cataract session - All India Ophthalmological Society

CATARACT SESSION - I59AUTHOR'S PROFILE:DR. ABHAYKUMAR R. VASAVADA: M.S. (’75) University, Baroda; F.R.C.S. (Eng.) (’80).Recipient of (i) B.C. Roy Award, (ii) Asia Pacific Association of Cataract and RefractiveSurgeons Educator Award (2002). Published 135 publications in peer reviewed journals.Presently, (i) Director (Medical) and Phacosurgeon Raghudeep Eye Clinic, (ii) Director(Research), Iladevi Cataract and IOL Research Centre, of Gurukul, Memnagar, Ahmedabad,Gujarat.Contact: (079) 27490909; E-mail: icirc@abhayvasavada.comThe use of a topical antibiotic agent combinedwith povidone–iodine immediately beforesurgery is the most frequently practiced methodto reduce the flora on the conjunctival surface.The optimum preoperative antibiotic regimenhas not been defined. It has been hypothesizedthat administering a topical antibiotic agent onthe same day as surgery does not allow adequateexposure time to reduce the bacterial count and,therefore, that a regimen in which the agent isapplied beginning the day before surgery is moreeffective. 2 Some ophthalmologists recommendusing a topical antibiotic agent for several daysbefore surgery, whereas others believe that theuse of antibiotic agent on the day of surgery isadequate. Others use a combination of thesemethods. We hypothesized that being aconcentration dependent drug, moxifloxacinwould be equally effective if the dosing began onthe day of surgery. The study presented heresought to determine whether the 2 regimenswere also effective in reducing conjunctivalbacterial flora in patients having cataract surgery.Materials and MethodsThis prospective randomized study comprised148 patients having phacoemulsification atIladevi Cataract and IOL Research Centre fromDecember 2006 to December 2007.CATARACT-IChairman: Dr. Gautam Bhaduri, Co-Chairman: Dr. Kapil VohraConvenor: V. Sambasiva Rao, Moderator: Dr. Lalit Kumar NepaliaResidual Conjuctival Flora Following 2 Regimens of VigamoxDuring Pre-Operative Prophylaxis: A Prospective RandomizedTriple Masked TrialDr. Abhay R. Vasavada, Dr. Nirmit V. Dixit, Dr. Shetal M. Raj, Dr. Devarshi Gajjar,Dr. Vaishali Vasavada, Dr. Viraj Vasavada(Presenting Author: Dr. Nirmit V. Dixit)Patients older than 55 years who had uninflamedeyes and normal corneal epithelium wererecruited. Patients who refused to give consentor had 1 functional eye were excluded. Otherexclusion criteria included associated ocularanomalies, sensitivity to quinolones, anincorrectly administered regimen, use of topicalmedications 2 weeks before entry into the study,untreated meibomianitis, and blepharitis.Sample CollectionTwo days before surgery, an assistant wasinstructed to confirm that no concomitant topicaltreatment was administered before the swabswere collected. Swabs were taken withoutanesthesia by inserting the moist swab in thelower conjunctival fornix at the nasal margin androtating it along the fornix to the temporalmargin. The same swab was then rotated alongthe margins of the upper and lower eyelids. Next,patients were randomly assigned to 1 of 2 groupsbased on prophylactic regimen of Vigamoxinstillation. Patient assignment was based oncomputer-generated randomization. In Group 1,patients were instructed to instill Vigamox 4times beginning 1 day before surgery plus 1 drop2 hours before surgery (total of 5 drops beforesurgery). In Group 2, patients were instructed toinstill Vigamox 2 hours before surgery and thenevery 15 minutes for the second hour (total of 5

60 AIOC 2009 PROCEEDINGSdrops before surgery; no dosage the day before).Each patient was given the respective printedregimen to ensure proper instillation of theVigamox. Patients marked the exact time ofdosing on a separate sheet. In addition to theantibiotic regimens, all patients received topicaltropicamide 1% eyedrops (Tropicamet) twice 30minutes apart 1 hour before surgery.To reduce operator sampling bias, the sametechnician, who was masked to therandomization, collected all swabs using astandardized technique. After Vigamoxinstillation and before povidone–iodineinstillation, conjunctival and eyelid swabs werecollected. After povidone–iodine was applied,phacoemulsification was performed. Aftersurgery, the swabs were inoculated into a bijoubottle containing 2 mL tryptone soya broth with0.5% sodium thiosulphate broth and transferreddirectly for culture within 3 hours of being taken.To reduce bias, the swabber/irrigator andmicrobiologist were blind to the antibioticregimen. The code matching the patient with theantibiotic regimen was not broken until all themicrobiological data were complete.Quantitative AnalysisIn the microbiology laboratory, the samples werevortexed for 30 seconds. Subsequently, 3 aliquotsof 100 µL were collected and each aliquot wasspread onto (1) a chocolate blood agar plate andincubated for 48 hours in 10% carbon dioxide; (2)an anaerobic basal agar containing 5% horseblood and incubated for 48 hours in 10% carbondioxide; (3) nutrient agar and incubated for 48hours (aerobically). Bacterial growth wasevaluated in a quantitative manner as CFU.Colonies were counted manually using anilluminated colony counter with a grid format.The average CFU at each measurement wascalculated from the 3 plates and converted intothe number of bacteria per 2 mL of tryptone soyabroth (equal to number of bacteria per eye) usingthe following equation: Total number of CFU pereye = CFU on plate per amount of solution plated× volume of original solution.The main outcome measure was the meanpercentage reduction in CFU after instillationcalculated as follows: CFU after instillation −CFU before instillation/CFU before instillation ×100.Qualitative AnalysisBacterial species were identified usingconventional biochemical and biophysicalreactions and PIBWin software for probabilisticidentification. To further confirm the bacterialspecies, representative samples of each specieswere analyzed based on nucleotide homologyand phylogenetic analysis of the microbe bysequencing the 1.5 kb 16S r DNA fragment.ResultsOf the 148 patients recruited for the study, 3 (2 inGroup 1; 1 in Group 2) were excluded fromanalysis because of improper Vigamoxinstillation. The results of cultures taken beforeand after Vigamox instillation were available foranalysis for 145 patients (72 Group 1; 73 Group2). The mean age of the 86 men and 59 womenwas 74 years ± 10.4 (D) (range 55 to 85 years).There was no statistically significant differencebetween the 2 groups in age or sex (P = .7 and P= 1.0, respectively; unpaired t test).No patient had an adverse reaction to theantibiotic agent or swabbing procedure. No eyedeveloped postoperative endophthalmitis up tothe last recorded follow-up at 6 months.Quantitative DataBefore Vigamox instillation, 5.3% of eyes weresterile in Group 1 and 2.6% in Group 2. Afterinstillation, 9.3% and 10.6%, respectively, weresterile. Before Vigamox instillation, the meannumber of initial colonies was 1412.83 ± 643.18CFU in Group 1 and 1832.04 ± 769.27 CFU inGroup 2. There was no statistically significantdifference between the 2 groups. Table 1 showsthe change in log colony counts from beforeinstillation to after instillation in both groups.Within each group, the change in colony countsfrom before to after instillation was statisticallysignificant. The percentage reduction in colonycounts was similar between groups (P =09)(Table 1).This suggests that the antibiotic dosage in Group2 was more effective than in Group 1 in terms ofhigh initial levels of CFU.Qualitative DataThere was no statistically significant differencebetween the 2 groups in the number of isolates ofeach of bacteria after Vigamox instillation.

CATARACT SESSION - I61Table-1: Comparison of the reduction in CFU after instillation of two prophylactic regimes of vigamox.CFU (Pre- CFU (Post- % Reduction Compare % P Value of %treatment) Treatment) of CFU Reduction in Reduction inMedian (pre Median (preversus post) versus post)Group 1 Mean 1412.83 90.72 93.12SD 643.18 72.61 6.56Median 1284.00 65.00 94.48 94.94 < 0.001Minimum 331.00 10.00 49.70Maximum 4180.00 330.00 99.38Group 2 Mean 1832.04 102.43 93.28SD 769.27 81.23 8.23Median 1634.00 75.00 95.40 95.41 < 0.001Minimum 642.00 5.00 54.83Maximum 3945.00 290.00 99.61P value (P = 0.09)Of the Staphylococcus species isolated, 71% wereS epidermidis; other species include S hyicus, Shaemolyticus, S captis, S saprophyticus, Svarians, S aureus, S xylosus, S warneri.Corynebacterium pseudogenitalium was theonly Corynebacterium species isolated.Micrococcus species included M leuteus and Mvarians. Bacillus species included B subtilis andB velezensis. Gram-negative organisms includedPseudomonas aeruginosa, Pseudomonasstutzeri, Enterobacter cloacae, Enterobacterhormaechei, Proteus vulgari, and Acinetobacterspecies. The anaerobic cultures mainly consistedof Propionibacterium acnes andPeptostreptococcus species. Streptococcusspecies was present in 2% of all specimens.DiscussionSeveral studies report the presence of bacteria innormal conjunctival flora without the use ofantibiotic agents. The amount of bacteriadepends on the swabbing technique andprocessing of samples using different culturemedia. To maximize the chances for increasedbacterial recovery, we used a swabbing techniquedesigned to collect the maximum number ofbacteria on the conjunctiva and eyelids. In thetechnique, swabs before and after instillation ofantibiotic agent are obtained without topicalanesthesia to optimize bacterial growth byavoiding preservative-induced inhibition ofbacterial growth. Studies have found that whenswabs are taken from both conjunctiva andeyelids, the CFU before antibiotic instillation ishigh. In contrast, swabs taken from theconjunctiva flora before instillation have a lowCFU. In the present study, the CFU beforeantibiotic instillation was higher than that in theabove studies, mainly because the swab wastaken from the conjunctiva as well as the eyelidmargins. We did this because it has beendocumented that the eyelids are the major sourceof bacteria. It has been suggested that withsuitable culture methods, less than 5% ofconjunctival specimens remain negative. Thiscorroborates with our finding that 4% eyes weresterile before antibiotic instillation.The significant reduction in CFU after Vigamoxinstillation with both regimens suggests thesensitivity of the normal bacterial flora tomoxifloxacin. This supports in vitro findings thatmoxifloxacin possesses broad-spectrum activityagainst a wide variety of gram-positive andgram-negative organisms. There was no addedadvantage of beginning moxifloxacin on the daybefore surgery versus on the day of surgery interms of the efficacy of killing normal flora.To our knowledge, there is no peer-reviewedrandomized controlled prospective study ofmoxifloxacin showing that administering dropson the day of surgery is better or worse thanadministering them 1 day before surgery. Ta etal. showed that the previous-generationfluoroquinolone ofloxacin was more effective inkilling normal bacterial flora when administered3 days before surgery than when 1 drop was

62 AIOC 2009 PROCEEDINGSapplied 1 hour before surgery. The highfrequency of S epidermidis isolated from theocular swabs in the present study confirms thedata in several studies. Although both regimens(day of and 1 day before surgery) reduced thenumber of colonies significantly after Vigamoxinstillation,neither eradicated them from theocular surface entirely. The presence ofStaphylococcus species, although trivial, wasdetected on the swabs collected after instillation,probably because we used a very sensitivemethod for detection. It has been shown that thebacterial pattern on the conjunctiva can beinfluenced by geographic and climate factors andthat the prevalence of bacteria differs even withinthe same country.In conclusion, both regimens of topicalmoxifloxacin were effective in reducing theconjunctival and eyelid flora when used forpreoperative prophylaxis in intraocular anteriorsegment surgery. The results suggest that early,frequent administration of moxifloxacin 0.5% forpreoperative prophylaxis is not required tomaximize its beneficial effects.Visual Performance of A Foldable Diffractive Multifocal IOL withProlate Optics and A Foldable Monofocal IOL with Prolate Optics— A Comparative StudyDr. Shilpa Taneja, Dr. A.K. Grover, Dr. Shaloo Bageja(Presenting Author: Dr. Shilpa Taneja)Areduction in contrast sensitivity withmultifocal IOL’s has been extensivelyreported. 1,2,3 Inherent limitations of the diffractivemultifocal IOL’s constitute a limiting factor to itsuse. 2,3,4,5,6 Wavefront guided prolate anterior opticin monofocal lenses has been reported toneutralize the positive spherical aberration of thehuman cornea and improve contrast. 7 This studywas designed to study the contrast functionwhen a diffractive multifocal lens is combinedwith a prolate optics {Tecnis ZM900 (AdvancedMedical Optics, Inc., Santa Ana, DA)} in Indianeyes where pupil size is smaller than that in theCaucasians.Materials and MethodsThis prospective interventional study wasconducted in 45 eyes undergoingphacoemulsification between 1st November 2005and 1st November 2007. Tecnis multifocal(Group I), Tecnis monofocal (Group II) andconventional monofocal (Clariflex) (Group III)IOLs were implanted in 15 eyes each.Patients with ocular pathology other thancataract, keratometric cylinder greater than 1.0D,pupil size less than 2.5mm, those requiring IOLpower outside 15-26D, and those with high postoperativevisual acuity expectations oroccupational requirements were excluded fromenrollment. Also excluded were patients with anintra-operative complication, which hindersproper IOL centration. All cataracts wereextracted by the standard phacoemulsificationtechnique using a clear corneal 3- 3.2mmtemporal incision under topical anesthesia. Onemonth postoperatively, unaided visual acuity,best-corrected visual acuity (BCVA) for distanceand near, photopic optotype (Pelli-Robson)contrast sensitivity, sine-wave (F.A.C.T) contrastsensitivity (CS) and subjective scores (using a selfmade questionnaire) were compared between thegroups.The data was statistically analysed using nonparametricKruskal-Wallis test for comparisonbetween all 3 groups, non-parametric Mann-Whitney U test for comparison between any 2groups, non-parametric Wilcoxon Signed Ranktest for intra group analysis and Chi- square testfor the qualitative analysis.For the statisticalcalculations the SPSS for Windows statisticalpackage with a general significance set at p value

CATARACT SESSION - I63Contrast sensitivityPhotopic Optotype contrast sensitivity (PelliRobson) was higher in Group II (prolatemonofocal) as compared to Group I (prolatemultifocal). The difference was significant on day14 (p=0.017) and day 31 (p=0.043).Photopic sine wave grating contrast sensitivityfor near was higher in Group II than Group I, thedifference being statistically significant at 3cpd(p=0.001) and 6cpd (p=.001).Photopic sine wave grating contrast sensitivityfor distance was higher in Group II than Group I,the difference being statistically significant at3cpd (p=0.002), 6cpd (p=0.002) and 18cpd(p=0.023).Subjective scoresThe mean total satisfaction score without glasseswas 35.33 +/- 3.06 in group I and 22.67 +/- 4.19 ingroup II. {Out of maximum score of 40 (4 x 10questions)}Group I patients had a higher satisfaction scoresthan group II for near and intermediate workwithout glasses. (p value = 0.000)For distance work both groups had a meansatisfaction score between 3.0-3.5 implying littledifficulty in distance work. (p value = 0.486)Group I patients experienced significant amountof glare and halos (p-values=0.014) as comparedto the group II patients (p value= 0.305 i.e. nonsignificant).Our study found that 80% of the patients ingroup I and 13.3% in group II perceivedmoderate to severe (score 2,1 or 0) glare and haloswhen specifically asked for. Only one patient(7%) in group I complained of disturbing photicphenomenon on his own.DiscussionIn the present study the Tecnis multifocal IOLproduced functionally lower contrast sensitivitymeasurements than the Tecnis monofocal IOLboth by optotype and sine-wave grating tests.This decrement suggests decreased functionalvision under photopic conditions with multifocalIOL.The mean photopic contrast sensitivity (PelliRobson test) is lower with multifocal IOL group.Similar results were observed by Steinert et al 6 ,Hienrich Bleckman et al 4 , Gimble et al 8 , Kamleshet al 9 , Mercedes Vaquero et al 5 who reported areduction in contrast sensitivity with a parallelreduction in quality of vision after implantationof multifocal IOL’s.The mean photopic log C.S. (F.A.C.T.) for nearwith the multifocal IOL was lower than withmonofocal IOL at lower spatial frequencies (3cpdand 6 cpd). Our finding is in contrast to studies,which have shown the difference to be at higherspatial frequencies (12cpd and 18 cpd). 6,10,11,12 Thedistance contrast sensitivity under photopicconditions (F.A.C.T.) was also reduced withmultifocal IOL at 3, 6 and 18 cpd. Similarreduction has been reported previously. 6,10,11,12Montes Mico R et al 12 have reported that there isno significant differences between the photopicnear CS values for the multifocal and monofocalgroups but when the luminance was decreased(mesopic conditions), the near contrast sensitivitywas significantly worse than in the nearcorrectedmonofocal group at high spatialfrequencies (12 and 18 cpd) only.Our observations suggest that although PelliRobson optotype testing remains a quick methodfor contrast sensitivity measurement, F.A.C.T.sine wave grating is possibly more sensitive thanPelli Robson as F.A.C.T. can evaluate contrastsensitivity function at various spatial frequencies.Many patients who had exactly the samenumerical value of log contrast sensitivity withPelli Robson method showed absolutely differentcurves with F.A.C.T. method.The patients implanted with multifocal IOL withmodified anterior prolate optics were generallyextremely satisfied with their visual results assuggested by our subjective scores. Patients whoreceived multifocal IOLs at time of surgeryobtained better uncorrected and distancecorrected near VA and reported better overallvision, less limitation in visual function and lessspectacle dependency. 13,14A relatively short follow up period, a smallsample size and study confined to photopiccontrast sensitivity are the shortcomings of thisstudy. A study with larger groups of patients andwith other variables may be needed to gathermore information.

64 AIOC 2009 PROCEEDINGSReferences1. Duffery R, Zabel R, Lindstrom R .MultifocalIntraocular Lenses. J Cataract Refract Surg. 1990;16:423-9.2. Holladay J, Van Dijk H,Lang A. Opticalperformance of multifocal intraocular lenses. JCataract Refract Surg. 1990;16:413-22.3. Rosseti L,Carraro R, Rovati M. Performance ofdiffractive multifocal intraocular lenses inextracapsular cataract surgery. J Cataract RefractSurg. 1994;20:124-8.4. Bleckman H,Schmidt O,Sunde T,Kaluzny J.Visualresults of progressive multifocal posterior chamberintraocular implant. J Cataract Refract Surg.1996;22:1102-7.5. Vaquero-Ruano M, Encinas JL, Millan I,Hyos M,Cajigal C.AMO ARRAY multifocal vs. monofocalIOL’s – Long term follow up. J Cataract Refract Surg.1998;24:118-23.6. Steinert RF,Post CT,Brint SF,et al .A prospectiverandomized double-masked comparison of a zonalprogressive multifocal IOL. Ophthalmology1992;99:853-61.7. Artal P, Berrio E, Guirao A, Piers P. Contributionof the cornea and internal surfaces to the change ofocular aberration with age. J Opt. Soc Am A2002;19:137-43.8. Gimbel HV, Sanders DR, Raanan MG. Visual andrefractive results of multifocal intraocular lenses.Opthalmology 1991;98:881-8.9. Kamlesh Dadeya S, Kaushik S. Contrast sensitivityand depth of focus with aspheric multifocal versusconventional monofocal intraocular lens. Can JOpthalmol 2001;36:197-201.10. Vingolo EM, Grenga P, Iacobelli L, Grenga R.Visualacuity and contrast sensitivity: AcrySof ReSTORapodized diffractive versus AcrySof SA60ATmonofocal intraocular lenses. J Cataract Refract Surg.2007;33:1244-7.11. Chiam PJ, Chan JH, Aggarwal RK, Kasaby S.ReSTOR intraocular lens implantation in cataractsurgery: quality of vision. J Cataract Refract Surg.2006;32:1459-63.12. Montés-Micó R, España E, Bueno I, Charman WN,Menezo JL. Visual performance with multifocalintraocular lenses: mesopic contrast sensitivityunder distance and near conditions, Ophthalmology2004;111:85-96.13. Javitt JC, Steinert RF.Cataract extraction withmultifocal intraocular lens implantation: amultinational clinical trial evaluating clinical,functional, and quality-of-life outcomes.Ophthalmology 2000;107:2040-814. Stallet G.Refractive outcome after bilateralimplantation of an apodized diffractive intraocularlens. Bull. Soc. Belge Ophtalmol. 2006;299:67-73.Use of A Mydriatic Cocktail with A Wick for PreoperativeMydriasis in Cataract Surgery-A Prospective RandomizedControlled TrialDr. Sabyasachi Sengupta, Dr. Renuka Srinivasan, Dr. Vanuli Agarwal,Dr. Datta G. Pandian(Presenting Author: Dr. Renuka Srinivasan)Pupillary dilation is an integral component ofpreoperative preparation for cataract surgery.This has traditionally been accomplished bytopical instillation of mydriatic drops like 2%homatropine, 1% cyclopentolate and 1%tropicamide eye drops with or without 2.5%phenylephrine eye drops. Other forms of drugdelivery to effect pupillary dilation includeointment delivery such as atropine eye ointment,intra cameral mydriatic 1 and mydrisert 2 , asustained release formulation. A sub conjunctivalinjection of mydricaine which consists of equalproportions of adrenaline, atropine andlignocaine is also efficacious in dilation ofpatients with poor mydriasis. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) likeflurbiprofen or diclofenac are also used alongwith the dilating regimen as they maintain theintra operative mydriasis. 5-8 It is imperative tohave adequate and sustained mydriasis andoptimum corneal clarity during intraocularsurgery. However, repeated instillation ofmydriatic and anti-inflammatory ophthalmicsolutions during preoperative dilation may affectcompliance and may damage the cornealepithelium. Pupils are frequently dilated on theday before cataract surgery so as to enablefundus examination. This may, however,

CATARACT SESSION - I65interfere with mydriasis on the day of surgery,termed pupillary fatigue. 9Materials and Methods225 eyes of 225 patients were included in thisstudy carried out over a period of six months.The study included all patients enrolled forcataract surgery with grade II and III nuclearsclerosis as per the Lens OpacificationClassification System III (LOCS III). Patientsexpected to have poor mydriasis like diabeticsand those with pseudoexfoliation (PXF) werealso included in the study. Patients with posteriorsynechiae due to long standing uveitis,glaucoma, those with corneal pathologies,phacotoxic uveitis etc were excluded from thisstudy. Individuals with systemic hypertensionand ischemic heart disease were also excludedowing to use of phenylephrine in the cocktailregimen. All patients were dilated preoperativelyduring the out patient visit using topicaltropicamide and phenylephrine drops forevaluating the grade of cataract and examiningthe posterior segment. The degree of mydriasiswas recorded. Among them, patients requiringcataract surgery were randomized into twogroups.RandomizationSmall pieces of folded card paper were placed ina bag with words “trial” or “control” written onthem. Once the patient had consented to be a partof the study, a card was picked from the bag bya nurse not involved in the study. At the end of45 minutes mydriasis was recorded on a photoslit lamp using a horizontal slit beam, by anindependent observer who was blinded to themydriatic regimen used. The operating surgeonwas also blinded to the regimen used formydriasis. It was not possible to conceal the armof the trial from the patient because of the natureof the intervention.InterventionGroup A contained 150 patients randomized toreceive mydriatic cocktail delivered with a wick.A mydriatic cocktail was prepared in a sterilecontainer using equal quantities of 2.5%phenylephrine, 1% cyclopentolate, 0.5%moxifloxacin and 0.03% flurbiprofen. All thesolutions were prepared on the day of surgeryusing sterile precautions. Wicks were preparedfrom sterile weck cel sponges and soaked in thecocktail solution for one min. After usingproparacaine to anesthetize the ocular surface,the wicks were placed in the lower fornix usingsterile forceps. The eyes were then taped toprevent the wicks from falling. 4ml of cocktailsolution was sufficient to dilate 10 patientssimultaneously. Mydriasis was assessed with0.5mm intervals, using the Procyon pupillometerunder scotopic conditions (0.04 lux), at 15, 30 and45 minutes.Group B contained 75 patients randomized toreceive the traditional regimen of dilating dropsand served as controls for Group A. The dropsused were 1% cyclopentolate, 2.5%phenylephrine, 0.03% flurbiprofen and 0.5%moxifloxacin. These were instilled topically asone drop from standard droppers. A single dropfrom each group was instilled every threeminutes in succession and the procedure wasrepeated every fifteen minutes for forty fiveminutes. The mydriasis was noted at 15, 30 and45 minute intervals.On the basis of maximal horizontal pupillarydiameter at 45 minutes, patients were categorizedinto three groups, as shown in Table-1.All patients underwent phacoemulsificationusing a scleral tunnel incision by a singlesurgeon. The intra operative pupillary diameterwas noted at two stages in the surgery, afternucleus extraction and after intraocular lensimplantation. The pupillary size was measuredusing Castroviejo calipers.Table-1Category of mydriasis Group A Group B(cocktail) (control)Poor mydriasis (≤5mm) 18 (12%) 15 (20%)Moderate mydriasis (5.1-8mm) 108 (72%) 52 (69%)Good mydriasis (>8mm) 24 (16%) 8 (10%)Results150 patients in group A were dilated with thecocktail regimen and 75 patients in group B weredilated using the conventional topical dropsregimen. The male: female ratio was comparablein both groups with group A having 72:78 andgroup B having 39:36. The mean age in Group Awas 58 years and in group B was 55 years. Ingroup A, 22 patients (15%) had a predisposing

66 AIOC 2009 PROCEEDINGSfactor contributing to poor mydriasis likediabetes or pseudo exfoliation and in Group B,12 patients (16%) had similar predisposingfactors.Both groups were comparable (Table-1) so far ascategory of mydriasis was concerned. Thedilation in both groups was evaluated at 15, 30and 45 minutes. At the 15minute mark, there wasno statistical difference between the two groups.At 30minutes, a difference of 1.57mm betweenthe two groups was significant using theunpaired T test (p

CATARACT SESSION - I67spectrum coverage. Hence all the above drugswere considered in the cocktail.A similar study to ours was done by Ong-Tongusing a 4mm wick for 10 minutes. Itdemonstrated that the wick delivers betterquality of mydriasis as compared to drops. 11However it was not randomized and no formalpupillary measurements were done.Another trial done by McCormick et all reportedpupil dilatation prior to cataract surgery can besafely and effectively achieved using a triangular3 mm pledget sponge soaked in mydriaticdrugs. 12 This trial did not find any statisticallysignificant difference in the mydriasis achievedwith the pledget and the traditional regimen ofdrops contrary to our study. One possibleexplanation is the duration for which the wickwas used. We found maximal mydriasis to beachieved around the 30 minute range and haveevaluated pupillary diameter at 45 minutes asopposed to 20 minutes used by the previousstudy.The main complexity with instilling drops is thatthe average volume per drop is variable with thekind of dropper used. Further the angle ofdispensing the drop has a bearing on each drop’svolume. An acute angle of 45 degree or less couldmean a smaller volume drop with consequently1. Behndig A, Eriksson A: Evaluation of surgicalperformance with intracameral mydriatics inphacoemulsification surgery. Acta Ophthalmol Scand2004;82:144-7.2. Lee YC, Millard J, Negvesky GJ, Butrus SI,Yalkowsky SH. Formulation and in vivo evaluationof ocular insert containing phenylephrine andtropicamide. Int J Pharm. 1999;182:121-6.3. Hirowatari T, Tokuda K, Kamei Y et al: Evaluationof a new pre operative ophthalmic solution. Can JOphthalmol 2005;40:58–62.4. Hirowatari T, Tokuda K, Kamei Y et al: TPDophthalmic solution (mixture of tropicamide,phenylephrine hydrochloride and diclofenac forcataract surgery.) Nippon Ganka Gakkai Zasshi. 2002;106:630-3.5. Sachdev MS, Singh K, Talwar D et al: Comparativeefficacy of diclofenac and flurbiprofen formaintenance of pupillary dilation during cataractsurgery. Oph Surg. 1994;25:92-4.6. Ozturk F, Kurt E, Inan UU, Ilker SS. The efficacy ofReferenceslesser delivery. 14,15 The use of the standard sizewick could perhaps solve some of the problemsassociated with drop volume.This paper demonstrates that dilatation achievedwas superior with the cocktail regimen and theresults obtained were statistically significant.Further, dilation with the cocktail reduced thecost to a third of that incurred using drops. Thepatient comfort and compliance with the cocktailwas better owing to the single application and itsless cumbersome nature. The main potentialbenefit of using this regimen is reduction innursing time required to administer drops. Thedifference between the two groups wasstatistically as well as clinically apparent at the30minute mark but maximal mydriasis wasattained only at 45 minutes. Drawbacks of thisstudy are the lack of formal documentation of thelevels of patient comfort using a formalquestionnaire and the potential risk ofcontamination of the cocktail inherent to thestudy design. Significant results were notobtained in the diabetic and PXF sub-groups dueto small sample size. Our experience suggeststhat the cocktail regimen is much better inmaintaining intraoperative mydriasis in patientswith diabetes and PXF.In conclusion the cocktail regimen is safe,efficacious, time saving and cost effective.2.5% phenylephrine and flurbiprofen combined ininducing and maintaining pupillary dilation duringcataract surgery. Eur J Ophthalmol 2000;10:144-8.7. Hessener V, Schmidt K, Jacobi A: Antiinflammatory effects and aqueous humourconcentration of various non steroidal antiinflammatory drugs in extra capsular surgery. KlinMongrsbl Augenhielkd. 1996;208:161-6.8. Thaller VT, Kulshrestha MK, Bell K et al: The effectof pre operative topical flurbiprofen or diclofenacon pupillary dilation. Eye 2000;14:642-5.9. Power WJ, Hope-Ross M, Mooney DJ et al:Preoperative pupil fatigue. JCRS 1992;18:306-9.10. Eyeson-Annan ML, Him LW, Battistuta D et al:Comparison of pupillary dilation usingphenylephrine alone or in combination withtropicamide. Ophthalmology. 1998;105:726-32.11. Ong-Tone L: Use of wick to deliver pre operativemydriasis for cataract surgery. JCRS 2003;29:2060-2.12. McCormick A, Srinivasan S, Harun S, Watts M.

68 AIOC 2009 PROCEEDINGSPupil dilation using a pledget sponge: arandomized control trial. Clinical and Exptophthalmol. 2006;34: 545-9.13. Luanratanakom, Patanaree et al. Randomized doubleblind study of 2.5% v/s 10% phenylephrine onpupillary dilation. J Med Assoc Thai 2004;87:1380-4.14. German EJ, Hurst MA, Wood D: Reliability of dropsize from multi-dose eye drop bottles: is it cause forconcern. Eye 1999;13:93-100..15. Sklubalova Z, Zatloukal Z: Systematic study offactors affecting eye drop size and dosingvariability. Pharmazie 2005;60:917-21.16. Kato S, Oshika T, Numaga J, Hayashi Y et al:Anterior capsular contraction after cataract surgeryin eyes of diabetic patients. Br J Ophthalmol 2001;85:21-3.17. Rakowska E, Zarnowski T, Zagorski Z. Capsularcontraction syndrome. Klin Oczna 1999;101:375-8.18. Davison JA: Capsule contraction syndrome. JCRS1993;19:582-9.AUTHOR'S PROFILE:DR. ANIL PURUSHOTTAM PATIL: D.O.M.S., B.J.M.C., Pune; D.N.B., Rotary Eye Institute,Navsari, Gujarat. Presently working on fresh Amniotic Membrane grafts in ophthalmology atREI, Navsari.Contact: 9825378935In Vivo Measurement of Lens Volume Using UltrasoundBiomicroscopyDr. Anil Purushottam Patil, Dr. Kamal Nagpal, Mrs. Nilisha Ponkia(Presenting Author: Dr. Anil Purushottam Patil)To study average lens volume usingultrasound biomicroscopy (UBM) in westernIndian population above 25 years of age and indifferent types of cataract.Study designA prospective, observational study.Materials and MethodsAfter obtaining informed consent about thisinvestigational procedure, all subjects wereevaluated using slit lamp examination afterpupillary dilatation with 5% phenylephrine forlens status. Lens status was graded using Lensopacification Classification System (LOCS) IIIscale.a) Grading of lens statusLens status was graded in to two major group1.Clear lens (20eyes) 2.Senile Cataract. Subjectswith senile cataract were further classified in tosubgroups using LOCS III Scale (20eyes in eachgroup) viz. Nuclear, Cortical and Posteriorsubcapsular.b) UBM techniqueUBM examination was carried out in supineposition under topical anaesthesia. The 35 MHz Bmode probe (model C 190030) that allows aresolution of 68 microns was used. The 35 Mhzprobe offers deeper penetration and higherresolution. The system offers the largest scanningfield: 18.5 mm in width and 14 mm in depth.The wide scanning field offers imaging anddiameter measurements of Sulcus-to-Sulcus orAngle-to-Angle, as well as measurements ofcorneal thickness, scleral thickness, lens thicknessand anterior chamber depth and angle indegrees.c) Geometry of lensCrystalline lens is an asymmetrical ellipsoidstructure. So, to calculate its volume we have totheoretically consider lens as a combination oftwo halves of two different ellipsoids.So, we calculated lens volume using formulae-Volume of oblate spheroid 1,2 = 4/3 ╥ ac2, wherea = maximum dimension of major axisc = maximum dimension of minor axisWe used the same formula, to calculate thevolume of two asymmetrical ellipsoidconstructed as shown in figure.Normal lens is considered as p-q-r-s-p, with

CATARACT SESSION - I69pxq1qss1Fig 1: Schematic representation of crystallinelens(pqrsp) as an asymmetrical ellipsoid, two symmetricalellipsoid are constructed viz. pq1rsp and pqrs1p.anterior surface flatter than the posterior lenssurface. So, we constructed 2 ellipsoid, one usinganterior flatter curvature (seen as shadedellipsoid i.e. p-q-r-s1-p.) while the other using theposterior more curved surface (seen as blankellipsoid i.e. p-q1-r-s-p.).Therefore, Volume of p-q-r-s1-p= 4/3ac2a = maximum dimension of major axis i.e.distance p-x.c = maximum dimension of minor axis i.e. q-x.Similarly, the volume of other ellipsoid wascalculated.Thereby, the volume of actual asymmetricalellipsoid (LENS- clear/cataractous) wascalculated using the following formulae.Volume of Asymmetrical ellipsoid (Lens) = ∑ ½volume of two ellipsoid.i.e. Summation of ½ the volume of both theellipsoid so constructed.Inclusion criterion: Consecutive 73 subjectsabove 25years of age irrespective of sex whoattended OPD at Asopalav Eye Hospital with orwithout senile cataract were enrolled in studyafter informed consent.Exclusion criterion: All subjects with thefollowing characteristics were excluded.• Complicated cataract (Steroid induced,uveitis etc)• Any prior history of trauma• Any prior history ocular surgery• History of systemic diseases viz Diabetes,rthyroid/parathyroid disease etc• Known case of Glaucoma• Any clinical evidence of active ocular disease• Presence of any infection in and around eye• Presence of pain or redness (severeintraocular inflammation) in the eye.• Unable to cooperate for UBM• Unable to lie downTo get the accurate measurements the scan wasrepeated after 5 minutes of the initial scan (in asample of 25 eyes). The measurements wererecorded by a single person. The paired t-testshows that the difference in score between thetwo readings is 0.324 and this difference is notstatistically significant (p = 0.496).Results80 eyes of 73 patients were subjected for UBMexamination to study the thickness andequatorial diameter of lens. 57 were males and 23females. Bilateral examination was done in7patients. The correlation of lens volume and theage group is summarised in table 1. The lensvolume distribution according to lens status i.e.Clear crystalline lens and types of cataract isshown in table 2. The average lens volume ofclear lens was 204.48 cumm, cortical cataract-236.4cumm, nuclear-sclerosis-217.2cumm and216.6cumm in posterior-subcapsular cataract.Table-1: Patient’s distribution according to agewith the lens volumeAge Number Mean lens volume Rangegroup of eyes (cumm) (cumm)25-35 11 209.00 191.13-229.9936-45 9 199.29 137.38-216.6046-55 30 224.97 208.45-273.1956-65 16 201.54 204.55-236.4066-75 14 233.76 206.24-260.80The lens appeared as a symmetrical ellipsoid incortical cataract. (Fig 2). However, no significantdifference in volume of lens is seen in variousgrades of nuclear cataract and the posteriorsubcapsular cataract. Lens volume increases withage with minimal decrease seen in 5th decade.DiscussionEllipsoidal shape assumption is a commonapproach for estimating volumes from twodimensionalultrasound images. UBM provides

70 AIOC 2009 PROCEEDINGSTable-2. Lens volume in variable lens statusLens status Clear lens Nuclear sclerosis Cortical cataract Posterior subcapsular cataractNo. of eyes 20 20 20 20Average LensVolume (cumm) 204.48 217.2 236.4 216.6Range (cumm) 182.95-229.99 161.25-316.8 214.73-316.8 137.38-239.17Fig 2: UBM image ofcortical cataractFig 3: Image of Posteriorsubcapsular cataracta unique mean to noninvasively measure the lensvolume. UBM is an excellent tool for in vivomeasurement of lens volume in normalpopulation which may provide a normativedatabase for further clinical implication. Lens1. F. Stuart Foster,1,2 MingYu Zhang et al. In VivoImaging of Embryonic Development in the MouseEye by Ultrasound Biomicroscopy. InvestOphthalmol Vis Sci. 2003;44:2361–6.ReferencesFig 4: UBM image of corticalcataract with Nuclearsclerosis. (Lens assumes asymmetrical ellipsoid inadvanced stage of cataract)Fig 5: UBM image of clearlensvolume found to be more in cortical cataractfollowed by nuclear cataract. Clear lens volumealso increases with age.2. Francis L Rose, Thomas R et al.Measured andpredicted egg volume of Pseudemys texana withcomments on turtle egg shape. Journal of herpetology.1996;30:433-5;.AUTHOR'S PROFILE:Dr. HAIMANTI CHOUDHURY: M.B.B.S. (2002) and M.S. (2007), Silchar Medical College,Assam University, 2002. Presently, Fellow (General Ophthalmology) Sri SankaradevaNethralaya, Beltola, Guwahati-28, Assam.Address: Sunil Sarkar Lane, Silchar-788005; Contact: 9435578982; E-mail: hcee4u@yahoo.comCataract Management in Congenital Coloboma – Our ExperienceDr. Haimanti Choudhury, Dr. Kasturi Bhattacharjee, Dr. Harsha BhattacharjeeDr. H. K. Choudhury(Presenting Author: Dr. Haimanti Choudhury)Lens coloboma is associated withcompromised structural integrity of globeaffecting not only the uvea but also the sclera andzonules. Moreover these eyes are prone toincreased risk of idiopathic retinal detachment.Congenital coloboma itself contributes to poorvision in patients. Development of cataract inthese patients causes further diminution of visionresulting in disability which requires cataractextraction for restoring useful vision. Thoughconventional cataract surgery is performed forlens coloboma, closed chamber technique ofcataract surgery along with intraoperativeexpansion of equatorial capsule helps inmaintaining the integrity of the ocular structureand compartmentalization of eyeball.

CATARACT SESSION - I71The purpose of this study was to evaluate theoutcome of cataract surgery in congenitalcoloboma with phacoemulsification withendocapsular ring and foldable intraocular lensimplantation.Materials and MethodsThis is a prospective non-comparative case seriesof 18 eyes of 18 patients of lens colobomaassociated with retinochoroidal coloboma. Thepatients reported with further progressivediminution of vision attributed to cataract onclinical examination. All these patients hadbilateral ocular malformations and no associatedsystemic disease. The patients were operated in atertiary eye care centre between July 2001 andJune 2007. Examination included visual acuityassessment, detailed anterior segmentexamination and posterior segment examinationwhere media permitted. Horizontal cornealdiameter measurements, intraocular pressureand presence of nystagmus checked in allpatients. Biometry was done in all cases.All the cases were done under peribulbaranaesthesia with 2% lignocaine and 0.5%bupivacaine. Surgical technique includedphacoemulsification with clear corneal incisionopposite to the zone of coloboma. Continuouscurvilinear capsulorrhexis was done in all cases.This was followed by hydrodissection andhydrodelineation where possible. Theendocapsular ring was inserted through the sideport after hydro procedure. Stop and Choptechnique of lens nuclear phacoemulsificationwas done followed by placement of foldableintraocular lens implantation. Patients werereviewed as scheduled in proforma whichincluded visual acuity measurements, refractionand detailed fundus examination to determineposterior extent of coloboma. Follow up rangedfrom 1 year to 7 years.ResultsMean age of 18 cases was 40.16 ± 9.25 years.There were 11 males and 7 females. 12 patientswere below 50 years. These eyes had soft nuclearand cortical cataracts including two with totalcataracts. 6 patients who were more than 50 yearshad brown nuclear cataract. Nystagmus waspresent in 25% patients. There was somedifficulty in assessing correct axial length by Ascan due to the presence of retinochoroidalcoloboma. So B scan was also done forconfirming A scan measurements.Unsatisfactory pupil dilatation was seen in 2cases. Proper dilatation was obtained by injectingviscoelastic into anterior chamber. Size of clearcorneal incision ranged from 2.8 to 3.2 mm.Capsulorrhexis was done under sodiumhyaluronate and could be completed in all but 1case. In that case there was difficulty incontinuing rhexis near area of absent zonuleswhich necessitated use of capsulotomy scissorsto proceed further. Phacoemulsification wasuneventful in 17 cases. Foldable intraocular lenswas implanted in the bag with an injector aftercortical wash. In 1 case there was posteriorcapsular rent with some vitreous loss. Limitedanterior vitrectomy was done with automatedvitrector. Scleral fixated lens was implanted in asecond sitting after 2 months. The endocapsularring was explanted in this case in the first sitting.Postoperatively, there was no seriouscomplication. Striate keratopathy was seen in 2eyes. There was no posterior segmentcomplication either. Visual acuity improved in allcases after 1 month postoperative. Best correctedvisual acuity was 6/9 or better in 11 eyes, 6/12 –6/18 in 5 eyes and 6/24 – 6/60 in 2 eyes. Therewas well compartmentalization of the eyeballwith no vitreous loss in all cases except 1case ofposterior capsular rent. Visual outcome wasdependent on presence of nystagmus, extent ofuveal coloboma posteriorly and pre existingamblyopia. All eyes that had vision better than6/12 did not have nystagmus or retinochoroidalcoloboma extending upto posterior pole.The final vision in all patients was ≥ 6/18, and allthese patients were satisfied with this vision as itwas apparently close to what they could see priorto developing cataract. It was pleasantlyrewarding that they could regain independentmobility and resume most of their daily activities.DiscussionCataract surgery in patients with lens colobomaassociated with retinochoroidal coloboma ischallenging because of anatomical peculiarities,compromised structural integrity of globe andmuch higher risk of complications. Surgeryrequires extra care as every step is potentially

72 AIOC 2009 PROCEEDINGShazardous. Combined A and B scan evaluation isa must both for axial length measurement andprognostication. The results of this study affirmthat clinically significant cataract develops at ayounger age in eyes with congenital colobomathan in eyes with typical nuclear scleroticcataract. Risk of complication is less in youngerpatients with soft cataracts. The use ofendocapsular ring minimizes much of thecomplication which is likely to be associated withcompromised zonules. Phacoemulsificationensures closed chamber technique of cataractsurgery and lens implantation enablescompartmentalization of the globe. Theimproved vision in this study indicates thatphacoemulsification with endocapsular ring andfoldable intraocular lens implantation offers thebest option for patients with typical congenitalcoloboma and cataract.References1. Yu Y.S, Lee J.H, Chang B.L. Surgical managementof congenital cataract associated with severemicrophthalmos. J. Cataract Refract Surg 2000; 26:1219-24.2. Gimbel H.V, Sun R. Clinical applications of capsulartension rings in cataract surgery. Ophthalmic Surg.Lasers 2002;33:44-53.3. Jaffe N.S, Clayman H.M. Cataract extraction in eyeswith congenital coloboma. J. Cataract Refract Surg.1987;13:54-8.4. Nordlund M.L, Sugar A, Moroi S.E.Phacoemulsification and intraocular lens placementin eyes with cataract and congenital coloboma:visual acuity and complications. J. Cataract RefractSurg. 2000;26:1035-40.Biumanual Rhexis in Cataracts with Raised IntralenticularPressureOne of the difficult situations met with duringcapsulorrhexis in hypermature cataracts isthe tendency of the anterior capsular tear to runperipherally. They can be due to the elastic forceof the zonules, intralenticular pressure and thetendency of the anterior chamber to shallow.My focus is on the hypermature cataracts withraised intralenticular pressure. These cataractscontain pockets of fluid cortex which areunconnnected and hence it is not possible tobring down the pressure by simply puncturingor making an incision in the anterior capsule.The raised intralenticular pressure creates atension on the anterior capsule which preventsthe capsulorrhexis from proceeding in thedesired circumferential course. Hence,completing rhexis in such cataracts becomes achallenge.To manage the situation two techniques havebeen described namely two stage rhexis and aspiral rhexis. Aim of this paper is to demonstratea bimanual technique with the help of phacoDr. Ramesh Dorairajan(Presenting Author: Dr. Ramesh Dorairajan)probe and utrata forceps. The underlyingprinciple is bringing down the intralenticularpressure by debulking of the lens material.A mini rhexis of around 2mm is first constructedor a small flap is raised. Before enlarging therhexis , the phaco probe is introduced throughthe main wound. Then, under IA mode, and avacuum setting of around 40mm Hg, the anteriorcortical material is aspirated under the leadingedge of the rhexis. This causes intralenticularvolume to decrease and the capsule to becomeconcave. An added benefit is that the infusionpressure presses down on the capsule andremoves fluid cortex and improves visualization.The less pressure under the anterior capsuleallows the rhexis to proceed centripetally withoutextending to the periphery with the utrataforceps.This two hand technique makes it possible tocomplete the rhexis safely in patients withhypermature cataracts and raised intralenticularpressure.

CATARACT SESSION - I73AUTHOR'S PROFILE:DR. RAKESH KUMAR BANSAL: M.B.B.S., Guru Govind Singh Medical College, Faridkot.Punjabi University Patiala; M.S, P.G.I. Chandigarh, Punjab University, Chandigarh; FRCS (Ed)(2000). Formerly, Deputy Medical Superintendent, GMCH-32, Chandigarh. Recipient ofMuthusamy Gold Medal for best post graduate in FRCS examination, 2000. Presently,Consultant Ophthalmology, GMCH-32, Chandigarh.E-mail: bansalrk@hotmail.comPhotopic and Mesopic Contrast Sensitivity with Spheric, Asphericand Multifocal Intra-Ocular LensesDr. Rakesh K. Bansal, Dr. Archana Malik, Dr. Navneet Tuli, Dr. Sunandan Sood(Presenting Author: Dr. Rakesh K. Bansal)To compare the contrast sensitivity of spheric,aspheric and multifocal intraocular lenses(IOLs).Materials and MethodsIt was a prospective, non-randomized studyconducted on 105 patients between January andDecember 2007 in the department ofOphthalmology at Government Medical Collegeand Hospital, Chandigarh. Thirty three eyes(Group 1) were implanted with monofocalintraocular lens (Sensar), 55 eyes (Group 2) withaspheric IOL (Tecnis Z9003 or Acrysof IQSN60WF) and 17 eyes(Group 3) with multifocalIOL (AcriLISA, Acritec GmbH, Hennigsdorf,Germany).Best corrected visual acuity (BCVA), refraction,intraocular pressure, anterior and posteriorsegment examination was done preoperatively.Patients excluded were those with ocularpathology other than cataract which couldpossibly affect visual acuity or contrastsensitivity like high myopia, diabetic orhypertensive retinopathy, uveitis, maculardegeneration, history of past ocular surgery ortrauma.All surgeries were performed under peribulbaranaesthesia with clear corneal 2.75mm incision.Standard Phacoemulsification was done with inthe bag IOL implantation. All surgeries wereperformed by a single surgeon (RKB). Eyes withany peroperative complication or postoperativetilting or decentration of IOL were excluded fromthe study.Postoperatively all patients were examined at 1day, 1 week, 1 month and 3 months. Contrastsensitivity was measured with best spectaclecorrection after a minimum follow-up of 1month. It was measured using the CSV-1000Econtrast sensitivity charts (Vector Vision) at 3, 6,12, and 18 cycles per degrees (cpd) under bothphotopic conditions (85 cd/m2) and mesopicconditions (5.0 cd/m2).Contrast sensitivity curve was plotted andconverted to log units for each frequency as perVector Vision guidelines. The main outcomemeasure was the difference in contrast sensitivitybetween each IOL group.The statistical comparison of contrast sensitivitylog units between the three groups was doneusing ANOVA and post-hoc bonferroni tests.Data was analyzed with SPSS software (Version11.0).ResultsA total of 105 patients were included in the study.Spherical IOL was implanted in 33 patients,aspheric in 55 and multifocal in 17 patients. Meanage was 61.33±11.10, 62.33±9.06 and 60.05±7.57 ingroup1, 2 and 3 respectively. Mean age of the 3groups was comparable (p=0.567). Male andfemale ratio was similar in all the groups. Bestcorrected visual acuity was ≥ 20/30 in all thepatients.The photopic contrast sensitivity in the threegroups at spatial frequency 3cpd was 1.54±0.25,1.78±0.20 and1.54±0.25; at frequency 6cpd was1.70±0.29, 1.84±0.28 and 1.63±0.26; at frequency12cpd was 1.65±0.38, 1.84±0.41 and 1.54±0.46 andat frequency 18cpd was 1.24±0.30, 1.40±0.41 and1.20±0.45. Aspheric IOLs performed significantlybetter than the multifocal IOLs at frequency

74 AIOC 2009 PROCEEDINGS12cpd. At other frequencies aspheric IOLperformed better than spheric and multifocalIOLs but this difference was not statisticallysignificant.The mesopic contrast sensitivity in the threegroups at spatial frequency 3cpd was 1.62±0.27,1.80±0.25 and 1.56±0.25; at frequency 6cpd was1.76±0.34, 1.98±0.27 and 1.64±0.36; at frequency12cpd was 1.84±0.27, 1.99±0.34 and 1.84±1.08 andat frequency 18cpd was 1.40±0.76, 1.55±0.78 and1.40±0.61. At all frequencies aspheric IOLs hadthe best contrast sensitivity followed by sphericalIOL and multifocal IOLs in that order. Thisdifference was not found to be statisticallysignificant.DiscussionStandard visual acuity is a crude measurementof visual performance and cannot adequatelyrepresent all aspects of visual function. Contrastsensitivity measures two variables, size andcontrast, while visual acuity measures only size.Contrast sensitivity determines the lowestcontrast level which can be detected by a patientfor a given size target.Spherical aberration, a 4th-order aberration is akey contributor to the deterioration of retinalimage due to peripheral rays being focusedanterior to refracted paraxial rays of light.Corneal surface has positive spherical aberration.In youth, crystalline lens has negative sphericalaberration thereby neutralizing the positivespherical aberration of cornea. In elderly,crystalline lens grows, becomes rounder, anddevelops positive spherical aberration, whichadds to the positive corneal spherical aberration.Many previous studies have shown theadvantage of aspheric IOLs over theconventional monofocal or spherical IOLs interms of better contrast sensitivity by negatingthe positive corneal spherical aberration.Caporossi et al 1 compared the contrast sensitivityof various aspheric (Tecnis 9000, Acrysof IQSN60WF, Sofport), and spherical IOLs (AcrysofSN6OAT, Sensar AR40e). Aspheric IOLs showedbetter contrast sensitivity compared to sphericalIOLs at spatial frequencies of 6, 12, and 18 cyclesper degree (cpd) under photopic conditions andat all spatial frequencies under mesopicconditions. Another study done by Bellucci et al 2to compare aspheric (Tecnis Z9000) with spheric(Acrysof SA60AT) IOL yielded similar results.Aspheric IOL performed better at all spatialfrequencies under both photopic and mesopicconditions but the difference was clinicallysignificant at higher frequencies.Our results arecomparable to these studies.Patients with multifocal IOLs although havebetter uncorrected near vision have been foundto have low contrast sensitivity. Kim et al 3conducted a study to compare the higher orderaberrations and contrast sensitivity of monofocaland multifocal IOLs. Multifocal IOLs wereassociated with higher spherical aberrations andhad lower contrast sensitivity at all spatialfrequencies. Another study done by Zeng M etal 4 to compare the aberrations and contrastsensitivity between aspherical, monofocal andmultifocal IOLs showed that multifocal IOL wasassociated with maximum spherical aberrationand least contrast sensitivity. Aspheric IOLs wereseen to have least spherical aberration andmaximum contrast sensitivity. Spheric IOLs werein between the two.Our study showed similar results with maximumcontrast sensitivity in eyes with aspheric IOLfollowed by spherical IOLs and least withmultifocal IOLs.Asperical IOLs give better contrast sensitivitycompared to spherical and multifocal IOLs.1. Caporossi A.et al. Prospective randomized study ofclinical performance of 3 aspheric and 2 sphericalintraocular lenses in 250 eyes. J Refract Surg.2007;23:639-48.2. Bellucci R, Scialdone A, Buratto L et al. Visual acuityand contrast sensitivity comparison between Tecnisand AcrySof SA60AT intraocular lenses: Amulticenter randomized study. J Refract Surg.2005;31:712-7.References3. Kim CY, Chung SH, Kim T et al. Comparison ofhigher order aberrations and contrast sensitivity ofmonofocal and multifocal intraocular lenses. YonseiMed J. 2007;48:627-33.4. Zeng M, Liu Y, Liu X et al. Aberration and contrastsensitivity comparison of aspherical, monofocal andmultifocal IOLs. Clin Experiment ophthalmol 2007;35:355-60.

CATARACT SESSION - I75AUTHOR'S PROFILE:DR. ABHAYKUMAR R. VASAVADA: M.S. (’75) University, Baroda; F.R.C.S. (Eng.) (’80).Recipient of (i) B.C. Roy Award, (ii) Asia Pacific Association of Cataract and RefractiveSurgeons Educator Award (2002). Published 135 publications in peer reviewed journals.Presently, (i) Director (Medical) and Phacosurgeon Raghudeep Eye Clinic, (ii) Director(Research), Iladevi Cataract and IOL Research Centre, of Gurukul, Memnagar, Ahmedabad,Gujarat.Contact: (079) 27490909; Email: icirc@abhayvasavada.comComparison of Torsional (Ozil) Versus MicroBurst Longitudinal(Traditional) Phacoemulsification - A Prospective RandomizedMasked Clinical TrialDr. Abhay R. Vasavada, Dr. Nirmit V. Dixit, Dr. Shetal M. Raj, Dr. Udayan Patel(Presenting Author: Dr. Nirmit V. Dixit)The latest generations of phacoemulsificationmachines provide a variety of optionsutilizing advanced power modulation ofultrasound energy and improved fluidic control.Introduced in mid 2006, torsional ultrasound(OZil, Infiniti Vision System, Alcon Laboratories,Texas, USA) uses rotational oscillations atultrasonic frequencies to emulsify cataractouslens material in a seamless cutting motion from atip that oscillates laterally. The side-to-sidemovement of the phaco tip produces minimalrepulsion of lens material from the phaco tipresulting in improved followability. Because ofthese observed intra-operative improvements,this study was undertaken to quantitativelycompare the intra-operative efficacy and postoperativeoutcome of torsional ultrasoundagainst modulated longitudinal ultrasound usingdifferent system and device configurations.Materials and MethodsA prospective, randomized, single masked studythat included patients undergoing routinephacoemulsification for age-related cataract wasconducted at Iladevi Cataract and IOL ResearchCentre, Ahmedabad, India. Patients 55 years andolder with senile cataract grades 1 to 5 nuclearsclerosis based on Emery’s classification,endothelial cell density > 1500 cells/mm2,anterior chamber depth > 2.4 mm, and a dilatedpupil > 7 mm were included in the study. Eyeswith pseudoexfoliation, mature, traumatic, orcomplicated cataracts, history of previous intraocularsurgery, glaucoma, uveitis, and patientswho were unable to comply with follow-upexaminations were excluded.The recruitedpatients were examined pre-operatively througha slit lamp biomicroscope under completemydriasis. The eyes in each group wererandomized by a computer-generated list in a 1:1ratio into 3 treatment groups: group 1: torsionalultrasound (OZil); group 2: microburst withlongitudinal ultrasound (Infiniti Vision System);and group 3: microburst with longitudinalultrasound (Legacy Everest, Alcon Laboratories,Fort Worth, Texas, USA).Surgical ProcedureAll surgeries were performed by a singleexperienced surgeon (ARV) with a standardtechnique. For torsional ultrasound, themaximum amplitude was set to 100%. Forlongitudinal ultrasound, parameters used duringdifferent stages of surgery varied according tothe density of the nuclear sclerosis. Themicroburst mode was used with both the Infinitiand the Legacy Everest with the burst width setbetween 10 and 30 milliseconds and a subsequentoff time of 0 milliseconds. In all groups, thevacuum limit was preset between 250 and 650mmHg with aspiration flow rate between 20 and30 cc/minute. The bottle height was raised to amaximum of 110 cm from a minimum of 90 cmduring the stage of fragment and epinucleusremoval.AssessmentsIntra-operative assessments include surgicalclock time (SCT, minutes) and fluid volume used(FV, ml). Central corneal thickness (CCT) wasmeasured pre-operatively with an ultrasonic

76 AIOC 2009 PROCEEDINGSpachymeter (Ocuscan, Alcon Laboratories, FortWorth,Texas, USA). The central corneal densityimage was taken using non-contact specularmicroscopy (Kowa, Add city and Country). CCTchanges (m) were measured post-operativelyon the first day, one month, and three monthswith respect to pre-operative values. Thepercentage decrease in ECD at three months andabsolute change in CV at three months werecalculated with respect to pre-operative valuesamong the three groups.A single observer whowas masked to the allocated group was assignedto measure the CCT and ECD to avoid interobservervariation. Kruskal-Wallis test was usedto compare SCT, FV, CCT changes, ECD, and CV.Post hoc pair wise comparisons were also usedfor analysis. The test of proportion was used tocompare the corneal clarity in the torsional groupwith each of the longitudinal groups separately.ResultsA total of 360 eyes of 360 patients were included.All patients were examined at the last follow up.Table 1 shows the demographics and preoperativeparameters per treatment group. Theywere similar among the groups (P > .05). Table 2summarizes the intra-operative performance pertreatment group. By pair wise comparison, SCTand FV were statistically significantly less fortorsional ultrasound compared to the other twotreatment groups.The percentage of individualswith clear cornea on the first post-operative daywas significantly higher in the torsionalultrasound group (100%) compared to 93% in themicroburst longitudinal ultrasound Infinitigroup (P = .01, test of proportion) and 76% in themicroburst longitudinal ultrasound Legacygroup (P = .001, test of proportion) Table 3illustrates the change in CCT at post-operativeday 1, and months 1 and 3, and ECD and CV at 3months. For eyes in the torsional ultrasoundgroup, the increase in CCT and endothelial cellloss was statistically significantly less, ascompared to either longitudinal ultrasoundgroup. Corneal thickness in the torsionalultrasound group also returned to pre-operativevalues sooner.DiscussionWhen using a torsional handpiece and angledphaco tip, the phaco tip oscillates and creates aside-to-side movement of the tip at the distal endof the phaco tip. These oscillations remove thelens substance by surface shearing which is moreeffective than the jackhammer cutting action oflongitudinal ultrasound. The continuousmovement of the torsional tip is more effective atemulsifying (i.e., improved cutting efficiency)because both movements side-to-side canremove and emulsify lens material. Ourexperience demonstrates that we can create arapid central working space within the verydense lenses in the torsional group.As measured in this study, shorter SCTs andTable-1: Demographic distribution and pre-operative central corneal thickness, endothelial cell densityand coefficient of variation per treatment groupGroup 1 Group 2 Group 3 P valueTorsional U/S Longitudinal U/S Longitudinal U/S(n=120 eyes) (Infiniti) (Legacy)(n=120 eyes) (n=120 eyes)Age (years) Mean ± SD 65.8 ± 8.8 69.8 ± 8.2 63.6 ± 8.7 .619*Range 56 – 85 58 – 89 55 – 86CCT (µm) Mean ± SD 544 ± 38 537 ± 24.0 538 ± 35 .512§Range 481 - 596 474 - 583 479 - 598ECD (cells/mm2) Mean ± SD 2891 ± 378 2690 ± 338 2732 ± 400 .523§Range 2396 - 3566 2229 - 3764 2287 - 3771CV (%) Mean ± SD 42 ± 2 39 ± 6 38 ± 7 .522§Range 38 - 46 27 - 48 24 - 44Nuclear density Mean ± SD 3.13 ± 1.3 3.34 ± 1.33 3.20 ± 1.29 .513§Range 1 - 5 1 - 5 1 - 5U/S, ultrasound; SD, standard deviation; CCT, central corneal thickness; ECD, endothelial cell density; CV, coefficientof variation. * ANOVA test; §, Kruskal Wallis test.

CATARACT SESSION - I77Table-2. Intra-operative performance per treatment group.U/S, ultrasound; SD, standard deviationGroup 1 Group 2 Group 3Torsional Longitudinal Longitudinal P ValueU/S (n=120) U/S (Infiniti) U/S (Legacy) (Kruskal(n=120) (n=120) Wallis test) Pairwise omparison1 vs. 2 2 vs.3 1 vs. 3Surgical cloc Mean . 4.40±1.37 6.65±2.48 7.05±3.38 .05 < .05time (minutes) ± S.DRange 1.5 – 7.8 3.1 – 11.7 3.4 – 16.3Fluid volume Mean ±used (ml) S.D. 101±40.44 125±37.76 135±73.14 0.001 < .05 > .05 < .05Range 50 – 178 77 - 220 82 - 255Intra-operativecomplications No No NoTable-3. Comparison of the corneal clarity, central corneal thickness, endothelial cell density, andcoefficient of variation among the groups overtimeGroup 1 Group 2 Group 3Torsional Longitudinal Longitudinal P ValueU/S (n=120) U/S (Infiniti) U/S (Legacy) (Kruskal(n=120) (n=120) Wallis test) Pairwise omparison1 vs. 2 2 vs.3 1 vs. 3Increase in Mean±SD 67.2 ±21.0 83.6 ± 49.0 89.4 ±62.0 .03 < .01 NS

78 AIOC 2009 PROCEEDINGSand the ability to use lower aspiration parameterswhich would not be possible with microburstlongitudinal ultrasound. As there is minimal orno repulsion of fragments with torsionalultrasound, low to modest aspiration parameters(e.g. 20-30 cc/min) were found to be surgicallyefficient and sufficient to achieve effectiveremoval which also reduces intraoperativeturbulence. The quicker recovery of the cornea asmeasured by the decreasing levels of cornealthickness on sequential post-operativeevaluations and the low endothelial cell loss inthe torsional ultrasound group suggest minimalintra-operative trauma inflicted by torsionalphacoemulsification.In summary torsional is an improved ultrasoundphacoemulsification modality with increasedefficacy and safety that provides intra-operativetime savings and good post-operative outcomesin regard to endothelial cell loss and cornealcondition when compared to the traditionalmodulated longitudinal ultrasound.