ofcutting collagen and the microkeratome relatedissues of LASIK flap are absent in epi-LASIK.Thus to overcome the limitations of LASIK andPRK , we have performed epi-LASIK along withintraoperative application of mitomycin C.To evaluate the clinical outcome of epi-LASIKfor the treatment of moderate to high myopia andmyopic astigmatismMaterials and MethodsA prospective , noncomparative, interventionalcase series of 270 eyes of 172 patients who hadundergone epi-LASIK along with intraoperativeapplication of 0.02% mitomycin C without flapremoval operated between June 2006 andOctober 2007. Inclusion criteria are stablerefraction of more than one year without anyocular or systemic diseases that affects cornealepithelium and patient with no previousrefractive or intraocular surgery . Exclusioncriteria are pachymetry of < 500 micron andpatients with ocular pathology having an effecton quality of vision. Patients were informedpreoperatively of surgical procedures, alter-

REFRACTIVE SURGERY SESSION453natives and consent taken. Clearance of Medicalethics Committee of the Institution taken.Surgical TechniqueThe epithelial flap has been fashioned withAmadeus II Epikeratome ( SIS Surg Ins Sys Ltd,Switzerland). This is followed by laserapplication (Wavelight 400Hz Allegretto waveEye-Q Laser) . Mitomycin C 0.02% (15 secs/ 50 µablation) are applied following laser application,chilled BSS solution has been used at start andend of surgery. Bandage Contact Lens (BCL)soaked with vancomycin has been appliedfollowing surgery. Postoperatively , all patientsreceived steroid/antibiotics eye drops four timesa day for 4 weeks along with tear substitute fourtimes a day for 8 weeks. Bandage contact lenswas removed on 4th postoperative day. Followup has been done on day1, daily till completedepithelial healing, 1week, 1month, 3 months, 6months and 12 months postoperative. Mainparameters investigated in early postoperativeperiod are Slit lamp examination for epithelialhealing ,uncorrected visual acuity (UCVA),Postoperative pain score(scale 0 to4, subjectiveassessment). Main parameters investigated afterBCL removal are Slit lamp biomicroscopy ,Manifest Refraction , Videokeratography(PENTACAM- HR) , UCVA and BCVA( Bestcorrected visual acuity) , Haze ( grade 0-4,objective assessment) and Contrast sensitivity .Paired t test has been used to comparepreoperative and postoperative values withvariables transformed using Box Coxtransformation and analysis done usingDATAPLOT soft ware.ResultsMean age was 22.5 ± 4.4 SD yrs . Meanpreoperative spherical equivalent ( SE) was – 7.75± 1.44 SD. Mean preoperative log MAR bestspectacle corrected visual acuity ( BSCVA) was -0.2 ± 2.8 SD. 16.2% had anisometropic amblyopiawith mean log MAR BSCVA of 0.42± 0.22..Meanepithelial healing time 4.44 ± 0.42 SD days . At12 months postoperative 88.7 % of operated eyeswere within ± 0.50D and 97.5% within ± 1.00 Dof targetted refraction and SE ranged from – 0.751. Katsanevaki VJ et al; Ophthalmology 2007;114(6).2. Camellin M: J cataract refract surgery 2003;19:666-70.References± 0.44SD . 48% gained more than one line ofBSCVA. 38 amblyopic patients gained BSCVA ofone line or more. After a mean of 3 month postoperativeperiod , 16% patient presented withgrade 2-3 corneal haze. This got reduced to 5.7%after 6 months with 4% eyes (p=0.0000** )withpersistent haze at 12 months and had decrease inBCVA not more than 1 line. Contrast sensitivitywas maintained in 98% with Pelli Robson chart.DiscussionEpiLASIK is an alternative surface ablationprocedure for the treatment of refractive error.The presence of the mechanically separatedviable epithelial flap acts as a barrier to cytokinesand other inflammatory mediators to anteriorstroma thereby reducing abnormal stromalwound healing. Moreover it has been found thatkeratocyte apoptosis, myofibroblasttransformation and chondroitin sulfate synthesisis much less in epiLASIK as compared to PRKcausing less stromal haze and regression.Electron microscopy study had showed that inepiLASIK flap , basal epithelial cell morphologyremains normal with prominent basal laminahaving lamina lucida and lamina densa withintercellular desmosomal connection as well ashemidesmosomal connection with basementmembrane . Thus epithelial flap repositioningdecreases the initial loss of anterior stromalkeratocytes and may explain the elimination ofearly stromal haze . In present study of epi-LASIK, 88.7% of operated eyes were within ±0.50D and 97.5% within ± 1.00 D of the targettedrefraction after 12 months of surgery .22 patients≥ one line UCVA with enhancement of BSCVAwith anisometropic amblyopia (p

456 AIOC 2009 PROCEEDINGS(higher resolution) eye piece adaptor on thespectral domain OCT. The images thus obtaineddemonstrated the cornea with clearlydemarcated flap.The measurements were taken using the onscreen calipers as per the measuring software onthe OCT. Thickness was measured at 5equidistant measurable points along the flapwhich included the central point, two pointstowards the periphery and two points in betweenthe periphery and central point. The values thusobtained were tabulated and analyzed.Analyzing flap predictability: By tabulating theflap thickness post operatively at five differentpoints along the flap, average flap thickness (Tn)was obtained for each flap in the respectivegroups.These average values were tabulated for 30 flapsand overall average thickness for 30 flaps wascalculated for both the groups, which yielded anoverall average resultant thickness of flap forfemtosecond group (TaF) and microkeratomegroup (TaM). By comparing the preset depthsetting and resultant overall average flapthickness predictability was obtained. This wasstatistically analyzed.Analyzing flap uniformity: First each flap wasanalyzed and the difference between themaximum and minimum thickness points alongthe flap was tabulated as ‘variation’ (Vn).This value for all of the 30 flaps in each groupwas tabulated and average variation wascalculated for each group. Hence averagevariation for femtosecond group (VaF) andaverage variation for microkeratome group(VaM) were obtained, compared and statisticallyanalyzed.ResultsPredictability: The femtosecond laser flaps hadan average thickness of 94 microns (TaF) withstandard deviation of 4.96 microns. (Range: 86 -102 microns).The microkeratome flaps obtainedhad an average thickness of 148 microns (TaM)with standard deviation of 11.10 microns.(Range: 127 - 169 microns).Uniformity: The femtosecond group had anaverage variation (VaF) of 9.2 ±1.27 microns. Themicrokeratome flaps had an average variation(VaM) of 23.3 ± 447 microns.DiscussionWhen comparing the preset depth setting and theresultant flap thickness, the microkeratomegroup showed a larger deviation from thedesired value. The flaps obtained were on anaverage 28 microns away from the preset valueof 120 microns with a standard deviation of 11.10microns. The femtosecond group showed asmaller deviation. Here the preset valve was 100microns and resultant average flap thickness was94 microns with a standard deviation of 4.96microns.Hence it appears that the femtosecond laseryields more predictable flaps with respect to flapthickness. This was found to be statisticallysignificant (p

REFRACTIVE SURGERY SESSION4571. Holzer MP, Rabsilber TM, Auffarth GU;Femtosecond laser-assisted corneal flap cuts:morphology, accuracy, and histopathology; InvestOphthalmol Vis Sci 2006;47:2828-31.2. Sarayba MA, Ignacio TS, Tran DB, Binder PS A; 60kHz IntraLase femtosecond laser creates a smootherReferencesLASIK stromal bed surface compared to a ZyoptixXP mechanical microkeratome in human donoreyes; J Refract Surg. 2007;23:331-7.3. Talamo JH, Meltzer J, Gardner J; Reproducibility offlap thickness with IntraLase FS and Moria LSK-1and M2 microkeratomes; J Refract Surg.2006;22:556-61.Pain Control Following Surface AblationDr. Shaun Maria Dacosta, Dr. Babu Rajendran, Dr. Gitanjali Fernandez(Presenting Author: Dr. Shaun Maria Dacosta)The resurgence of surface ablation has seen agrowing trend among refractive surgeonstowards the use of nonsteroidal antiinfammatoryagents (NSAID) for the control ofpain. Diclofenac sodium 1,2 was the first in thearmamentarium of NSAID’s followed byKetrolac tromethamine 3 , Nepafenac 4 and Bromfenac5 ophthalmic solutions. Topical anaestheticshave also been used for controlling severe painand in patients hypersensitive to pain.The effectiveness of intracameral Lignocaine (1%Lignocaine hydrochloride) 6,7 in combination withtopical anaesthesia for reducing pain duringcataract surgery has led us to believe that it, incombination with Ketorolac tromethamine, couldpossibly offer better relief of pain followingsurface ablation.The purpose of this study therefore was tocompare the efficacy of KetorolacTromethamine/Ofloxacin and combinedKetorolac Tromethamine/Ofloxacin with 1%Lignocaine hydrochloride in reducing painfollowing Photo Refractive Kerectectomy (PRK).Materials and MethodsThis prospective, comparative, randomizedinterventional study included 60 eyes of 30patients with myopia and astigmatism(sphericalequivalent ranging from -1.25 to -7.50 diopters)who underwent either PRK or Mitomycin withPRK(MPRK) using the Allegretto WavelTMversion 1007(WaveLight Laser Technologie AG,Germany). 50µ 6.5mm PTK was done to removethe epithelium. Bandage contact lenses wereinserted at the end of the procedure to reducediscomfort. Prior to surface ablation, thepostoperative drug regimen and 5 – pointnumeric scale of pain (Table-1) were explainedand informed consent was obtained from thepatients.Table-1: 5-point numeric scale of painScorePain0 No pain1 Minimal pain2 Mild pain3 Moderate pain4 Severe painTable-2: 5-point numeric scale of pain(Mean ± SD)Time Group 1 Group 2(Mean ± SD) (Mean ± SD) P value2 hrs 1.15 ± 1.03 0.89 ± 1.01 0.234 hrs 1.26 ± 1.16 1.04 ± 0.98 0.246 hrs 1.19 ± 1.14 1.22 ± 1.01 0.848 hrs 1.56 ± 1.25 1.52 ± 1.28 0.8424 hrs 1.04 ± 1.13 0.89 ± 1.01 0.3448 hrs 0.93 ± 0.99 0.89 ± 0.97 0.81Patients were randomized to receive TopicalKetorolac Tromethamine/Ofloxacin in one eye(Group-1) and combined KetorolacTromethamine/Ofloxacin with 1% Lignocainehydrochloride in the other eye (Group-2)following surface ablation. Under sterileconditions, one vial of intracameral 1%Lignocaine hydrochloride was withdrawn andmixed with Topical KetorolacTromethamine/Ofloxacin for Group 2. The eyedrops were labeled for each eye and the patientswere advised to use the drops four times a day

458 AIOC 2009 PROCEEDINGSin each eye for four days, taking care not tointerchange the marked bottles. A5 – pointnumeric scale of pain was used to rate pain at 2,4, 6, 8, 24 and 48 hrs following the treatment.Patients were reviewed on the fourth postoperative day, contact lenses were removed, anyallergic reaction to the eye drops were looked for,epithelial healing was assessed, visual acuitynoted and the pain score card was collected.Statistical AnalysisMedCalc statistical software version 9.3.0.0 wasused for statistical analysis.ResultsThis prospective, comparative, randomizedinterventional study comprised of 11 males and19 females. The mean age was 29.80 ± 8.99 years.44 eyes underwent PRK (-1.25 to -5.75diopters)and 16 eyes underwent MPRK (-6.0 to -7.5diopters). Of the 30 patients, only 1 patientdeveloped swelling of the lids and redness whichwas attributed to allergy to Ketrolactromethamine/Ofloxacin. Epithelial healing linewas visible in the majority of eyes on the fourthpostoperative day.Group 2 experienced less pain than Group1.Although both groups experienced maximumpain at 8 hrs (Table 2), there was no statisticallysignificant difference between them (p=0.84).Both groups also showed gradual decrease inpain at 24hrs (p=0.34) and 48 hrs (p=0.81).DiscussionPhotorefractive keratectomy can producesignificant ocular pain. Though post operativepain after PRK has reduced following the use ofthe newer low fluence machines, many differentdrugs and methods are being used to reduce this.Several studies 4,5,8 have reported on the safety andeffectiveness of NSAID’s in controlling painfollowing PRK.This is the first study to combine 1% Lignocainewith Ketorolac Tromethamine/ Ofloxacin andcompare it with KetorolacTromethamine/Ofloxacin in controlling painafter PRK. In this study, we found no significantdifference in the pain scores, when Ketorolactromethamine/Ofloxacin(Group 1) wascompared with combined 1%Lignocaine/Ketorolac tromethamine/Ofloxacin(Group 2). Maximum pain was felt at 8hrs in bothgroups, though it was clinically and statisticallynot significant. A tendency for gradual reductionin pain was observed on the first and secondpostoperative days in both groups.In conclusion, this study has shown that bothKetorolacTromethamine/Ofloxacin andcombined Ketorolac Tromethamine/Ofloxacinwith 1% Lignocaine hydrochloride are effectivein reducing pain following PRK.References1. Weinstock VM, Weinstock DJ, Weinstock SJ.Diclofenac and Ketorolac in the treatment of painafter photorefractive keratectomy. J Refract Surg.1996;12:792-4.2. Franqouli A, Shah S, Chatterjee A, Morgan PB,Kinsev J,.Efficacy of topical non steroidal drops aspain relief after excimer laser photorefractivekeratectomy. J Refract Surg. 1998;14:S207-8.3. Narvaez J, Krall P, Tooma TS. Prospective,randomized trial of diclofenac and Ketorolac afterrefractive surgery. J Refract Surg. 2004;20:76-8.4. Donnenfeld ED, Holland EJ, Durrie DS, RaizmanMB. Double masked study of the effects ofnepafenac 0.1% and ketorolac 0.4% on cornealepithelial wound healing and pain after PRK. AdvTher. 2007;24:852-62.5. Durrie DS, Kernard MG, Boqhossian AJ. Effects ofnonsteroidal ophthalmic drops on epithelial healingand pain in patients undergoing bilateralphotorefractive keratectomy(PRK). Adv.Ther.2007;24:1278-85.6. Gillow T, Scotcher SM, Deutsch J et al. Efficacy ofsupplementary intracameral lidocaine in routinephacoemulsification under topical anaesthesia.Ophthalmology 1999;106:2173-7.7. Boulton JE, Lopatatzidis A, Luck J, Baer RM. Arandomized controlled trial on intracamerallidocaine during phacoemulsification under topicalanaesthesia. Ophthalmology 2000;107:68-71.8. Caldwell M, Reilly C. Effects of topical nepafenacon corneal epithelial healing time and postoperative pain after PRK: a bilateral, prospective,randomized masked trial. J Refract Surg.2008;24:377-82.

REFRACTIVE SURGERY SESSION459The Role of Ultrasound Biomicroscopy in Assessing ImplantableCollamer Lens SizingDr. Mathew Kurian, Dr. Hemamalini, Dr. Rohit Shetty, Dr. K. Bhujang Shetty(Presenting Author: Dr. Hemamalini)The posterior chamber phakic implantablecollamer lens (ICL) developed by StaarSurgical AG is a monoblock single piece flat platehaptic made of collamer.It is designed to be implanted in the posteriorchamber, behind the iris and in front of theanterior capsule of the lens, with the hapticsresting in the ciliary sulcus. Since the ICL isplaced in the sulcus it requires accurateintraocular sizing calculations. To measuresulcus size most surgeons measure limbus size(white to white diameter) as measured onOrbscan II. The length of the calculated phakicIOL is then adjusted by adding 0.5 mm formyopic eyes or by subtracting 0.5mm forhyperopic eyesUBM is an ideal tool for visualizing structuresthat are difficult to study in living eyes. Itsresolution and ability to produce images of theposterior chamber and the sulcus provide aunique qualitative method for testing the exactposterior chamber phakic intraocular lenslocation and its relationship with the adjacentintraocular structures, including the lens, ciliarybody, zonules, and iris.In addition ultrasound biomicroscopy providesquantitative data like reproducible preoperativeanterior chamber and sulcus to sulcusmeasurements and postoperatively can be usedto measure distances between the posteriorchamber phakic intraocular lenses and thesestructures.To study the role of UBM in determining the sizeof ICL. To analyse position of ICL postoperativelywith respect to adjacent intraocularstructures and to measure parameters withrespect to ICL and other structures.Materials and MethodsThis was a prospective study for which IERBclearance and informed consent was obtained.All cases which underwent ImplantableCollamer Lens (ICL) implantations from March2007 to March 2008 were included.All surgeries were performed by a singlesurgeon.Standardized UBM scans were done by a singleexaminer both pre-operatively and postoperatively.Patient SelectionInclusion Criteria(1) Age > 23 years, (2) UCVA 6/60, (4) Stable myopia, (5) Normalanterior segment, (6) Endothelial count >2300cells/mm2, (7) IOP 2.9mm., (9) Normal peripheral retina andtreatment with photocoagulation if necessary.Exclusion Criteria(1) Presence of cataract, (2) Corneal pathology,(3) Narrow angle glaucoma, (4) Intraocularinflammation, (5) Diabetes, infections or retinalproblems.ICL Calculation• ICL power calculation(1) Refraction (manifest/cycloplegic), (2)Keratometry, (3) Desired target post-operativerefraction, (4) Corneal thickness, (5) ACD.• ICL sizing— Horizontal white to white (Orbscan)— Horizontal sulcus diameter (UBM).Post-Operative Follow UpPatients were reviewed on day 1 and 7, 6 weeksAll patients underwent a thorough ocularexamination with Correction of residualrefractive error if any.Assessment of Vault:UBM was done for measuring the ICL vault andthe distance of the ICL from the cornealendothelium.ResultsPatients in the study included those undergoingspherical implantable collamer lens implantationas well as those undergoing toric implantable

460 AIOC 2009 PROCEEDINGScollamer lens implantation, the first groupconsisting of 61 eyes and the TICL groupconsisting of 31 eyes.Post-Operative UBM MeasurementsHIGH VAULT: There were 4 cases (5.56%) ofvault greater than 1.00 mm, only 3 of which weredetected as high vault on slit lamp examination.The mean vault in these patients was 1.33 mm ±0.22.BORDERLINE VAULT: In 12 of 72 eyes (16.67%)the vault was greater than 0.75 mm but less than1.00 mm. The mean vault in these cases was 0.84mm ± 0.07. Only one of these was detected ashigh vault on slit lamp evaluation.NORMAL VAULT: Forty eyes (55.56%) had avault between 0.50 mm and 0.74 mm. The meanvault was 0.63 mm ± 0.07. 16 eyes (22.22%) had avault between 0.49 mm and 0.25 mm. The meanvault was 0.40 mm ± 0.07.DiscussionPhakic Implantable Collamer Lenses are FDAapproved for the treatment of myopia. However,long term complications are noted with improperICL sizing. Additional information gathered bypre and post operative UBM measurements mayhelp in reducing the incidence of ICL sizing error.In this study, the Bland Altman plot showed agood agreement between the measures obtainedby the Orbscan II and the UBM. However, theestimation of the ICL size varied in more than50% of the patients and the Orbscan tended toover estimate the ICL diameter in larger eyeswhile underestimating in smaller eyes. Attemptshave been made to improve the accuracy of directmeasurement of the sulcus.The long term success of ICL implantationdepends on an accurate selection of the ICL sizedetermined before surgery that is currently doneusing the horizontal white-to- white distance andanterior chamber depth on Orbscan..Our study suggests that the UBM may be a usefultool to help in the determination of the ICLdiameter and also in the objective assessment ofthe vault in the post-operative period.Special care needs to be taken in patients wherethere is poor correlation between the white towhite according to the Orbscan and the sulcusdiameter measured by the UBM.Lasik Results in High Myopic and Mixed Astigmatim with PulzarZ1, A Solid State Refractive LaserDr. Tarak Pujara, Dr. Paul van Saarloos, Dr. Gabriel Marin(Presenting Author: Dr. Tarak Pujara)Laser Vision Correction (LVC) with Laser insitu Keratomileusis (LASIK) andPhotorefractive Keratectomy (PRK) areestablished surgical options for the correction ofametropia. Excimer lasers have been used widelyfor LVC and now an established and maturetechnology. Every technology has its ownadvantages and disadvantages. Results withExcimer Laser (193 nm) depend on tissuehydration and also warm-up time is long. Yourequire expensive and toxic Argon Fluoride (ArF)gas for the generation of 193nm wavelength, andhigh voltage and current. Solid state wasdeveloped to overcome all of the issues of gas,high voltage and dependence on hydration. Solidstate laser utilizes Nd:Yag laser as a source.Nd:Yag laser has 1064 nm and this laser beam istransmitted through three non linear crystals toconvert it in to 213 nm. This 213 nm laser is usedfor tissue ablation in refractive surgery. It hasbeen claimed that it is less dependent on tissuehydration, has less thermal effect and collateraldamage and requires much less electricity to runthe laser. It is also claimed that it produces cleanand smooth ablated surface and has moreefficient tissue ablation.This study is being performed to evaluate clinicalefficacy, predictability and safety of 213nm solidstate laser for the correction of myopia withastigmatism.Materials and MethodsPulzar Z1 (213 nm) Solid State Refractive Laser(Manufactured by CustomVis, Australia) is

REFRACTIVE SURGERY SESSION461used to treat all cases at Poblado Clinica Medellin(Colombia). All cases were operated by only onesurgeon.A retrospective study of fifty consecutive eyeswith pre operative spherical correction rangingfrom +4.75 to -7.00 diopter (D) with astigmatismranging from -3.00 D to -6.50 D. Informed consentwas obtained from all patients for performing thelaser surgery. The study and all patients weremonitored by local investigators. All patientswere at least 18 years of age with a stablerefraction over a six months period prior tosurgery. Patients in this study had naturallyoccurring myopia and astigmatism prior tosurgery.Testing was performed preoperatively and 1 day,1 month and 3 months post operatively. Testingincluded a complete ophthalmologic examination,including uncorrected visual acuity,manifest refraction, best spectacle correctedvisual acuity, pre operative pachymetry, cornealtopography and wavefront examination.Surgery was performed in a particle freeenvironment with patients under topicalanesthesia. Most of the patients underwent Laserin situ Keratomileusis (LASIK) and patientsoperated at the Norway site underwent PhotoRefractive Keratectomy (PRK). Moria CB andHansatome Microkeratomes were used in allLASIK cases.The ablation was carried out by PULZAR Z1,Solid State Refractive Laser manufactured byCustomVis, Australia. Every surgeon used theMicrokeratome of his choice. Antibiotic andsteroid eye drops were given according tosurgeon’s preference.ResultsAll fifty eyes were followed for at least thirteenweeks. All patients underwent a completeophthalmologic examination, includinguncorrected visual acuity, manifest refraction,best spectacle corrected visual acuity, postoperative pachymetry, corneal topography andwavefront examination post operatively.90% of cases had 20/30 or better UncorrectedVisual Acuity (UCVA) at an average follow up of13 weeks and 94% had UCVA 20/40 or better.On vector analysis average percentage vectorchange was 93% suggesting littleundercorrection. Error in vector angle wasaveraged 2 degrees. Post-operative patientsatisfaction was high. As some of the follow–upsare as early as 2 weeks, the chance ofimprovement in results is high.DiscussionAstigmatism corrections were predictable andeffective with the Pulzar Z1 Solid State Laser.Nomogram adjustments will provide even betteroutcomes.Results are as promising as the excimerlaser.Longer follow up and nomogram refinement areneeded, especially in high myopia and highastigmatism for excellent results. As it is a newlydeveloped system, there is huge scope fordevelopment and progress compared to theexcimer laser as it is now a matured technologywith little scope of further development.Q-Factor Adjusted Aspheric Ablation Profiles for The Correctionof Myopic Astigmatism Give Superior Results Even for Low AndModerate Myopia–A Comparative Cohort StudyDr. Anand Parthasarathy, Dr. Arvind.V, Dr. R. Rajendran, Dr. S. Lalitha,Dr. Malini B Moorthy, Dr. Premraj. K(Presenting Author: Dr. Anand Parthasarathy)Corneal refractive surgery with the use ofexcimer laser is an effective procedure forcorrection of refractive error with stable postoperative outcomes. However the prolateness ofthe cornea (where the central cornea has a lesserradius of curvature than the periphery) is alteredafter the ablation for myopic astigmatism leadingto an oblate cornea (where the peripheral corneashas a leser radius of curvature than the centralcornea). In this study we look at the results of the

462 AIOC 2009 PROCEEDINGSTable-1: Table showing the demographics andpatient characteristics for the three groupsModerate MildMyopia Myopia PlanolasikNo of Eyes 32 32 32Q values (Mean) -0.26 -0.34 -0.36Pre Op SE -5.44 D -2.26 D -6.61 DKeratometry 43.96 44.25 44.10Optical Zone 6.12 mm 6.26 mm 5.9 mmFlap Size 9.0 mm 9.0 mm 8.75 mmQ-factor adjusted aspheric ablation profiles forthe correction of myopia with the help of a cohortstudy of patients.Materials and MethodsStudy Group: Patients treated with Q-factorcustomized aspheric profile were selected andthen divided in to groups for mild and moderatemyopia were prospectively recruited.Control Group: Control group consisting ofpatients who underwent planoLASIK that werematched with the study groups within 1 diopterof the spherical equivalent.Patient examination: Preoperative and 1-monthpostoperative wavefront aberrometry,uncorrected visual acuity, best corrected visualacuity and predicted phoropter (PPR) values aswell as the corneal asphericity were comparedbetween the 3 groups. Bausch and LombTechnolas 217 excimer laser was used for lasertreatment and the Q factor analysis pre andpostoperatively was determined KQ calculatorfound on the machine. ANOVA was used forcomparison between groups; pre andpostoperative visual acuity comparisons wasdone with student’s t test, Bonferroni correctionwas used for inter group comparisons.ResultsNinety six eyes of 48 patients (16 in each group)were included in the study. The surgery wasuneventful in all cases.The mean preoperative spherical equivalents (SE)of -5.44 diopters, -2.26 D, -6.61 D for moderate,mild, control groups respectively. UCVAimproved in all patients from preoperativevalues (p0.5),keratometry values (43.96 vs 44.25 vs 44.10), flapthickness (p>0.5) or optical zone for ablation(p>0.5) as shown in Table 1. Analyzing theasphericity of the cornea by looking at the pre topost operative change in Q value ( figure 1); thechange was more for planoLASIK than for Qadjusted patients.; further for myopia upto -4 DSE, the Q-factor optimized treated eyes had asmaller shift towards an oblate cornea.DiscussionIn India plano LASIK is still the most commonlyperformed ablation and hence it was chosen asthe control group for the Q adjusted LASIKgroups. The study did demonstrate that Qadjusted LASIK can be used for mild andmoderate myopia with good refractive accuracy.There is a shift toward an oblate cornea thatlinearly correlates with the amount of myopiccorrection attempted; this is important since theincorporation of the Q factor in the laser factorinvolves an additional mid peripheral correctionthat enhances central ablation depth.Custom-Q ablation profiles showed morerefractive accuracy and are clinically superior toplanoscan profiles with less impairment ofcorneal asphericity especially for corrections upto -4D SE. More specific comparisons withrespect to the aberrations induced by the surgeryand comparison with a wavefront guided ablationwould be the focus of our follow up studies.

REFRACTIVE SURGERY SESSION463Visual Outcomes of Visian ICL and TICL ImplantationDr. Mathew Kurian, Dr. Manju S. Babu, Dr. Rohit Shetty, Dr. K. Bhujang Shetty,Dr. Hamamalini M.S.(Presenting Author: Dr. Manju S. Babu)Posterior chamber phakic intraocular lensimplantation is an option for the surgicalcorrection of high myopia and hyperopia. TheVisian implantable collamer lens, developed byStaar Surgical AG (Nidau, Switzerland), is amonoblock single-piece flat plate haptic lensmade of Collamer (an extremely hydrophilic andhighly biocompatible flexible collagen copolymerwith a refractive index of 1.452 that is permeableto oxygen and nutrients). 1 It is designed to beimplanted in the posterior chamber, behind theiris and in front of the anterior lens capsule, withan aqueous humor layer separating it from thelens and the haptics resting on the ciliary sulcus.To document the surgical outcomes followingToric and Spherical Visian Implantable Collamerlens (ICL) implantation.Materials and MethodsType of study: Prospective observational caseseries.Sources of data: All patients undergoingposterior chamber phakic intraocular lensimplantations at Narayana NethralayaInclusion Criteria: Age: 21-45 years, Ametropianot correctable with excimer laser surgery;Spherical equivalent of myopia between -9.00and -20.00 D ,BCVA of at least 6/18, Stablerefraction for one year. (+/-0.5D for 6months),IOP less than or equal to 21 mm Hg.Open anterior chamber angles (Shaffer grade 3and 4 or or Scheie grade 0 and 1),Anteriorchamber depth of greater than or equal to 2.8mm,Normal peripheral retina or treatment withphotocoagulation when necessary,No previousocular surgery.Exclusion criteria: Corneal degeneration/dystrophies,Lens opacities/developing cataract,Pseudoexfoliation, Pigmentary dispersion,Glaucoma, H/O uveitis/ intraocularinflammations, Macular pathology,Rubeosisiridis.Signed, written, informed consent was obtainedfor all the cases.Surgical Technique of ICL ImplantationUnder the microscope the ICL was loaded intothe STAAR super funnel injector cartridge usingVukich ICL forceps (ASICO,Westmont,Ilinois) orthe modified Aus der Au forceps(Janach, Como,Italy). After topical 1% proparacaine (Paracaine)eye drops were instilled to anaesthetize the eye,the patient was draped and a lid speculuminserted. Three minutes before the cornealincision, povidone iodine 5% was administeredto the ocular surface. Paracentesis were made at12 and 6 O’clock positions and hydroxy-propylmethyl-cellulosewas injected into the anteriorchamber. A 2.8 mm temporal clear cornealincision was made and viscoelastic readministeredinto the anterior chamber. The tipof the injector cartridge was then inserted into thetemporal corneal wound, the ICL was deliveredinto the anterior chamber, and the haptics wereplaced behind the iris with a manipulationforceps (Duckworth and Kent, Baldock,Hertfordshire, England). When a toric ICL wasimplanted it was rotated according to theimplantation software (i.e., clockwise or counterclockwise).2 A surgical peripheral iridectomywas performed using the vitreous cutter at 12O’clock after constricting the pupil withintracameral pilocarpine. The viscoelastic wasaspirated out using irrigation-aspiration and thewounds were hydrated after reforming theanterior chamber.ResultsSpherical Implantable Collamer LensPatient PopulationThis group consisted of 61 eyes of 41 patients ofwhich 31 were right eyes and 30 were left eyes.24 were male and 17 were female patients. Themean pre-operative age was 26.2 ± 5.96years.Pre-Operative Refraction DataThe mean UCVA was 0.03 ± 0.02 and the BSCVA(best spectacle corrected visual acuity) was 0.65± 0.28 in the decimal system. The mean spherewas -15.36 ± 3.39 dioptres and the mean cylinder

464 AIOC 2009 PROCEEDINGSwas -1.25 D ± 0.77. The mean refractive sphericalequivalent (MRSE) was -15.92 ± 4.01 dioptres.The average Keratometry value was 44.20D.Post-Operative Refraction DataThe mean ICL power implanted was -19.73 D +3.25, mean size was12.14 mm ± 0.32 and thepredicted refraction was -0.41 + 0.71. Thepostoperative mean UCVA was 0.63 + 0.83 andthe mean BSCVA was 0.70 + 0.27. The mean postoperativesphere was -0.8D + 1.05, the meancylinder was -0.72D ± 0.56 and the achievedMRSE was -0.92 D + 1.12. Pre-operatively nearly75% were more than -14D and that postoperativelymore than 80% were within 2Dioptres of plano. The uncorrected Snellen’sacuity in 98% of patients with ICL implantationswas 6/18. Further 83% of patients exceeded theirpre-operative BCVA at the 6/12 level.Toric Implantable Collamer LensPatient PopulationThis group consisted of thirty-one eyes of twentytwo patients of which 19 were right eyes and 12were left eyes. 6 were male and 16 were femalepatients. The mean pre-operative age was 25.13± 5.85 years.Pre-Operative Refraction DataThe mean UCVA was 0.03 ± 0.04 and the BSCVA(best spectacle corrected visual acuity) was 0.68± 0.27according to the decimal system. The meansphere was -11.37 D ± 4.5 and the mean cylinderwas -2.96 ± 1.22 dioptres. The mean refractivespherical equivalent (MRSE) was -12.85 ± 4.37dioptres.The mean flat K was 43.9 D ± 2.05, the steep Kwas 46.25 D ± 2.10 and the average Keratometryvalue was 45.08 D ± 2.02.Post-Operative Refraction DataThe mean Toric ICL power implanted was -18.53Dioptre Sphere + 4.55, + 3.43 Dioptre Cylinder ±1.70, the mean size was 12.10 mm ± 0.37 and thepredicted refraction was -0.15 + 0.76. The meanUCVA was 0.51 ± 0.21 and the mean BSCVA was0.76 ± 0.20. The mean post operative sphere was-0.26D ± 1.03, the mean cylinder was -0.96D ± 0.80and the mean refractive spherical equivalent was-0.74 ± 1.10 dioptres. Pre-operatively more than40% were more than -14D and nearly another40% were between -10 to -14 D. Post-operativelymore than 90% were within 2 Dioptres of plano.The uncorrected Snellen’s acuity in all 100% ofpatients with TICL implantations was at least6/18. 94% of patients exceeded their preoperativeBCVA at the 6/12 level.Both the Toric and spherical ICLs were safe andefficacious in giving good refractive results in ourseries.References1. Feijoo J’n G, Alfaro I.J, Me´ndez-Hernandez C, et al.Ultrasound Biomicroscopy Examination ofPosterior Chamber Phakic Intraocular LensPosition: Ophthalmology 2003;110:163–17.2. 2.Sanders D.R,Schneider D, Vukich J, et al .ToricImplantableCollamer Lens for Moderate to HighMyopic Astigmatism: Ophthalmology2007;114:54–61.3. Alio, J. L. Advances in phakic intraocular lenses:indications, efficacy, safety, and new designs:Current Opinion In Ophthalmology 2004;15:350-7.4. Koivula A, Petrelius A, Zetterstro¨m C. Clinicaloutcomes of phakic refractive lens in myopic andhyperopic eyes : 1-year results: J Cataract RefractSurg 2005;31:1145–52.5. Silva, Ruwan A, Jain A, Edward E, et al. ProspectiveLong-term Evaluation of the Efficacy, Safety, andStability of the Phakic Intraocular Lens for HighMyopia:Archives of Ophthalmology 2008;126:775-81.