ARVO 2015 Annual Meeting Abstracts

Transcription

1 383 Corneal surgery, refractive Tuesday, May 05, :45 PM 5:30 PM Exhibit Hall Poster Session Program #/Board # Range: /D0115 D0157 Organizing Section: Cornea Program Number: 3910 Poster Board Number: D0115 New flap creation using the Ziemer LDV femtosecond laser in patients with a history of LASIK surgery. Nathan J. Abraham 1, Thomas Tooma 2. 1 Internal Medicine, Eisenhower Medical Center, Rancho Mirage, CA; 2 NVISION Laser Eye Centers, Newport Beach, CA. Purpose: Epithelial ingrowth following LASIK surgery has been reported to occur from 0% to 20%, with clinically significant ingrowth as frequently as 8% following a flap re-lifting technique. We performed a retrospective, observational chart analysis focusing on clinical outcomes and incidence of epithelial ingrowth for patients that received LASIK enhancement surgery using the Ziemer LDV CrystalLine femtosecond laser. We hypothesize that creating a new flap using the femtosecond laser produces clinically favorable refractive outcomes and minimizes the risk of epithelial ingrowth in LASIK enhancement. Methods: Charts of LASIK enhancements performed from November 2012 through June 2014 were reviewed. A total of 97 eyes from 62 patients were included; 30 males (52 eyes) and 32 females (45 eyes). The average time between original LASIK and enhancement was 10 years. Follow-up end points ranged from one month to one year. The paired t-test was used for statistical analysis. Results: Highly favorable refractive outcomes were observed following enhancement. The average LogMAR UDVA was improved from (SD 0.244) to (SD 0.082) following enhancement LASIK. The mean LogMAR UDVA was significantly improved and remained stable throughout follow up (average reduction of , SEM 0.02, P <0.0001, n = 97). The average depth of the original flap was 130 microns. The depth of the enhancement flap was either 100, 110, or 140 microns (29 cases of 140 flap thickness; below the original flap). Method of original flap creation was noted; Intralase (39), Ziemer (5), and microkeratome (Hansatome 36 and ACS keratome 17). Original LASIK correction was performed on 76 myopic eyes and 21 hyperopic eyes. There were no postenhancement surgical complications noted, with only one case of clinically insignificant epithelial ingrowth (<1mm in the periphery), not requiring intervention. Our results confirm the hypothesis supporting novel flap creation using the femtosecond laser in LASIK enhancement. Conclusions: Creation of a new flap using the femtosecond laser for LASIK enhancement produces stable and reproducible improvements in visual acuity with a negligible side effect profile. Our results confirm that the Ziemer LDV CrystalLine femtosecond laser can be used as a safe and highly efficacious method for new flap creation in LASIK enhancement. LASIK enhancement with new flap formation improves UDVA. Commercial Relationships: Nathan J. Abraham, None; Thomas Tooma, NVISION Laser Eye Centers (I) Program Number: 3911 Poster Board Number: D0116 Comparing laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) with Mitomycin C for high myopia Jessica L. Mather 1, Andrew Holzman 2, 3, James Smeriglio 3. 1 Dept. of Ophthalmology, Georgetown University Hospital/ Washington Hospital Center, Washington, DC; 2 Ophthalmology, Georgetown University Hospital, Washington, DC; 3 The Laser Center (TLC), Rockville, MD. Purpose: Although both PRK and LASIK are possible treatment options for high myopia, there have been concerns for development of corneal haze with PRK. The advancement of Mitomycin C (MMC) as a preventative measure in PRK has allowed greater myopic refractive errors to be attempted. This retrospective study specifically compares outcomes of patients with high refractive errors of or greater who received LASIK or PRK with MMC. We hypothesized that PRK with MMC is as effective as LASIK and the risks of corneal haze are much lower than previously suggested. Methods: This retrospective study reviewed charts from TLC locations in Rockville, MD and Tyson s Corner, VA. All procedures were performed by Dr. Andrew Holzman between The Wavelight Allegretto Wave 200 Hz excimer laser was used on all patients. A total of 166 eyes (86 LASIK eyes and 88 PRK eyes) with at least a spherical equivalent of or greater were reviewed. Any patients with underlying eye disease or previous refractive surgery were excluded. Oucome measures included: uncorrected distance visual acuity, best corrected visual acuity, patient satisfaction, corneal haze, and post-operative complants. Results: On post operative day 1, vision was better in LASIK patients over PRK with a mean LogMar UCVA of <0.1 (> 20/25) versus 0.4 (20/50) for PRK (p<0.0001). By week 1, there was a much smaller gap in LASIK and PRK patients with uncorrected visual acuity (LogMar) for LASIK patients being 0.05 (>20/25) and <0.2 (>20/30) for PRK patients (P<0.0001). Both LASIK and PRK groups had a mean LogMar UCVA <.0.01 (>20/25) by post op month 1 (P<0.0032). Post op months 3 and 6 showed similar data with

2 both groups having LogMar UCVA <0.1 (>20/25) with p=0.142 and P< respectively. Of all patients who underwent PRK, only 4 had any mention of corneal haze. Two of these cases were described as mild. Three of these patients only had haze mentioned at 1 visit, and only one patient had persistent corneal haze at post operative month 11. Conclusions: LASIK results in better immediate post operataive uncorrected visual acuity in high myopes. By one month post operative, the mean UCVA in both groups was similar and better than 20/25. At 3 months and 6 months, both LASIK and PRK with MMC have excellent results with similar outcomes (> 20/25). PRK with MMC has significantly reduced the presence of corneal haze in high myopes. Commercial Relationships: Jessica L. Mather, None; Andrew Holzman, Alcon (C), TLC (E); James Smeriglio, TLC (E) Program Number: 3912 Poster Board Number: D0117 Long-term ocular surface outcomes and in vivo corneal confocal microscopy in patients with mechanical microkeratome vs femtosecond laser-assisted LASIK Munira Hussain, Thais S. Tanaka, Jonathan B. Greene, Shahzad Mian, Roni M. Shtein. Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI. Purpose: To compare clinical outcomes and subbasal corneal nerves in patients 8 to 10 years after laser in situ keratomileusis (LASIK) with flap creation by microkeratome (MK) or femtosecond laser (FL) Methods: Prospective, comparative, IRB approved study of 90 eyes of 47 patients who underwent myopic LASIK, with either MK or FL flap. Corneal fluorescein staining, tear break up time (TBUT), tear osmolarity, central corneal thickness (ultrasound pachymetry), corneal sensation (Cochet-Bonnet esthesiometry), tear production (Schirmer test), Ocular Surface Disease Index (OSDI) and subbasal corneal nerves by in vivo confocal microscopy (IVCM) were assessed in all subjects. Two-tailed t-tests and Fishers s exact test were performed to compare subjects with MK and FL. P-value less than 0.05 was considered statistically significant. Results: Flap creation was performed with MK in 47 eyes and with FL in 43 eyes. Mean age was 52.5 years in the MK group and 51.7 years in the FL group (p=0.75). Assessment at 8-10 years after surgery indicates a trend towards fewer corneal nerves (6.3 vs 7.8 nerves per image, p=0.053) and lower nerve density (9.3 mm/mm 2 vs 12 mm/mm 2, p=0.065) in the FL group. There were no significant differences in OSDI scores (p=0.866), tear osmolarity (p=0.285), schirmer (p=0.415), TBUT (p=0.927), corneal thickness (p=0.117), corneal sensation (p=0.118) and fluorescein staining (p=0.175) between the two groups. Conclusions: Our preliminary results indicate that there is a trend towards differences in the number of corneal nerves and nerve density. There may not be long-term differences in standard measures of ocular surface health (tear osmolarity, Schirmer, fluorescein stain, OSDI) between patients who had the two techniques of LASIK flap creation. Commercial Relationships: Munira Hussain, None; Thais S. Tanaka, None; Jonathan B. Greene, None; Shahzad Mian, None; Roni M. Shtein, None Program Number: 3913 Poster Board Number: D0118 Comparison of Centration between Pupil Center and Corneal Vertex for LASIK Surgeries Guang-ming G. Dai 1, Dimitri Chernyak 1, Daniel R. Neal 1, Steven C. Schallhorn 2, 3. 1 R & D, Abbott Medical Optics, Milpitas, CA; 2 Chief Medical Director, Optical Express, London, United Kingdom; 3 Ophthalmology, University of California, San Francisco, CA. Purpose: To compare and contrast two LASIK treatment centration methods (pupil centration and corneal vertex centration) in terms of optical effects and visual outcomes. The treatments considered are based on wavefront, corneal topography and Munnerlyn equation. Methods: Two types of analysis methods are used for determining effects of centration method: optical modeling and clinical data evaluation. With optical modeling, induction of low-order and high-order aberrations (HOAs) is examined for both centration methods. Wavefront diameter of 6 mm is used for the analysis. With clinical data, post-operative high-order aberrations (in particular coma and spherical aberration) and visual acuities are correlated with pre-operative decentration parameters, such as the angle kappa. Wavefront analysis was done over 6 mm and 5 mm diameter, respectively. Results: Optical modeling shows a significant induction of coma with corneal vertex centration, because of the incorrect placement of the ablation profile. Likewise, a significant induction of cylinder error is present. No such induction of coma and cylinder is seen with pupil centration. With clinical data analysis, no correlation can be found between 6-month post-operative uncorrected and best corrected acuities, HOAs, with pre-operative angle kappa. Between

3 two sub-groups with large (>= 0.55 mm) and small (<= 0.25 mm) angle kappa, no statistically significant difference in terms of coma, spherical aberration, and high order RMS can be found. In addition, LASIK with pupil centration has the following advantages: easier to perform, utilizing all of the light going through the pupil aperture, does not impact the vision of patients with large angle kappa, does not induce higher order aberrations, and is optimal for wavefrontguided procedures. Conclusions: The study shows the centration method over the entrance pupil has more advantages compared to the corneal vertex centration for all types of LASIK surgeries. Commercial Relationships: Guang-ming G. Dai, Abbott Medical Optics (E); Dimitri Chernyak, Abbott Medical Optics (E); Daniel R. Neal, Abbott Medical Optics (E); Steven C. Schallhorn, Abbott Medical Optics (C), Optical Express (E), University of California, San Francisco (E) Program Number: 3914 Poster Board Number: D0119 Laser refractive surgery centration: visual axis or line-of-sight? Daniel R. Neal, Thomas D. Raymond, Wei Xiong, Richard J. Copland. Research and Development, AMO WaveFront Sciences, LLC, Albuquerque, NM. Purpose: Since the eye is not a centered optical system, there has been a debate over the correct location for centering a laser refractive surgical treatment. The cornea has a well-defined axis and center and yet it is not co-located with the pupil. It has been observed in some cases that aberrations may be induced for a decentered pupil. Methods: Aberrations were modeled centered on the cornea with different amounts of induced aberrations. These were compared to published literature results for induced aberrations for four different laser platforms. Results: The models indicate that there is a significant coupling between spherical aberration and coma for off-axis pupils if the spherical aberration (SA) is assumed to be centered on the cornea. This matches the clinical results for the cornea centered laser systems, but not the results for the pupil centered systems. For a typical (6 mm pupil) um RMS corneal spherical aberration induced by a conventional LASIK treatment, the resulting coma is 0.37 um for a centered pupil verses 0.62 um for a decentered pupil. Using only the spherical aberration term and centering the treatment on the corneal vertex, the simulation predicted 0.35 um RMS coma, in excellent agreement with the clinical results. Conclusions: The desired centration is more a property of the design of the laser delivery system than of the eye itself. While the eye may have a significant coupling between aberrations on the cornea and on the pupil, the individual laser system may take these effects into account. Residual errors may be due, in part, to remodeling of the epithelial layer after healing, and hence be somewhat unpredictable. Figure 1 Optical simulation of induced coma caused by decentered pupil with corneal-vertex-centered spherical aberration. The corneal aberration was 0.25 um RMS over 6mm pupil and the predicted coma was 0.35 um RMS for a 0.6 mm decentration. Figure 2 Simulation of various aberrations as a function of pupil decentration. Spherical aberration does not change with decentration, however, coma and astigmatism can change significantly, even for fairly small decentrations. Commercial Relationships: Daniel R. Neal, Abbott Medical Optics (E), Zeiss Meditec (P); Thomas D. Raymond, Abbott Medical Optics (E); Wei Xiong, Abbott Medical Optics (E); Richard J. Copland, Abbott Medical Optics (E) Program Number: 3915 Poster Board Number: D0120 Corneal aberrations and its effect on contrast sensitivity after wavefront-guided and wavefront-optimized refractive surgeries Rose K. Sia 1, Lamarr Peppers 1, Denise S. Ryan 1, Richard Stutzman 2, Joseph F. Pasternak 2, Jennifer B. Eaddy 1, Lorie A. Logan 1, Bruce Rivers 1, Kraig S. Bower 3. 1 Warfirghter Refractive Eye Surgery Program and Research Center, Fort Belvoir, VA; 2 Ophthalmology, Walter Reed National Military Medical Center, Bethesda, MD; 3 Ophthalmology, Wilmer Eye Institute, Baltimore, MD. Purpose: To evaluate the changes in corneal aberrations following wavefront-guided (WFG) and wavefront-optimized (WFO) refractive surgeries and determine the effect of postoperative corneal aberrations on contrast sensitivity.

4 Methods: In a prospective study, active duty U.S. military service members with mean age 30.1±6.1 years and refractive error -3.74±1.40 diopters (D) undergoing either PRK or LASIK were randomized to receive either WFG (n=51) or WFO (n=56) treatment. WFG treatment was performed using the VISX CustomVue STAR S4 IR and WFO with Wavelight Allegretto Wave Eye excimer laser system. Corneal aberrometry parameters were analyzed using the Oculus Pentacam system. The root mean square (RMS) of spherical aberration (SA), higher order aberrations (HOA) and total aberrations (TA) were calculated for a pupil diameter of 6.0 mm. Contrast threshold was measured preoperatively with correction and postoperatively without correction using the Metropsis Visual Stimulus Generation Device at five different spatial frequencies and area under the log contrast sensitivity function (AULCSF) was calculated. Paired sample t-test was used to compare pre- and postoperative changes. Linear regression analysis was used to explore the effect of corneal aberrations and treatment performed on contrast sensitivity. Results: Corneal SA and HOA significantly increased at 6 months following either WFG or WFO refractive surgery. The mean difference in SA was 0.47 mm, P<0.01 and HOA was 0.54 mm, P<0.01 in WFG group while the mean difference in SA was 0.54 mm, P<0.01 and HOA was 0.46 mm in the WFO group. TA did not change significantly after either treatment (P>0.22). The AULCSF did not change significantly 6 months after either WFG or WFO refractive surgery (P>0.42). The changes in corneal SA, HOA and TA as well as the surgery performed were not significantly associated with the changes in AULCSF (P=0.08). Conclusions: Both WFG and WFO refractive surgeries significantly induce changes in corneal spherical aberration and higher order aberrations but not in contrast sensitivity function. Corneal aberrations induced by WFG and WFO refractive surgeries appear to have no significant effect on postoperative contrast sensitivity. Commercial Relationships: Rose K. Sia, None; Lamarr Peppers, None; Denise S. Ryan, None; Richard Stutzman, None; Joseph F. Pasternak, None; Jennifer B. Eaddy, None; Lorie A. Logan, None; Bruce Rivers, None; Kraig S. Bower, None Support: Dept of Defense W81XWH Clinical Trial: NCT Program Number: 3916 Poster Board Number: D0121 Wavefront-Optimized LASIK and PRK in Patients with High Astigmatism Kaidi Wang, Edward E. Manche. Ophthalmology, Stanford, Palo Alto, CA. Purpose: To compare efficacy of wavefront-optimized LASIK and PRK in patients with baseline cylinder of 2.00 or greater. Methods: In this retrospective study, 34 eyes of 24 consecutive patients with a baseline cylinder of 2.00 or greater who underwent wavefront-optimized LASIK or PRK with Alcon Wavelight Allegretto Eye-Q 400 excimer laser were analyzed. All eyes were targeted for emmetropic vision. Results: Six months after LASIK, 10/23 eyes were lost to follow up. Of the remaining, 9/13 had uncorrected distance visual acuity (UDVA) of 20/40 or better and 5/13 had 20/25 or better. 2 eyes gained one or more lines of best-corrected distance visual acuity (CDVA). No eyes lost any lines of CDVA. Mean preop spherical equivalent decreased from /-2.43 diopters (range 8.0 to 2.5) to /-0.53 (-1.75 to 0). Mean cylinder decreased from 3.61+/-0.99 diopters (2.00 to 5.25) to 0.37+/-0.32 (0 to 1.0). Wavefront analyses revealed an increase in higher order aberrations from preop RMS error of / (0.13 to 0.54) to / (0.14 to 0.67). Coma increased from / (0.04 to 0.44) to / (0.05 to 0.42). Trefoil decreased from /-0.08 (0.03 to 0.29) to / (0.01 to 0.23). Spherical aberration decreased from / (-0.13 to 0.41) to / (-0.18 to 0.58). Six months after PRK, no eyes were lost to follow up. 10/11 eyes achieved 20/40 UDVA or better and 8/11 achieved 20/25 or better. 4 eyes gained one or more lines of CDVA. 2 eyes lost one line of CDVA. Mean preop spherical equivalent decreased from /-4.00 diopters (range to 3.63) to /-0.51 (-0.88 to 0.75). Mean cylinder decreased from 3.53+/-0.87 diopters (2.00 to 5.25) to /-0.40 (0 to 1.25). Wavefront analyses revealed an increase in higher order aberrations from preop RMS error of / (0.12 to 0.43) to / (0.28 to 0.70). Coma increased from / (0.03 to 0.33) to / (0.09 to 0.48). Trefoil increased from 0.17+/-0.08 (0.03 to 0.33) to / (0.10 to 0.43). Spherical aberration decreased from / (-0.07 to 0.30) to 0.02+/ (-0.32 to 0.30). Conclusions: Both LASIK and PRK are effective in eyes with high baseline cylinder. There is a trend towards increased higher order aberrations post-lasik or PRK surgery. Commercial Relationships: Kaidi Wang, None; Edward E. Manche, None Program Number: 3917 Poster Board Number: D0122 Topography guided treatment of irregular astigmatism: visual and refractive outcomes after corneal transplant Joaquim N. Murta 1, 2, Andreia Rosa 1, 2, Maria J. Quadrado 1, 2, Marta G. Guerra 1, 2, Inês Lains 1, 2. 1 Ophthalmology, University Coimbra, Coimbra, Portugal; 2 Ophthalmology, Centro Hospitalar Universitário Coimbra, Coimbra, Portugal. Purpose: To analyse the visual and refractive outcomes of topography-guided photorefractive keratectomy (PRK) to treat irregular astigmatism following penetrating keratoplasty (PK). Methods: Retrospective case-series study. After accessing our database, eyes submitted to topography-guided PRK (Allegretto WaveTM Eye-Q, WavelightTM, Erlangen, Germany) with Topography-guided Customized Ablation Treatment software (T-CAT) after PK, were identified and medical records reviewed. Patients with follow-up less than 3 months and history of other ocular comorbidities or interventions were excluded. Pre and postoperative clinical data were collected, namely uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, topography parameters obtained with Orbscan IIz system (Bausch & Lomb, Rochester) and endothelial cell density. Results: Thirty-one eyes of 30 patients, mean aged ± years, with mean follow-up of 9.18 ± 8.24 months, were included. There was a significant improvement of UCVA (0.95±0.27 logmar preoperatively versus 0.38±0.30 logmar postoperatively, p<0.001) and BCVA (0.25±0.16 and 0.15±0.19 logmar respectively, p=0.004). At last follow-up, 66.6% of the eyes had gained UCVA lines and 14.8% had lost. Refractive parameters also presented a significant improvement, with the refractive cylinder decreasing from 6.35±2.21 preoperatively to 1.96±1.14 postoperatively (p<0.001) and the spherical equivalent (SE) improving from -3.36±3.68 to -1.11±1.63 diopters, (p=0.002). In the last visit, 53.8% of the eyes presented SE among ± 1diopter. There was no significant decrease in endothelial cell density. Conclusions: Topography-guided ablation is an efficient and safe treatment for irregular astigmatism and high ametropia after penetrating keratoplasty. Most patients improved visual acuity and refractive parameters.

5 Commercial Relationships: Joaquim N. Murta, None; Andreia Rosa, None; Maria J. Quadrado, None; Marta G. Guerra, None; Inês Lains, None Program Number: 3918 Poster Board Number: D0123 Astigmatism Vector Analysis Comparing Laser In Situ Keratomileusis Flap Creation Using 150kHz and 60kHz Femtosecond Laser Platforms Brian C. Toy, Edward E. Manche. Byers Eye Institute, Ophthalmology, Stanford University Hospital and Clinics, Fremont, CA. Purpose: To compare the astigmatic outcomes of laser in situ keratomileusis (LASIK) with flap creation using either a 150kHz or a 60kHz femtosecond laser platform. Methods: 122 eyes of 61 patients underwent LASIK for compound myopic astigmatism with the Abbott CustomVue S4 excimer laser platform (Abbott Medical Optics, Santa Ana, CA), Flap creation was performed using the Abbott Intralase femtosecond laser platform, and one eye used the Abbott Intralase FS60 60kHz laser, while the contralateral eye used the Intralase ifs 150kHz laser. Preoperative and postoperative assessments were performed and included manifest refraction, vector analysis, topography, and wavefront aberrometry. Eyes were stratified for subgroup analysis based on preoperative manifest astigmatism: , , and diopters. Statistics were calculated using t-tests. Results: Preoperatively, mean spherical equivalent (SE) was -4.3±2.3 vs -4.3±2.3 diopters(d) (p=0.89), and mean cylindrical error(ce) was 0.6±0.7 vs 0.6±0.4D (p=0.74) in the FS60 60kHz and ifs 150kHz groups, respectively. At postoperative month 12, mean SE was -0.3 ±0.3 vs -0.2±0.3D (p=0.22), and mean CE was 0.1±0.2 vs 0.2±0.2D (p=0.13), respectively. Alpins vector analyses for the FS60 60kHz and ifs 150kHz groups, respectively, were: surgically-induced-astigmatism (0.6±0.6 vs 0.6±0.4D, p=0.78), magnitude of error (0.1±0.1 vs 0.1±0.2D, p=0.21), angle of error (7±19 vs 11±23, p=0.33), correction-index (1±0.3 vs 1±0.3, p=0.67), success-index (0.4±0.9 vs 0.5±1, p=0.45), and flattening-index (0.9±0.3 vs 0.8±0.5, p=0.44). Subgroup analysis by preoperative astigmatism showed no significant differences. Conclusions: Minimal difference in outcomes between FS60 60kHz and ifs 150kHz platforms based on objective Alpins analysis of astigmatism. Commercial Relationships: Brian C. Toy, None; Edward E. Manche, Best Doctors (I), Calhoun Vision (I), Gerson Lehman (I), Krypton Vision (I), Refresh Innovations (I), Seros Medical (I) Clinical Trial: NCT Program Number: 3919 Poster Board Number: D0124 Keratometric outcomes for femtosecond laser-assisted limbal relaxing incisions Phillip Rubin 1, Matthew Gorski 2, 3, Carolyn Shih 2. 1 Hofstra North Shore-LIJ School of Medicine, Hempstead, NY; 2 Ophthalmology, North Shore-LIJ Health System, Great Neck, NY; 3 Ophthalmology, Manhattan Eye, Ear, and Throat Hospital, New York, NY. Purpose: Limbal relaxing incisions (LRI) are commonly used to reduce astigmatism. In recent years, the femtosecond laser has emerged as an alternative to manual incisional techniques due to greater perceived accuracy, precision, and safety. We performed a retrospective study to assess the keratometric results of femtosecond laser-assisted arcuate keratotomy in the treatment of corneal astigmatism. Methods: Preoperative and postoperative corneal topographic astigmatism measured with an Orbscan II (Bausch + Lomb) were retrospectively analyzed in consecutive patients who underwent fslri between March 2011 and June A single surgeon performed all procedures using an IntraLase Femtosecond Laser (Abbott Medical Optics Inc.) Incisional depth was set at 90% of central corneal thickness. Changes in topographic astigmatism were calculated and significance was determined by paired student s t-test. Regression methods were used to analyze the relationship between patient and surgical variables and changes in topographic astigmatism. Results: The study included 25 eyes of 20 patients (16 females, 4 males) with a mean age of 68.1 ± Mean preoperative astigmatism was 2.0 ± 1.1D ( D). Postoperatively, astigmatism was reduced by a mean of 0.8 ± 0.6D (p< ). Univariate linear regression analysis of astigmatic reduction as a function of arc length showed a moderate positive correlation R=0.69 (p<0.001). No significant correlation was found from separate univariate regression models of astigmatic reduction as a function of central corneal thickness (R=0.09, p=0.7) or diameter of LRI placement (R=0.01, p=0.9). A multivariable regression model of postoperative astigmatic reduction as a function of central corneal thickness, arc length, and diameter gave a positive correlation R=0.74 (p<0.001). In this model, arc length was a significant predictor of astigmatic reduction (p<0.0001) but corneal thickness (p=0.28) and diameter (p=0.07) were not significant. Conclusions: FSLRI was effective in reducing corneal topographic astigmatism although responses were variable. There was no association between reduction in topographic astigmatism and central corneal thickness or diameter of incision placement. The degree of astigmatic reduction was positively correlated with arc length but only moderately. Commercial Relationships: Phillip Rubin, None; Matthew Gorski, None; Carolyn Shih, None Program Number: 3920 Poster Board Number: D0125 Femtosecond and Nd:YAG laser Effects on a Presbyopia- Correcting Corneal Inlay and Adjacent Corneal Tissue Steve Linn 1, Robert Rivera 1, Yari Mitchell 2. 1 Hoopes Vision, Draper, UT; 2 AcuFocus, Irvine, CA. Purpose: To assess the influence of femtosecond laser-created anterior capsulotomy (AC), crystallline lens fragmentation (LF), and Nd:YAG posterior capsulotomy (PC) on corneal inlay and surrounding corneal tissue integrity. Methods: Prospective study of 20 post-mortem porcine eyes implanted with the KAMRA inlay (AcuFocus, Irvine, CA) into a femtosecond laser-created lamellar pocket. Post-implantation eyes were treated with either the Catalys femtosecond laser (AMO, Santa Ana, CA) (n=8), the LenSx femtosecond laser (Alcon, Ft. Worth, TX) (n=8) and the Ultra Q Nd:YAG laser (Ellex, Adelaide, Australia) (n=4). For the femtosecond laser treated eyes, each group was subdivided such that 2 eyes received a 5.0mm AC, 2 eyes received 3.0mm AC, 2 eyes received LF only, and the last 2 eyes received both LF and a 5.0mm AC. The PC treated eyes were subdivided into two groups of 2 eyes. PC was performed through the central aperture with the intention of not overlapping the inlay in 2 eyes. In the second group, PC was performed directly over the inlay. Changes to the inlay were evaluated in vivo and post-removal under the surgical microscope, at a slit-lamp and using SEM. Corneal histopathological exams were performed on the 4 PC eyes, 1 LF eye and 1 AC only eye.

6 Results: Catalys and LenSx treated eyes showed no evidence of damage to the inlays either upon visual inspection or SEM analysis. Visual inspection and SEM analysis for the group where the YAG laser shots were fired through the aperture showed no signs of damage or thermal changes to the inlay or surrounding corneal tissue. In the 2 eyes where the laser was fired over the annulus, the inlays appeared rough and malformed. Histopathology results for these 2 eyes revealed areas of liberated pigment granules on the anterior stroma. No evidence of thermal damage was noted. The other 4 corneas showed neither signs of liberated pigment nor any thermal damage to the cornea. Conclusions: Corneal inlay and tissue integrity remain unchanged after performing AC and LF with a femtosecond laser. It is possible to focus and fire laser shots at the posterior lens capsule without damaging the inlay or surrounding corneal tissue. Conversely, application of Nd:YAG laser either directly upon or close proximity to the inlay may cause significant liberation of pigment granules into the surrounding corneal stroma, and disrupts inlay integrity. Further evaluation is needed. Commercial Relationships: Steve Linn, AcuFocus (F); Robert Rivera, AcuFocus (C); Yari Mitchell, AcuFocus (E) Program Number: 3921 Poster Board Number: D0126 Efficacy of the VICTUS Femtosecond laser in correcting mild to moderate astigmatism during cataract surgery Eustace A. Penniecook, Rohit Adyanthaya, Nehal Patel, Victor H. Gonzalez. Valley Retina Institute, McAllen, TX. Purpose: To report the results of astigmatism correction using the Victus femtosecond laser arcuate incisions during cataract surgery Methods: Sixty one consecutive eyes with corneal astigmatism ranging from Diopters (D) to +4.0 D were treated with the Victus femtosecond laser to perform arcuate incisions immediately prior to phacoemulsification and crystalens implantation. Follow-up examinations were performed at 1 day, 1 week and 1 month Results: At 1 month follow-up, the mean refractive cylinder was reduced significantly from 1.34 D (Confidence Interval (CI) ) to 0.51D (CI ) (P<.001). The mean best corrected visual acuity improved significantly from 0.36 LogMAR (CI ) to 0.13 LogMAR (CI ) (P<0.001). No adverse effects occurred during procedures. Conclusions: The Victus femtosecond laser is safe and effective for the treatment of mild to moderate astigmatism during cataract surgery. Commercial Relationships: Eustace A. Penniecook, None; Rohit Adyanthaya, None; Nehal Patel, None; Victor H. Gonzalez, None Program Number: 3922 Poster Board Number: D0127 Laser Bridge AK: Novel Architecture for Femtosecond Laser Astigmatic Keratotomy Comparison and Validation of Patient- Specific Computational Modeling Anita Nevyas-Wallace 1, Harald P. Studer 2, Cynthia J. Roberts 3, 4. 1 Nevyas Eye Associates, Bala Cynwyd, PA; 2 Integrated Scientific Services, Port, Switzerland; 3 Ophthalmology, The Ohio State University, Columbus, OH; 4 Biomedical Engineering,, The Ohio State University, Columbus, OH. Purpose: Computational modeling of corneal incisions may help in identifying and developing incision architecture to maximize astigmatic effect while minimizing induction of higher order aberrations (HOA). This study validates a patient-specific computational model of a novel astigmatic keratotomy (AK) incision architecture, the Laser Bridge AK, and compares results which this model predicts for Laser Bridge AK with those which it predicts for AK incisions of uniform depth and thickness. Methods: Using finite element modeling, we simulated the novel architecture of Laser Bridge AK in a custom mathematical function which considered corneal incompressibility and nonlinearity, fiberinduced anisotropy, and inhomogeneity, taking into account realistic fiber distribution from x-ray scattering, and recognizing that corneal stroma is denser anteriorly than posteriorly. A 76 year old man underwent phaco/iol with AK o.s. Using a DuoTrak blade, a 9mm optical zone nasal AK was made 150 microns shallower centrally than at its ends. Incision morphology was measured via Optical Coherence Tomography. Pre-and post-op patient specific Galilei tomography were imported into Optimeyes software. The simulated incisions result was calculated with ABAQUS software. Postoperative results were compared to the simulated postoperative model for validation. Results: The patient s astigmatism was reduced from 1.75D against the rule to 0.25D with the rule. The simulated outcome was compared with the patient s postoperative Galilei corneal tomography. The simulated outcome showed a close match to the measured postoperative results. Compared with the model s predicted outcome for a traditional AK of uniform depth and thickness, the Laser Bridge AK was predicted to have substantially less induced higher order aberrations, as well as greater astigmatic effect. Conclusions: Patient-Specific Finite Element Modeling of the Laser Bridge AK was validated for the patient modeled. Laser Bridge FS laser AK incision architecture yielded optimal simulation results with less induction of HOA, yet greater astigmatism correction. Future studies include comparing different novel incision architectures. Commercial Relationships: Anita Nevyas-Wallace, Bausch + Lomb: (C), EyeIC (I), Patent application number 13/402,389 (P), Varitronics, Inc. (I); Harald P. Studer, ISS Integrated Scientific Services AG (E); Cynthia J. Roberts, Carl Zeiss Meditec:: (F), Oculus (C), Sooft Italia (R), Ziemer (C) Program Number: 3923 Poster Board Number: D0128 Effects of Surgical Experience on Corneal Wound Healing and Inflammatory Responses after Small Incision Lenticule Extraction (SMILE) Yu-Chi Liu 1, Ericia Pei Wen Teo 1, Nyein Chan Lwin 1, Gary Hin-Fai Yam 1, Jodhbir S. Mehta 2. 1 Ophthalmology, Singapore Eye Research Institute, Singapore, Singapore; 2 Singapore National Eye Centre, Singapore, Singapore. Purpose: To investigate the effect of surgical experience on the early corneal wound healing and inflammatory responses with different power of corrections of small incision lenticule extraction (SMILE). Methods: Twenty-four rabbits were divided into 3 groups and underwent -2.0 D, -4.0 D, and -8.0 D SMILE. One eye of each rabbit was performed by surgeon 1 (experienced), and the contralateral eye was performed by surgeon 2 (less experienced). Slit lamp examination, anterior segment optical coherence tomography (ASOCT), and in vivo confocal microscopy (IVCM) were performed at 1 day and 1 week postoperatively. The corneas were then subjected to immunofluorescent assays for CD11b, fibronectin and HSP47. Results: All corneas appeared clear throughout the follow-up period. There was a significant difference in the central corneal thickness evaluated by ASOCT between two surgeons at day 1 for -2.0 D treatment (P = 0.049). IVCM showed greater reflectivity after -8.0 D correction than -2.0 D correction at day 1 at the anterior, posterior, and extracted lenticule planes (surgeon 1: P = 0.004, P = 0.041, and P = 0.038; surgeon 2: P = 0.012, P = and P = 0.031). Different power of corrections did not significantly affect the amount

7 of CD11b, fibronectin, and HSP47 expression. Eyes performed by surgeon 2 exhibited more CD11b- and HSP47-positive cells at day 1 at the small vertical incision in -2.0 D group (P = and P = 0.042). The inflammatory and wound healing response subsided at week 1. Conclusions: The early inflammatory and wound healing response after SMILE was small, and was independent of power of corrections. In low myopic treatment, the disparity in surgeon experiences lead to different extent of inflammatory process. Commercial Relationships: Yu-Chi Liu, None; Ericia Pei Wen Teo, None; Nyein Chan Lwin, None; Gary Hin-Fai Yam, None; Jodhbir S. Mehta, None Support: This research was supported by the Singapore National Research Foundation under its Translational and Clinical Research (TCR) Programme (NMRC/TCR/1020 -SERI/2013) and administered by the Singapore Ministry of Health s National Medical Research Council. Program Number: 3924 Poster Board Number: D0129 Refractive Lenticule Extraction Complications Arturo J. Ramirez-Miranda, Alejandro Navas, Enrique O. Graue. Cornea and Refractive Surgery, Instituto de Oftalmologia Conde de Valenciana, Mexico City, Mexico. Purpose: To report the complications associated with refractive lenticule extraction (ReLEx) in its 2 modalities Femtosecond Lenticule Extraction (FLEx) and Small Incision Lenticule Extraction (SMILE) Methods: Retrospective review of consecutive clinical case series. Results: 94 eyes for the FLEx group and 160 for the SMILE group with mean follow-up around 36 months. 15 FLEx eyes presented surgical related complications (18.3%) including suction loss, lenticule failed to be created, decentered treatment, lenticule missdissection; and 43 SMILE eyes presented surgical complications (26.87%); including epithelial defect, as the most frequent,suction loss, lenticule miss-dissection, cap rupture, and lenticule rupture. Conclusions: While ReLEx complications can occur, most are solvable favorably, and not visually significant Commercial Relationships: Arturo J. Ramirez-Miranda, Carl Zeizz Meditec (C); Alejandro Navas, Alcon Mexico (F), Carl Zeiss Meditec (F); Enrique O. Graue, None Program Number: 3925 Poster Board Number: D0130 Comparison of biomechanical effects of small incision lenticule extraction and laser-assisted subepithelial keratomileusis Minjie Chen, jinhui dai. Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China. Purpose: To compare the biomechanical properties of the cornea after small-incision lenticule extraction (SMILE group) with those after laser-assisted subepithelial keratomileusis (LASEK group) by Ocular Response Analyser. Methods: In this prospective study, eyes that had mild to moderate myopic laser refractive surgery were categorized according to the type of flap creation: SMILE (n=31) or no flap creation LASEK (n=31). Corneal hysteresis (CH) and the corneal resistance factor (CRF) parameters were quantitatively assessed with the Ocular Response Analyzer preoperatively and 1, 3 months postoperatively. Multiple linear regression model analysis was then applied to adjust for selected covariates (the planned ablation depth, preoperative CH and CRF) to control for potentially confounding factors. Results: There were no significant differences in the preoperative manifest refraction spherical equivalent (MRSE), central corneal thickness (CCT), CH or CRF values between the LASEK group and the SMILE group (P>0.05). However, the planned ablation depth (AD) was 91.93±2.34um in the SMILE group which was significantly more than 80.37±2.78um in the LASEK group (P=0.0020). The decrease in CH and the CRF was statistically significant 1 and 3 month postoperatively compared with preoperatively in both groups (P<.0001). The LASEK group had significantly lower postoperative CH and CRF values than the SMILE group at both follow-ups after adjustment for the planned AD (P<0.1). Also, the changes in CH and CRF were less after SMILE than after LASEK in the 3-month postoperatively (P=0.002 and P=0.058, respectively). No significant correlations were found between the planned AD and changes in CH or CRF at any points in both groups. Conclusions: CH and CRF decreased after SMILE and LASEK. However, changes in the cornea s viscoelastic properties were less after SMILE than after LASEK. Consequently, SMILE should be able to correct higher levels of myopia. Commercial Relationships: Minjie Chen, None; jinhui dai, None Program Number: 3926 Poster Board Number: D0131 Accuracy of Astigmatism Correction with SMILE Timothy J. Archer 1, Dan Z. Reinstein 1, 2, Glenn I. Carp 1, Marine Gobbe 1. 1 Refractive Surgery, London Vision Clinic, London, United Kingdom; 2 Columbia University Medical Center, New York, NY. Purpose: To report the accuracy of refractive astigmatism correction using small incision lenticule extraction (SMILE). Methods: This was a retrospective analysis of 313 consecutive eyes with myopic astigmatism treated by SMILE using the VisuMax femtosecond laser (Carl Zeiss Meditec). Inclusion criteria were spherical equivalent (SEQ) treated up to D, refractive astigmatism treated of 0.75 D or more, and 3 month follow-up data available. A personalized nomogram was used for all treatments. Vector analysis was performed to evaluate the accuracy of the refractive astigmatism correction using the Alpins method. The analysis was then repeated for groups according to the axis of astigmatism (positive cylinder notation): with-the-rule (WTR, 60 to 120), oblique (30 to 60 and 120 to 150), and against-the-rule (ATR, 0 to 30 and 150 to 180). Results: Mean SEQ treated was -4.84±2.01 D (range: to D). Mean refractive astigmatism treated was 1.29±0.62 D (range: 0.75 to 4.25 D). Including all eyes, the arithmetic mean of the Difference Vector was 0.37 D (indicating this magnitude of refractive astigmatism remaining postoperatively). The vector mean of the Difference Vector was 0.12 D Ax 18. The geometric mean of the Correction Index (CI) was 1.08 (indicating a slight overcorrection), but the fan graph showed that the CI was >1 (overcorrected) for the majority of eyes with ATR astigmatism. The slope of the scatter plot of Target Induced Astigmatism (TIA) vs Surgically Induced Astigmatism (SIA) was 1.09 (indicating a slight overcorrection), compared to 0.86 when using the laser data entry as the TIA. The arithmetic mean of the Angle of Error was 0.28±8.19 and this was greater than 15 in only 6% of eyes (indicating no systematic rotational/cyclotorsion error). The slope of the TIA vs SIA scatter plot was 1.07 for the WTR group (n=175), 1.15 for the oblique group (n=48), and 1.32 for the ATR group (n=90) indicating a greater overcorrection moving from WTR to ATR astigmatism Conclusions: Use of a personalized nomogram improved the accuracy of SMILE astigmatism correction. This may be further improved by using a continuous function according to the axis of the astigmatism.

8 Commercial Relationships: Timothy J. Archer, None; Dan Z. Reinstein, Carl Zeiss Meditec (C); Glenn I. Carp, None; Marine Gobbe, None Program Number: 3927 Poster Board Number: D0132 Optical Zone Centration Comparison between SMILE and LASIK Marine Gobbe 1, Dan Z. Reinstein 1, 2, Glenn I. Carp 1, 2, Louis Gobbe 1, Timothy J. Archer 1. 1 Refractive Surgery, London Vision Clinic, London, United Kingdom; 2 Columbia University Medical Center, New York, NY. Purpose: To compare the optical zone centration between myopic eyes treated with small incision lenticule extraction (SMILE) and myopic eyes treated with LASIK. Methods: This was a retrospective analysis of 100 consecutive SMILE eyes of 100 patients and a matched group of 100 LASIK eyes of 100 patients. All SMILE treatments were performed using the VisuMax 500 khz femtosecond laser and all LASIK treatments were performed with VisuMax and MEL 90 excimer laser. Both SMILE and LASIK treatments were centred on the coaxially sighted corneal light reflex. Inclusion criteria were preoperative spherical equivalent (SEQ) between D and D, CDVA 20/25 or better and 3 month Atlas topography data available. A difference map of the tangential curvature was generated for each eye using the pre-operative and 3 months post-operative maps. A grid and a set of concentric circles were superimposed on the difference map to locate the centre of the optical zone. The x and y co-ordinates of centration offset between the center of the optical zone and the corneal vertex were measured to the nearest 0.05 mm. Results: The mean centration offset was 0.20 ± 0.11 mm for the SMILE group and 0.18 ± 0.11 mm for the LASIK group, with no statistically significant difference between groups (p<0.01). In the SMILE group, the optical zone was centred within 0.1 mm of the corneal vertex in 17% of eyes, within 0.2mm in 55%, within 0.3 mm in 81%, and within 0.4 mm in 96% of eyes. In the LASIK group, the optical zone was centred within 0.1 mm of the corneal vertex in 24% of eyes, within 0.2 mm in 62%, within 0.3 mm in 92%, and within 0.4 mm in 98% of eyes. There was no systematic directional decentration in either group. Conclusions: Although no eye tracker was used during the SMILE procedure, the optical zone was equally well centred compared with LASIK. Commercial Relationships: Marine Gobbe, None; Dan Z. Reinstein, Carl Zeiss Meditec (C); Glenn I. Carp, None; Louis Gobbe, None; Timothy J. Archer, None Program Number: 3928 Poster Board Number: D0133 Preliminary evaluation of hyperopic SMILE in amblyopic eyes Dan Z. Reinstein 1, 2, Kishore Pradhan 3, Glenn I. Carp 1, Timothy J. Archer 1, Marine Gobbe 1, Raynan Khan 1. 1 London Vision Clinic, London, United Kingdom; 2 Columbia University Medical Center, New York, NY; 3 Refractive Surgery Unit, Tilganga Institute of Ophthalmology, Kathmandu, Nepal. Purpose: To evaluate optical quality and centration outcome measures of small incision lenticule extraction (SMILE) for hyperopia. Methods: This was a prospective ethical committee approved study for eyes with hyperopic astigmatism treated by SMILE using the VisuMax femtosecond laser (Carl Zeiss Meditec). Study inclusion criteria were a maximum intended sphere up to +7 D with astigmatism up to 6 D, age 21 years, CDVA 20/100 or worse. Optical zone was centered on the corneal vertex and fixed at 6.3 mm with a 2 mm transition zone, 30 μm minimum lenticule thickness, and 120 μm cap thickness. Retinoscopic refraction and Atlas topography were obtained before and 1 month after surgery. Twenty eyes were included and 1 month data were available in 11 eyes at the time of writing. Refractive predictability, optical zone centration, achieved optical zone diameter (assessed by tangential curvature difference maps to the mid-peripheral power inflection point), and change in corneal spherical aberration (6 mm) were analyzed. MEL80 corneal vertex centered LASIK eyes matched for sphere and cylinder (±0.50 D) were randomly mined from our database to make 2 control groups: optical zone 6.5 mm or 7 mm (both transition 2 mm). Results: Mean SEQ was +4.68±1.30 D (+3.00 to D). Mean refractive astigmatism was 1.09±0.65 D (0.50 to 2.75 D). Mean postop SEQ was +0.10±0.91 D (-1.16 to D); 27% ±0.50 D and 82% ±1.00 D. Mean spherical aberration change was μm in the 6.3 mm SMILE group, found to be equivalent to the 7 mm LASIK group (-0.47 μm, p=0.916), but less than the 6.5 mm LASIK group (-0.79 μm, p=0.002). Mean optical zone offset was equal for all groups (p>0.73); 0.30±0.18 mm in the 6.3 mm SMILE group, 0.34±0.26 mm in the 7 mm LASIK group, and 0.29±0.15 mm in the 6.5 mm LASIK group. Mean achieved optical zone diameter was 5.55±0.35 mm in the 6.3 mm SMILE group; larger than the 6.5 mm LASIK group (4.65±0.18 mm, p<0.001) and the 7 mm LASIK group (4.93±0.32 mm, p<0.001). Conclusions: Optical zone centration was equivalent between vertex centered hyperopic SMILE and LASIK. Less spherical aberration was induced by 6.3 mm SMILE than 6.5 mm LASIK and was equivalent to 7 mm LASIK. Achieved topographic optical zone diameter was larger for 6.3 mm SMILE than 6.5 and 7 mm LASIK. Refraction change by retinoscopy appeared relatively accurate although longer term sighted eye studies will be required to refine nomograms and balance these with observed regression. Commercial Relationships: Dan Z. Reinstein, Carl Zeiss Meditec (C); Kishore Pradhan, None; Glenn I. Carp, None; Timothy J. Archer, None; Marine Gobbe, None; Raynan Khan, None Clinical Trial: NCT Program Number: 3929 Poster Board Number: D0134 Small Incision Lenticule Extraction Performed by Residents: Experience and Safety Andrew G. Olivo-Payne, Erick Hernandez-Bogantes, Arturo J. Ramirez-Miranda, Alejandro Navas, Enrique O. Graue. Cornea and Refractive Surgery, Instituto de Oftalmologia Conde de Valenciana, Mexico City, Mexico. Purpose: To describe the outcomes of small incision lenticule extraction (SMILE) performed by residents. Methods: A retrospective, study of 150 eyes of 86 patients with SMILE between May 2012 and April 2014 in one refractive referral center where included. Preoperative and postoperative uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), spherical equivalent (SE), keratometry, follow-up and complications were analyzed. Results: A total of 86 patients (150 eyes) with a mean age of 29.6 years old. The mean preoperative SE was / At month six, 81.8% of the patients had an UDVA of 20/25 or better and 93,7% achieved a CDVA of 20/25 or better. Adverse events were encountered in 32 patients (21.3)% being epithelial defect the most common. No UDVA loss was documented. None of the patients required a second intervention.

9 Conclusions: SMILE performed by residents is an effective and safe procedure with a minor learning curve. Commercial Relationships: Andrew G. Olivo-Payne, None; Erick Hernandez-Bogantes, None; Arturo J. Ramirez-Miranda, Carl Zeiss Meditec (C); Alejandro Navas, Alcon Laboratories (C), Carl Zeiss Meditec (C); Enrique O. Graue, None Program Number: 3930 Poster Board Number: D0135 Photorefractive keratectomy for residual refractive error in pseudophakic patients Lisa Chen, Edward E. Manche. Byers Eye Institute at Stanford, Palo Alto, CA. Purpose: To evaluate the outcomes of photorefractive keratectomy (PRK) for residual refractive error in pseudophakic eyes. Methods: In this retrospective case series, nine eyes of eight pseudophakic patients underwent wavefront-guided PRK surgery for residual refractive error. Safety, efficacy, and wavefront outcomes were evaluated. Results: This is an ongoing study. Results for the eight eyes with at least three months of follow-up are presented below. These data will be updated prior to the meeting. Three months after PRK, 75% (n=6) of eyes had an uncorrected distance visual acuity (UDVA) of 20/40 or better and 25% (n=2) had an UDVA of 20/25 or better. All eyes achieved an UDVA of 20/60 or better. Three eyes gained one or more lines of best-corrected distance visual acuity (CDVA). No eyes lost any lines of CDVA. 87.5% (n=7) of eyes were within +/-1.00 diopter (D) of emmetropia, and 87.5% (n=7) of eyes were within +/-1.00 D cylinder. The average spherical equivalent went from (range -2.5 to , standard deviation (SD) 1.045) preoperatively to (-0.75 to -0.13, SD 0.25) postoperatively. There was a similar decrease in average cylinder from 1.56 ( , SD 1.14) preoperatively to 0.69 (0-1.75, SD 0.5) postoperatively. Wavefront analyses revealed an overall reduction in total higher-order aberrations from a mean preoperative RMS error of 0.37 ( , SD 0.17) to 0.26 ( , SD 0.16) postoperatively. Average coma, trefoil, and spherical aberration were also reduced from preoperative values of 0.19 ( , SD 0.13), 0.21 ( , SD 0.15), and 0.06 (-0.16 to 0.22, SD 0.11) to postoperative values of 0.14 ( , SD 0.16), 0.11 ( , SD 0.08), 0.01 (-0.11 to 0.17, SD 0.09), respectively. There were no intraoperative or postoperative complications. No eyes developed corneal haze postoperatively. Conclusions: Wavefront-guided PRK was safe and effective in the treatment of residual refractive error in pseudophakic eyes. Commercial Relationships: Lisa Chen, None; Edward E. Manche, Best Doctors (C), Calhoun Vision, Inc. (I), Krypton Vision Inc. (I), Oculeve Inc. (C), Refresh Innovations, Inc. (I), Seros Medical, LLC (I), Veralas, Inc. (I) Program Number: 3931 Poster Board Number: D0136 The Aldehyde Trap NS2 Mitigates Dense Haze in a Rabbit Model of Photorefractive Keratectomy Daniel J. Gibson 1, Kenneth J. Mandell 2, Scott L. Young 2, Todd C. Brady 2. 1 University of Florida, Gainesville, FL; 2 Aldeyra Therapeutics, Lexington, MA. Purpose: To test whether the anti-inflammatory and anti-fibrotic effects of an aldehyde trap, 2-(3-amino-6-chloroquinolin-2-yl)- propan-2-ol (NS2), reduce corneal haze in a rabbit model of photorefractive keratectomy (PRK). Methods: All of the animals used herein were treated in a manner consistent with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. New Zealand White Rabbits corneas (n=18 eyes per group) were treated with one drop 0.5% NS2 or vehicle bilaterally QID for 3 days prior to surgery. Corneas from both eyes were ablated using an excimer laser with a diameter of 6.0mm and depth of 150μm to simulate a PRK procedure. Following induction of the PRK model, the eyes continued to receive either NS2 or vehicle QID for 5 days post-surgery. The wound closure rate, corneal edema, clinical grading of conjunctival irritation, & the progression of haze formation were then measured and compared at Days 4, 7, 10, & 14. Results: There were no significant differences in the closure rate, edema, or conjunctival irritation (chemosis & injection) at any time points. At the onset of haze formation (Day 4) there was no significant difference in haze between the NS2 and vehicle groups. However, on days 7, 10, & 14, corneal haze scores were significantly lower in the NS2-treated group relative to vehicle (p=0.011, p=0.014, & p=0.043). NS2 treatment precluded the treated corneas from reaching levels of haze associated with clinical grades of 3 or 4, whereas about 16% of the vehicle-treated corneas had clinical grades of 3 or 4. Conclusions: The aldehyde trap NS2 appears to reduce corneal inflammation in a rabbit model of PRK. Additional analyses are now being conducted to verify the results biochemically and histologically. The data suggest that NS2 has potential to be a novel therapy for PRK and other ocular diseases characterized by inflammation and fibrosis. Commercial Relationships: Daniel J. Gibson, Aldeyra Therapeutics, Lexington, MA, United States (F); Kenneth J. Mandell, Aldeyra Therapeutics, Lexington, MA, United States (C); Scott L. Young, Aldeyra Therapeutics (E); Todd C. Brady, Aldeyra Therapeutics, Lexington, MA, United States (E) Support: Grant from Aldeyra Therapeutics, Lexington, MA, United States Program Number: 3932 Poster Board Number: D0137 Retrospective Assessment of the Routine Use of Loteprednol Etabonate Gel 0.5% Following LASIK and PRK Surgery Clifford Salinger 1, Michael Gordon 2, Mitchell Jackson 3, Eric D. Donnenfeld 4. 1 VIP Laser Eye Center, Palm Beach Garden, FL; 2 Gordon-Weiss-Schanzlin Vision Institute, San Diego, CA; 3 Jacksoneye, Lake Villa, IL; 4 Ophthalmic Consultants of Long Island, Garden City, NY. Purpose: To assess real world experience using loteprednol etabonate ophthalmic gel, 0.5% (LE gel) for postoperative pain and inflammation following laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) surgery. Methods: This was a retrospective chart review conducted at multiple centers in the United States. Cases from patients aged 18 years and above were eligible for inclusion. Data were collected from cases of routine LASIK or PRK surgery in which LE gel was used postoperatively as the clinician s routine standard of care and in which patients were followed-up for up to 6 months. Data evaluated included refractive characteristics, intraocular pressure (IOP) measurements, LE gel dosing regimen, adverse events (AEs) and early discontinuations. The primary outcomes of interest included IOP changes, other AEs, and reasons for any early treatment discontinuation. Results: This analysis, representing data from 4 clinical sites to date, included 237 eyes (98, LASIK; 139, PRK) from 121 patients (mean age: LASIK, 35.2 years; PRK, 34.1 years). The most common post-operative dosing regimens for LE gel were QID for one week in LASIK patients, and a 4-week tapered dosing regimen (QID,

10 TID, BID, QD, each for 1 week) in PRK patients. Depending on the site, postoperative treatment with LE gel was initiated either on the surgical day or first post-surgical day. Most patients received concurrent treatment with topical NSAIDs (primarily bromfenac or nepafenac) and antibacterials (besifloxacin or moxifloxacin). Mean (± SD) IOP decreased from 15.2 ± 2.3 mm Hg (range = 9-14 mm Hg) preoperatively to 14.1 ± 2.5 mm Hg (range, 9-21 mm Hg) in the LASIK cohort (P=0.0021) and from 14.8 ± 2.9 mm Hg (range, 7-26 mm Hg) preoperatively to 14.2 ± 3.9 mm Hg (range, 8-25 mm Hg) in the PRK cohort (P=0.2390). There were no IOP elevations 10 mm Hg or IOP measurements >25 mm Hg at any postoperative visit. Other than persistent corneal haze in a PRK patient prompting a temporary substitution of prednisolone for LE gel, there were no AEs attributed to LE gel in either cohort or early discontinuation of LE gel therapy. Most patients had a final visual acuity of 20/20 or better. Conclusions: Based on real world experience, LE gel appears to have a high level of safety and tolerability when used for the management of postoperative pain and inflammation following LASIK and PRK surgery. Commercial Relationships: Clifford Salinger, Bausch & Lomb (C); Michael Gordon, None; Mitchell Jackson, Bausch & Lomb (C); Eric D. Donnenfeld, None Program Number: 3933 Poster Board Number: D0138 Outcomes of pediatric photorefractive keratectomy for correction of pseudophakic myopia Lawrence Tychsen 1, Nicholas Faron 2, James Hoekel 2. 1 Ophthal and Neurobio-Childrens Hosp, Washington Univ School of Medicine, St Louis, MO; 2 Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO. Purpose: Children who have implantation of a standard, posterior chamber IOL at younger ages commonly develop pseudophakic myopia as axial length increases with growth. As an alternative to IOL exchange surgery, we report here outcomes of PRK in children who had pseudophakic myopia and difficulty wearing spectacles or contact lenses. Methods: Clinical outcome data were collated prospectively in 7 children (8 eyes). Each child was amblyopic, and had undergone cataract surgery with implantation of a pc IOL. Mean IOL power was 20.83D. The mean age at IOL implantation was 5.76 yrs (range 1-11) and PRK 12.4 yrs (range 7-19). The mean follow-up from the IOL implantation was 11.7yrs. Results: Pseudophakic refractive error prior to PRK averaged -5.04D (range -2 to -8.25D). 2 years after laser treatment, each child was within ±0.5D of target value. Refractive spherical regression averaged -0.10D/yr. Uncorrected visual acuity improved from an average logmar 0.9 (20/159) to 0.17 (20/30); best corrected visual acuity improved an average of 0.22 logmar. 5/7 children treated had a gain in at least one level of binocular fusion; the remaining 2 remained at their preoperative level. No patient developed haze following PRK. Conclusions: Our preliminary results show excimer laser PRK is an effective means for correcting refractive error and improving uncorrected visual acuity in pseudophakic amblyopic children. Commercial Relationships: Lawrence Tychsen, None; Nicholas Faron, None; James Hoekel, None Program Number: 3934 Poster Board Number: D0139 Impact of myopic refractive surgery on the accommodative vergence cross coupling Christophe Panthier 1, 2, Jean Claude Rigal-Sastourné 2, 3, Corinne Roumes 4, Pascaline Neveu 4. 1 Hopital Hôtel Dieu, Paris, France; 2 Hôpital d Instruction des Armées Percy, Clamart, France; 3 Hôpital Bégin, Saint Mandé, France; 4 Institut de Recherche Biomédicales des Armées, Brétigny sur Orge, France. Purpose: Myopic refractive surgery is one of the most performed surgical procedures worldwide. The consequences of this surgery on the oculomotor system balance are poorly known. The purpose of this study was to explore the impact of myopic refractive surgery on the accommodative-vergence cross-coupling. Methods: This prospective study included suitable patients for refractive surgery, aged from 18 to 36 years and with myopia between -3 to -8 diopters (D) of spherical equivalent. Strabismus, eye diseases or drugs that may interfere with the oculomotor system, were exclusion criteria. Patients were divided into two groups: control or treated. The surgical technique chosen for this study was the bilateral LASIK (Laser Assisted In Situ Keratomileusis) associate with femtolaser corneal flap. Four oculomotor parameters were assessed: tonic vergence (TV), tonic accommodation (TA), accommodative vergence (response AC/A ratio) and vergence accommodation (CA/C ratio). They were assessed before the surgery (J0) and after one (M1) and three months (M3) after surgery. Measurements were conducted using a- haploscope-optometer. A correlation between changes in the parameters and symptoms of visual fatigue was investigated using a questionnaire. Results: 40 patients were included in the study (15 in the control group and 25 in the treated group). The mean age of participants was ± 4 years. The initial average refractive error was ± 1.11 D. There was one lost subject in the treated group. Groups were similar at baseline for all the clinical features and the oculomotor parameters studied. AC/A ratio was higher for eyeglass wearers than among contact lens wearers at J0 (t-test, df = 35, p = 0.04). There was no change of the oculomotor system in the control group between J0, M1 and M3. At M1, the TA increased (F(1, 18)=8.763; p<0.001). The AC/A ratio decreased (F (1, 21)=26.150; p<0.001) one month after surgery. The variation of the AC/A ratio has been correlated with symptoms of asthenopia one month after surgery (R2=0.79; p<0.001). Conclusions: Myopic refractive surgery has affected the oculomotor system balance by deleting the ametropia and its correction. Changes were an increase of the TA and a decrease of the AC/A ratio whose intensity was correlated with the appearance of subjective symptoms of visual fatigue. Surgical emmetropization resulted in a transient oculomotor emmetropization. Commercial Relationships: Christophe Panthier, None; Jean Claude Rigal-Sastourné, None; Corinne Roumes, None; Pascaline Neveu, None Support: support by the DCSSA Direction Centrale du Service de Santé des Armées Clinical Trial: B-32 RS

11 Program Number: 3935 Poster Board Number: D0140 Assessment of corneal changes after LASIK myopia treatment using OCT and topography Li Chen, Eugenia Thomas, Dimitri Chernyak. Abbott Medical Optics, Milpitas, CA. Purpose: To investigate the corneal changes of postoperative LASIK eyes after myopia treatments using corneal optical coherence tomography (OCT) images and corneal topography images. Methods: This study included 58 eyes with preoperative MRSE ranging from -4.00D to D. All eyes were treated for moderate to high myopia with LASIK treatments using 8mm ablation zone with 6mm optical zone. Preoperative and postoperative images were taken from each eye with corneal OCT by RTVue CAM (Optovue Inc.), and corneal topography by idesign Advanced WaveScan Studio (AMO Development, LLC). Preoperative and the 3-month postoperative corneal measurements were analyzed to assess the corneal changes after LASIK treatment. Wavefronts, corneal pachymetry maps and corneal surface profiles were evaluated in comparison to the desired treatments within 6mm optical zone. Corneal power and corneal curvature values were extracted from the central 3mm zone. Results: The ablation shapes obtained from the 3-month postoperative measurements were in close agreement with the targeted ablation shapes derived from preoperative wavefront exams. Compared to the preoperative corneal measurements, postoperative changes of corneal anterior surface were also consistent with the myopia treatments including decreased corneal power (P<0.001) and increased corneal curvatures (P<0.001). There was excellent correlation between the anterior topography difference maps from idesign and pachymetric changes obtained from the OCT. No significant difference in the posterior corneal surface was observed between preoperative and postoperative measurements of mean corneal power (P=0.566) and mean curvature radius (P=0.473). On average, the 3-month postoperative corneal epithelium became thicker with increased 3 microns central epithelial thickness (P<0.001). Conclusions: Corneal OCT images and corneal topography images from preoperative and postoperative measurements provide very useful information to evaluate corneal changes after LASIK treatment. This study shows that there is no significant change in the posterior power and posterior curvature radius after LASIK myopia treatment. After LASIK procedure, mean corneal epithelial thickness increased by 3 microns, which was statistically significant. Furthermore, the study shows close agreement between the two instruments on the measurement of the achieved ablation profile as well as agreement with programmed correction. Commercial Relationships: Li Chen, Abbott Medical Optics (E); Eugenia Thomas, Abbott Medical Optics (E); Dimitri Chernyak, Abbott Medical Optics (E) Clinical Trial: NCT Program Number: 3936 Poster Board Number: D0141 Superficial corneal crosslinking during LASIK Isaak R. Fischinger 2, 1, Theo G Seiler 2, 1, Tobias Koller 3, Victor Derhartunian 1, Theo Seiler 1. 1 Ophthalmology, IROC, Zürich, Switzerland; 2 Opthalmology, Technische Universität München, München, Germany; 3 Ophthalmology, IROC, Zütich, Switzerland. Purpose: To determine the safety of superficial corneal crosslinking (SCXL) after LASIK Methods: In a prospective study, 78 eyes of 78 patients were treated with LASIK for myopia correction and followed for up to 1 year. All eyes had an ectasia risk score of 2 and more. After the standard LASIK (90mm-flap) a rapid CXL was performed in the interface (riboflavin 0.5% for 2 minutes, 9mW/cm 2 for 5 minutes). Additional to the standard follow up-examinations at 1 and 12 months post operatively at any appointment a corneal OCT-scan was performed. The incidence of complications was statistically compared to a group of eyes treated with standard LASIK and matched regarding age, gender and attempted refractive correction. Results: At 1 month after surgery, 5 eyes of the SCXL group had lost one line in BSCVA compared to 1 eye of the control group (p>0.05). All eyes had regained preoperative BSCVA at 1 year after surgery indicating a complication rate of less than 5%. Refractive success was identical in both groups. Early post-operative complications like erosions (15%) and DLK1 (38%) and DLK2 (5%) were significantly more frequent after SCXL. Conclusions: Based on 1 year-results, SCXL might be considered a safe adjunct to LASIK. Whether SCXL is capable to prevent iatrogenic keratectasia is not proven. Commercial Relationships: Isaak R. Fischinger, None; Theo G Seiler, None; Tobias Koller, None; Victor Derhartunian, None; Theo Seiler, Wavelight Alcon (C) Clinical Trial: 908 Program Number: 3937 Poster Board Number: D0142 Accelerated Epi-On Collagen Cross-linking for Keratoconus in Children Enrique O. Graue, Andrew G. Olivo-Payne, Erick Hernandez- Bogantes, Alexandra Abdala-Figuerola, Arturo J. Ramirez-Miranda, Alejandro Navas. Cornea/Enfermedades Externas, Instituto de Oftalmologia, Mexico, Mexico. Purpose: To evaluate the effectiveness and safety of accelerated corneal collagen cross-linking (CXL) in children with keratoconus Methods: Retrospcetive review of clinical records of patients <16 years of age with clinical and topographic diagnosis of keratoconus treated with accelerated transepithelial collagen cross-linking treated at the Insituto de Oftalmología Fundación Conde de Valenciana in Mexico City. Follow-up was done at day 1, week 1, 1, 3 6 and 12 months. Complete ophthalmic examination including subjective refraction and topography ( Sirius, CSO, Italy) were performed at each visit. Paired t test was used to compare the difference from baseline of evaluated parameters at each follow-up visit. The level of statistical significance was set at P < Results: Fourteen patients (23 eyes) were included in the study. The mean age was 13.7 years ±1.4 (range 11-16) with an overall male to female ratio of 3:1. Mean follow-up was months ±3.1 (range 9-16 months).preoperative uncorrected distance visual acuity was 0.92 ±0.45 LogMAR. Postoperative UDVA was measured at 0.75 ±0.40 LogMAR, with a statistically significant improvement of ±0.15 LogMAR (p=0.001) Preoperative BCVA was 0.26 ±0.30 LogMAR compared to postoperative BCVA: 0.15 ±0.15 LogMAR and had a statistically significant Improvement of ±0.26 LogMAR scale (p=0.029).preoperative mean keratometric (Km) readings were 53.63D ±5.84 and postoperative Km readings were 52.60D ±5.22D showing a significant Improvement of -1.02D ±0.79 D (p=0.029).preoperative pachymetry was registered at 433 microns ± 37 at 12 months pachymetry was 431 ± 43 microns which translates to a non-significant corneal thinning of 2 microns ± 17 (p=0.36) Conclusions: Preliminary results of accelerated CXL were encouraging, with no evidence of progression in over 95% of eyes over 12 months. Commercial Relationships: Enrique O. Graue, None; Andrew G. Olivo-Payne, None; Erick Hernandez-Bogantes, None; Alexandra

12 Abdala-Figuerola, None; Arturo J. Ramirez-Miranda, None; Alejandro Navas, None Program Number: 3938 Poster Board Number: D0143 Refractive, topographic and pachymetric outcomes after corneal Crosslinking in progressive keratoconus. Shameli Guzman Tapia, Cristina Pacheco Del Valle, Oscar Fernandez, Oscar Baca, Regina Velasco, Alejandro Babayan, Elisa D. Alegria. Cornea, Hospital de la Luz, Cuauhtemoc, Mexico. Purpose: To analyze the topographical, pachymetric, keratometric and refractive changes induced by Crosslinking in eyes with keratoconus, 3 year follow-up at Hospital de la Luz in Mexico City. Methods: A descriptive, retrospective, in 21 patients (23 eyes) with progressive keratoconus who underwent Crosslinking during September 2011 and Data were collected preoperatively, a month, three months, six months and one year study. The variables studied were age, gender, visual acuity without correction, spherical equivalent, topographic keratometry and corneal thickness. Results: Male predominated (66%), we obtain an average of 21 years old and an increased stage two of keratoconus (Amsler- Krumeich). The best corrected visual acuity modifies from 0.29 ± 0.30 preoperatively to 0.17 ± 0.1 after the first month of surgery. The spherical equivalent from ± 6.28D decreases to ± 1.94 diopters to the sixth postoperative month. The maximum preoperative keratometry topographic from ± to D at the third month. Preoperative central optical pachymetry from ± microns to ± micron after a year and the thinnest pachymetry from ± microns to ± microns after the year control. Conclusions: Significant keratometric, pachymetric, topographic and refractive changes are shown to arrest the progression of keratoconus in patients undergoing Crosslinking in a medium term. Commercial Relationships: Shameli Guzman Tapia, None; Cristina Pacheco Del Valle, None; Oscar Fernandez, None; Oscar Baca, None; Regina Velasco, None; Alejandro Babayan, None; Elisa D. Alegria, None Program Number: 3939 Poster Board Number: D0144 Femtosecond laser assisted keratopigmentation for presbyopia correction Vladimir G. Lemberg 1, Hong Fu 1, James E. Hill 1, 2. 1 Advanced R&D, Abbott Medical Optics Inc., Milpitas, CA; 2 R&D, Abbott Medical Optics Inc., Santa Ana, CA. Purpose: One of the presbyopia correction methods is to insert a ring-like inlay (KAMRA Inlay, AcuFocus, Inc.) into the corneal stroma of the non-dominant eye. The purpose of this work is to explore the concept of using femtosecond laser assisted keratopigmentation for presbyopia correction. In particular, we evaluate the ability of the ifs laser to create the intricate corneal features and the feasibility to produce a pigmented aperture in a femtosecond laser ring cut. This method of presbyopia correction is expected to eliminate foreign body sensation and the impact of inlay on nutrients flow. It enables precisely controllable aperture centration and eliminates potential corneal inlay displacement. Methods: Experimentally, we used the ifs laser (Abbott Medical Optics Inc.) to create the intracorneal ring cut in porcine corneas, then filled the channel with opaque ink. The ring cut was created at a depth of 200 microns in the cornea. The inner ring diameters tested were 1.0 and 1.5mm, respectively, and the outer ring diameters were 3, 4, and 5mm, respectively, and the laser pulse energy ranged from 0.3 to 1.5μJ. The diameter of the anterior side cut was 3.7mm, and the energy was 1.4μJ. The ring cut is injected with a biocompatible dye to create an aperture, which has been proven safe and durable in corneal tattooing. Four different dyes were tested. Two types of needles were tested for injecting the dye. Theoretically, we analyzed the blur and image quality as a function of defocus and pupil sizes. Results: The femtosecond laser produced complete ring cut on the porcine corneas. We injected the dye into the ring cut through the anterior side cut. In all samples the injected dye spread to cover the ring area and formed an aperture. We observed that the dye spreading resulted in a tendril type pattern at the inner and outer edges. The theoretical analysis shows that an up to 3 diopters depth of focus can be gained with reasonable aperture sizes. Conclusions: The intricate corneal features created by the ifs femtosecond laser enabled keratopigmentation for presbyopia correction. The keratopigmentation is expected to have several advantages over a ring-like inlay. Preliminary feasibility to produce a pigmented aperture with femtosecond laser ring cut is demonstrated. Further research is needed to address the reversibility of the keratopigmentation. Commercial Relationships: Vladimir G. Lemberg, Abbott Medical Optics (E); Hong Fu, Abbott Medical Optics (E); James E. Hill, Abbott Medical Optics (E) Program Number: 3940 Poster Board Number: D0145 The Effects of Implantation Depth on Outcomes Using a Corneal Shape Changing Inlay to Improve Near Vision in Presbyopic Emmetropes at One Year after Surgery Adam J. Roy 1, Roger F. Steinert 2, Randy Alexander 1, Keith Holliday 1, Alan J. Lang 1. 1 ReVision Optics, Inc, Lake Forest, CA; 2 Gavin Herbert Eye Institute, University of California, Irvine, CA. Purpose: To retrospectively investigate the effect of implantation depth in the cornea, with the Raindrop Near Vision Inlay*, on outcomes of presbyopic emmetropes at one year postoperative. *CAUTION: Investigational device. Limited by Federal (US) law to investigational use. Methods: 373 presbyopic emmetropes were implanted with the Raindrop corneal inlay in the non-dominant eye beneath a femtosecond corneal flap as part of a prospective, multicenter, US clinical trial. The meniscus shape of the inlay is designed to improve near vision by changing the curvature of the anterior cornea to progressively increase refractive power from the pupil center. The implantation depth was calculated by dividing the corneal flap thickness targeted with the laser by the preoperative central corneal pachymetry. Trace corneal haze (grade 1) was measured by slit lamp examination, uncorrected visual acuities with Optec 6500, and wavefront topography also evaluated the optical effect of the inlay. Multivariate statistics determined the effect of implantation depth on these visual outcomes one year after Raindrop implantation. Results: The incidence of trace haze is strongly associated with implantation depth (p < 0.001), with significantly lower incidence for deeper implantations. The proportion of trace haze at least once during the first year was (i) 50% (5/10) of patients for the corneal depth from 22.0% to 24.9%, (ii) 23% (19/82) of patients at 25.0% to 27.9% depth, (iii) 11% (20/187) of patients at 28.0% to 30.9% depth, and (iv) 3% (2/61) of patients at 31.0% to 34.0% depth. Topography demonstrated a slightly weaker inlay effect for the deeper implantations, but patients still obtained a similar, significant improvement in near and intermediate acuities across all depths. Conclusions: Surgeons should target their femtosecond flap at 33% corneal thickness to optimize the visual outcomes with the Raindrop Near Vision Inlay. At this implantation depth, central corneal haze is

13 minimized while still obtaining significant improvement in near and intermediate visual acuity for presbyopic emmetropes. Commercial Relationships: Adam J. Roy, ReVision Optics, Inc. (E); Roger F. Steinert, ReVision Optics, Inc. (C); Randy Alexander, ReVision Optics, Inc. (I); Keith Holliday, ReVision Optics, Inc. (E); Alan J. Lang, ReVision Optics, Inc. (E) Clinical Trial: NCT Program Number: 3941 Poster Board Number: D0146 Micro-Monovision LASIK as a treatment for presbyopia Alejandro Tamez, Jesus Lozano, Manuel De Alba, Julio C. Hernandez, Jorge E. Valdez. Ophthalmology, Tec Salud, San Pedro Garza Garcia, Mexico. Purpose: To investigate the efficacy and safety of LASIK monovision technique as a treatment for ametropia and presbyopia. Methods: A retrospective case series study that included 70 eyes of 35 ametropic and presbyobic patients that were treated with LASIK monovision in our Cornea and Refractive surgery service from January 2013 to February We evaluated the postoperative uncorrected binocular visual acuity: for distance and near. The target refraction was emetropia for the dominant eye and between to in the non-dominant eye. All surgeries where operated by the same two refractive surgeons, with the same equipment, technique and surgery conditions. Results: The average patient age was 50.9 years old (39-64), of which 60% were women. Refractive error: 26 with hyperopic astigmatism, 4 with simple hyperopia and 5 with myopic astigmatism. The Binocular distance visual acuity was 20/25 or better in 94% of patients and binocular near vision was J2 or better in 97% of patients. Mean follow-up of 4.4 months (1-12). Conclusions: LASIK Micro-Monovision technique has proven to be a well-tolerated, safe and effective way to treat ametropia and presbyopia. Commercial Relationships: Alejandro Tamez, None; Jesus Lozano, None; Manuel De Alba, None; Julio C. Hernandez, None; Jorge E. Valdez, None Program Number: 3942 Poster Board Number: D0147 Incidence of Microtome Complications of Corneal Refractive Surgery Orry Birdsong, Alexander Davis, Kevin Merkley. Ophthalmology, University of Texas Medical Branch, Galveston, TX. Purpose: Laser in situ Keratomileusis has been increasingly popular for the correction of refractive error in applicable patients. While many various studies have described and quantified the complications of LASIK with microkeratome use, few have looked in patient and instrumentation specific etiologies for these complications. In this retrospective observational study, we recognize common microkeratome complications with LASIK and identify potential etiologies and safeguards for these complications. Methods: LASIK procedure cases performed a private LASIK center were retrospectively reviewed identifying complications over a time frame of 27 months between complications were then identified and categorized. Patient demographics, microkeratome depth and ring size, average corneal thickness, corneal cylinder, best corrected visual acuity pre and post treatment, pachymetry, flap thickness, white to white measurement, and refractive error spherical equivalent were reviewed. Cases were then further reclassified by subsequent retreatment methods to evaluate resolution after complications occurred and correlations determined based on findings. Results: Of the 26 complications identified, 4 button hole flaps, 5 non-button hole flaps, 2 decentered flaps, 3 free caps, 4 irregular flaps, and 8 partial flaps were identified. Average age of patients was years and 38% of cases were female and 62% male. In 96% of noted complications, the 120um microkeratome was used, and in 73% of noted complications, the 9.5mm ring size was used. Average K thickness was D. Average corneal cylinder was Average pachymetry measured by ultrasound and Orbscan were and respectively. Average white to white measurement was 11.88mm. Average refractive error spherical equivalent was D. 65% patients with complication underwent retreatment. Of these patients, 23% underwent recutting and the remaining 77% underwent PRK. Conclusions: Higher rates of complication were noted with the 120um microkeratome depth and 9.5mm ring size. Our results also show that complications arise more in myopic patients. Although microkeratome complication rates are low overall in the number of reviewed cases, continued prospective confirmation of these risk factors can allow for careful consideration of these parameters when performing LASIK procedures. Commercial Relationships: Orry Birdsong, None; Alexander Davis, None; Kevin Merkley, None Program Number: 3943 Poster Board Number: D0148 Bioptics - pursuing emmetropia in patients with high myopic astigmatism Kraig S. Bower 1, Denise S. Ryan 3, Rose K. Sia 3, Paul Houghtaling 1, Scott McClellan 2, Bruce Rivers 3. 1 Ophthalmology, Wilmer Eye Institute, Lutherville, MD; 2 Ophthalmology, Kimbrough Ambulatory Care Center, Fort Meade, MD; 3 Warfighter Refractive Eye Surgery Program and Research Center, Fort Belvoir, VA. Purpose: To analyze refractive outcomes of highly myopic astigmats an average of 566 days post-operatively after first undergoing phakic intraocular lens implantation for myopia followed three months later by WFG PRK or LASIK. Methods: Five women and two men (14 eyes) with a mean age 28.3 years (range 21-45), and an average spherical equivalent refraction of diopters (D) ± 1.85 D and average cylinder of 2.80 D ± 0.76 D underwent dual refractive procedures. First an implantable collamer lens was inserted through a self sealing corneal incision. Three months or more post-implantation, after documenting refractive stability, four patients underwent WFG (VISX CustomVue STAR S4 IR) PRK (three with mitomycin-c) and three underwent WFG LASIK. Uncorrected distance visual acuities (UDVA), manifest refraction (MR), corrected distance visual acuities (UDVA), corneal topography, corneal pachymetry, wavefront higher order aberrations (HOA), and endothelial cell densities (ECD) were determined preoperatively and postoperatively. Results: Final visual outcomes [mean 566 days (range days)], 14/14 eyes (100%) achieved UDVA of 20/20 or better and 8/14 (57%) achieved UDVA of 20/15 or better. No eye lost more than one line of corrected distance visual acuity (CDVA). Regression analysis showed strong correlation between attempted and achieved refractive correction (R 2 =0.98). Manifest Refractive Spherical Equivalent (MRSE) were within 0.50 D of emmetropia in 86% of eyes and were within 1.00 D of emmetropia in 100% of eyes. Postoperative refractive cylinder was less than 0.50 D in 93% and less than 1.00 D in 100% of treated eyes. Regression analysis showed a strong correlation between target induced astigmatism and surgically induced astigmatism (R 2 =0.89). Between six months and the final postoperative visit, refractive stability was achieved in 83%

14 of eyes. Pre and postoperative keratometry, pachymetry, HOA, and ECD results are shown in Table 1. Conclusions: Refractive correction using bioptics enabled effective treatment of high myopia with astigmatism with excellent predictability and few adverse effects in the intermediate term. This approach can be appropriate in settings where laser vision correction as a sole procedure is inadvisable and where a toric phakic IOL is not available. Commercial Relationships: Kraig S. Bower, None; Denise S. Ryan, None; Rose K. Sia, None; Paul Houghtaling, None; Scott McClellan, None; Bruce Rivers, None Program Number: 3944 Poster Board Number: D0149 Rifle marksmanship performance following wavefront-guided (WFG) vs. wavefront-optimized (WFO) refractive surgeries Denise S. Ryan 2, Rose K. Sia 2, Richard Stutzman 1, Joseph F. Pasternak 1, Lamarr Peppers 2, Jennifer B. Eaddy 2, Lorie A. Logan 2, Bruce Rivers 2, Kraig S. Bower 3. 1 Ophthalmology, Walter Reed National Military Medical Center, Bethesda, MD; 2 Warfighter Refractive Eye Surgery Program and Research Center, Fort Belvoir, VA; 3 Ophthalmology, Wilmer Eye Institute, Baltimore, MD. Purpose: To compare rifle marksmanship performance after WFG vs. WFO refractive surgeries. Methods: In this prospective study, 55 myopic U.S. military service members with mean age 30.0 ±6.7 years and mean manifest refractive spherical equivalent ±1.43 diopters undergoing either PRK or LASIK were randomized to receive either WFG (VISX CustomVue STAR S4 IR) or WFO (Wavelight Allegretto Wave EyeQ excimer laser systems) treatment. Marksmanship performance was evaluated preoperatively and at 6 weeks (W) and 6 months (M) postoperatively. Participants were asked to fire an M16-A4 rifle under three conditions: iron sight under low light (approximately 1 cd/m 2 ); night vision goggle (NVG); and forward-looking infrared (FLIR) thermal sight under starlight (approximately cd/m 2 ). Pre- and postoperative firing range scores were compared between treatment groups at each time point. Four groups (WFG PRK, n=13; WFG LASIK, n=14; WFO PRK, n=14; and WFO LASIK, n=14) were compared using the Kruskal-Wallis test. For multiple comparison, a Bonferroni adjusted p-value<0.02 was considered statistically significant. Results: There was no significant difference in firing scores among the treatment groups preoperatively except when using FLIR thermal sight (P=0.01). Post-hoc analysis revealed firing scores when using FLIR thermal sight in WFG PRK group was significantly higher than that in WFG LASIK group (P=0.017), preoperatively. At 6W postoperatively, there was a significant difference in firing scores using iron sight among the groups (P<0.01) but not in firing scores using NVG and FLIR thermal sight. Further analysis revealed firing scores using iron sight in WFG PRK and WFO PRK groups were significantly higher than that in WFG LASIK group (P=0.018 and P=0.015, respectively) 6W postoperatively. The firing scores using iron sight, NVG and FLIR were comparable for all groups at 6M postoperatively. Conclusions: WFG and WFO PRK may offer a short-term advantage over WFG LASIK in low light firing performance. Overall, using WFG or WFO treatment in either PRK or LASIK results in comparable rifle marksmanship performance in U.S. soldiers after surgery. Vision enhancers, like NVG and FLIR thermal sight, in rifle marksmanship performance are not hampered by refractive surgery. Commercial Relationships: Denise S. Ryan, None; Rose K. Sia, None; Richard Stutzman, None; Joseph F. Pasternak, None; Lamarr Peppers, None; Jennifer B. Eaddy, None; Lorie A. Logan, None; Bruce Rivers, None; Kraig S. Bower, None Support: Funded by USAMRAA Award W81XWH Clinical Trial: NCT Program Number: 3945 Poster Board Number: D0150 Visual performance in military target identification after wavefront-guided (WFG) and wavefront optimized (WFO) PRK and LASIK Bruce Rivers 1, Denise S. Ryan 1, Rose K. Sia 1, Tana Maurer 2, Christopher Howell 2, Richard Stutzman 3, Joseph F. Pasternak 3, Kraig S. Bower 4. 1 Warfighter Refractive Eye Surgery Program and Research Center, Fort Belvoir, VA; 2 Night Vision and Electronic Sensors Directorate, Fort Belvoir, VA; 3 Ophthalmology, Walter Reed National Military Medical Center, Bethesda, VA; 4 Ophthalmology, Wilmer Eye Institute, Baltimore, MD. Purpose: To assess visual performance when identifying targets of military interest after WFG and WFO photorefractive keratectomy (PRK) and LASIK. Methods: In this prospective randomized study, 53 military service members aged 29.9±5.5 years with myopia or myopic astigmatism (mean manifest spherical equivalent -3.78±1.42 diopters) electing to undergo either PRK or LASIK were randomized to receive either WFG (VISX CustomVue STAR S4 IR) or WFO (Wavelight Allegretto Wave EyeQ) treatment. Performance on military tasks was determined preoperatively with correction as well as 6 weeks and 6 months postoperatively without correction. In separate computer-based experiments, participants were asked to 1) identify static combat vehicle targets and 2) identify dynamic combatants and noncombants targets. Change in probability of identification (PID) was compared among the treatment groups using repeated measures analysis of variance. A P<0.05 was considered statistically significant. Results: In identifying static combat vehicle targets, there was no significant difference in PID between WFG versus WFO groups (P=0.41) as well as between PRK versus LASIK groups (P=0.14). In identifying dynamic combatants/noncombatant targets, there was also no significant difference in PID between WFG versus WFO groups (P=0.82) and between PRK versus LASIK groups (P=0.41).

15 The change in PID of static and dynamic targets over time was not statistically significant overall among the 4 treatment groups (WFG PRK, WFG LASIK, WFO PRK and WFO LASIK; P=0.68 and P=0.72, respectively). Conclusions: Treatment using WFG or WFO in either PRK or LASIK may offer comparable benefits to myopic military service members in terms of visual performance such as identifying military relevant static and dynamic targets. Commercial Relationships: Bruce Rivers, None; Denise S. Ryan, None; Rose K. Sia, None; Tana Maurer, None; Christopher Howell, None; Richard Stutzman, None; Joseph F. Pasternak, None; Kraig S. Bower, None Support: Dept of Defense W81XWH Clinical Trial: NCT Program Number: 3946 Poster Board Number: D0151 CORNEAL INCISION DEPTH ACCURACY STUDY FOR THE LENSAR LASER SYSTEM E Valas Teuma, Craig Smith. R&D, LENSAR Inc, Orlando, FL. Purpose: The LENSAR Laser System (LLS) is a femtosecond laser assisted cataract surgery (FLACS) device. In addition to standard capsulotomy and lens fragmentation, the LLS also provide full thickness clear corneal incisions (CCI) and partial thickness arcuate incisions (AI). This study assesses the accuracy of the corneal incision depth produced by the LLS in an animal model. Methods: Surgery was performed on 27 porcine eyes on three different serial number systems. A full procedure was performed on each eye including suction, docking, biometric scan and a full surgical procedure containing a capsulotomy, lens fragmentation, two 3-plane CCI and two 45-degree AI. Three incision depth modes for the AI were studied: fixed depth, percentage depth and fixed residual stroma. Two CCI depths were studied for the CCI: 50% depth and 30% depth for tunnel start point. Upon completion of each surgery each eye was immediately measured using an OCT system (OptoVue RTVue-100/CA). Results: For 600μm fixed depth incisions the depth was measured to be 603 ± 27 (SD). For 80% depth incisions the depth was measured to be 79.8% ± 2.06 (SD). The average corneal thickness at the incision point was 927μm, making the standard deviation of the incision depth 19.1μm. For incisions intended to provide a fixed residual stroma bed of 125μm, the results were ± 13.0 (SD). For this mode the standard deviation was half that of the fixed depth mode; a significant difference (P<0.001). For CCI incisions with mid-plane tunnels intended to be at 50% cornea depth at the entrance and mid-point, the resulting depth was 45.2% ± 4.42 (SD). For CCI incisions with the mid-plane tunnels intended to be 30% depth at the entrance and 50% depth at the midpoint, the resulting depth at the entrance was 31.8% ±2.95(SD), and at the mid-point measured 48.4% ± 2.67(SD). Conclusions: The LLS provides accurate and repeatable incisions depth regardless of incision mode; below a level where refractive outcome variance would be observed. The fixed residual depth mode provided the highest accuracy in this study, due to the consistent edge contrast seen in the Scheimpflug images of the cornea posterior surface. Fresh porcine eyes may show variable amounts of necrosis in the epithelial cells, resulting in inconsistent transparency and significant variance in light scattering off the anterior surface, impacting measurement accuracy. Commercial Relationships: E Valas Teuma, LENSAR Inc (E); Craig Smith, LENSAR Inc (E) Program Number: 3947 Poster Board Number: D0152 Scheimpflug-based derived aberrometry before and after implantation of different combinations of intracorneal ring segments (ICRS) in keratoconus Nicolas Alejandre-Alba 1, 2, Pablo Perez-Merino 2, Silvia Quintana 1, Pedro Pascual 1, Ignacio Jimenez-Alfaro 1, Susana Marcos 2. 1 Ophthalmology, Fundacion Jimenez-Diaz, Madrid, Spain; 2 Instituto de Óptica Daza de Valdés, Consejo Superior de Investigaciones Científicas, Mdrid, Spain. Purpose: To analyze the changes in corneal aberrations induced by different combinations of triangular section ICRS in keratoconic eyes Methods: 86 keratoconic eyes were evaluated with Scheimpflug tomography (Pentacam by Oculus) before and three months after ICRS implantation (Ferrara-type, triangular section). Corneal aberrations were estimated by virtual ray tracing on anterior and posterior corneal elevation maps, using Zemax, in a 4-mm area centered in the eye s pupil. Eyes were divided in groups according to the combination (1 or 2), geometry (optical zone diameter, OZ, 5 or 6 mm, and ICRS angle, 90, 60, 160, 210 deg); and location (inferior I or superior S) of implanted ICRS: 1-OZ5-160I (6 eyes); 2-OZ5-160I-90S (6 eyes); 1-OZ5-210I (5 eyes) ; 2-OZ6-120I-90S (5 eyes) : 2-OZ6-120I-120S (14 eyes); 2-OZ6-150I-90S (8 eyes); 1-OZ6-150I (19 eyes); 1; OZ6; 210I (8 eyes). Changes in corneal aberrations were analyzed by group. Results: On average ICRS decreased corneal astigmatism by 43% (p<0.001) and corneal coma by 18% (p=0.056). However trefoil increased by ~20% and the overall amount of HOA did not decrease significantly. 5 mm OZ ICRS overall tended to reduce HOA by 39,4% (p=0.09), on average changing coma from 1.23±0.54 μm preop to 0.84±0.50 μm postop (p<0.05), and astigmatism from -5.4±2.6 D preop to -3.5±2.4 D postop (p<0.05). 6 mm OZ ICRS decreased corneal astigmatism (from -5.79±3.17 D preop to -3.14±2.11 D postop; p<0.001) but did not systematically decrease other aberrations. Across groups, coma decreased substantially in 1-OZ5-160I and 1-OZ5-210I (by 21.7% and 39,3%, respectively) and slightly in 2-OZ6-120I-120S (by 12.7%) but increased in 2-OZ6-120I-90S (by 2,9%). Conversely, astigmatism decreased significantly (p<0.05) in the last two groups (by 72,8% and a 55,4% respectively). Conclusions: Estimations of corneal aberrations in patients implanted with ICRS allows evaluation of the optical changes, rather than corneal shape alone. 5 mm OZ ICRS decrease efficiently corneal aberrations. While 6 mm OZ ICRS produce the largest improvement of astigmatism. Understanding the relationships between ICRS geometry /implantation pattern and the change in optical aberrations is crucial to refine nomograms. Commercial Relationships: Nicolas Alejandre-Alba, None; Pablo Perez-Merino, None; Silvia Quintana, None; Pedro Pascual, None; Ignacio Jimenez-Alfaro, None; Susana Marcos, None Program Number: 3948 Poster Board Number: D0153 The Impact of Corneal Epithelium on Corneal Aberrations after LASIK Geunyoung Yoon 1, 2, Scott MacRae 1, 2. 1 Flaum Eye Institute, University of Rochester, Rochester, NY; 2 Center for Visual Science, University of Rochester, Rochester, NY. Purpose: To quantify the contribution of the corneal epithelium to corneal power and higher order aberrations, especially spherical aberrations (SA) after myopic and hyperopic LASIK treatment. Methods: The epithelium thickness profile was modeled for different magnitudes of spherical refractive error correction based on previous results (Reinstein et. al., 2009; Reinstein et. al., 2010).

16 The traditional Munnerlyn equation was applied to simulate the postoperative corneal anterior surface profile. The posterior cornea surface with 6.8mm radius of curvature remained unchanged after ablation. The modeled epithelial thickness profiles were imported into commercially available optical design software (Zemax TM Bellevue, WA) to analyze aberrations induced by the epithelium. This analysis was performed under two different corneal models, (1) single layer cornea i.e. the epithelium thickness was treated as corneal stroma and (2) two-layered cornea in which the refractive indices for the epithelium and corneal stroma were and 1.376, respectively. The difference in the aberration profile between these two conditions represents the epithelium induced aberration. The aberrations analyzed included defocus, primary and higher order SAs (4 th, 6 th and 8 th Zernike radial orders). Results: After myopic LASIK ranged from -1 to -13.5D correction, the epithelium thickness profile was thicker both centrally (7-13mm) and peripherally (2-9mm) compared to preoperative thickness. In contrast, hyperopic LASIK up to +8D correction caused central thinning (8-21mm) and peripheral thickening (10-72mm), demonstrating that variation in epithelium thickness across the cornea after hyperopic LASIK was increased substantially compared to myopic LASIK. In myopic LASIK, the epithelium layer caused little changes in defocus (< 0.05D) and SAs (< 0.01mm) which had almost no impact on overall optical quality of cornea. However, the epithelium layer after hyperopic LASIK induced 0.48D defocus on average, with a greater change with increasing refractive error correction (0.79D for a +8D correction). SAs also changed by 0.055um (4 th SA), 0.014um (6 th SA) and 0.013um (8 th SA). Conclusions: Variation in the epithelium thickness after hyperopic refractive surgery influenced corneal aberration significantly. Therefore, epithelial healing response of the cornea is an important factor to consider for better postoperative refractive outcomes. Commercial Relationships: Geunyoung Yoon, None; Scott MacRae, None Support: NIH EY Program Number: 3949 Poster Board Number: D0154 Detecting Pseudophakic Dysphotopsia within the Lower Bounds of Statistical Analysis Zack Oakey. Ophthalmology, UC Irvine, Irvine, CA. Purpose: It has been shown that the biggest dissatisfier for uncomplicated cataract surgery patients is pseudophakic dysphotopsia (PD). While edge design of an intraocular lens (IOL) impacts this problem, refractive index is still controversial as to its impact. This study was designed to determine the role of increasing refractive index on PD. Methods: This study was conducted at the John A. Moran Eye Center, University of Utah, US. A retrospective chart review identified patients who received one of two hydrophobic acrylic single piece IOLs (AcrySof WF SP [ZCB00] or Tecnis SP [SN60WF]), which differed mainly by refractive index (1.55 vs 1.47). Patients were included if the surgery had been uncomplicated and took place at least a year before study participation. All eligible patients had 20/20 best corrected vision, without any disease known to impact visual quality. In addition to conducting a record review, the enrolled patients were surveyed for PD, using a modified National Eye Institute Visual Function questionnaire, as well as for overall satisfaction with visual quality. Results: Statistical analysis demonstrated PD was 2.98 with wide standard deviation of 4.8 (scale 0-18) via the modified NEIVF. Conclusions: The study suggests that with the two IOLs assessed, in statistical analysis wide variation occurs within lower values but maintains stability and no statistical significance in either group. Commercial Relationships: Zack Oakey, None Program Number: 3950 Poster Board Number: D0155 Post-Lasik refractive results on eyes with thin corneas Paloma Lopez 1, Lorena Lam Franco 1, Jorge E. Valdez 2, Julio C. Hernandez 2, Jesus Merayo 3. 1 Ophthalomology, Centro Medico Zambrano Hellion, Monterrey, Mexico; 2 Cornea and Refractive Surgery Service, Centro Medico Zambrano Hellion, Monterrey, Mexico; 3 Fernández Vega Ophthalmological Institute, Oviedo, Spain. Purpose: To asses Post-Lasik refractive results in a population of topographic normal eyes with central corneal thickness (CCT) under 540μm, in order to co-relate post operative visual acuity and CCT. Methods: Retrospective, observational case series. Records of hispanic patients undergoing refractive surgery at the Cornea and Refractive Surgery Service at the Ophthalomology and Visual Sciences Medical Center Zambrano Helion Institute from January 2012 to January 2014 were evaluated. Patients with preoperative CCT <540μm using Orbscan (Bausch & Lomb) and LASIK surgery were assesed, recording preoperative and post operative visual acuity for further analisis. Results: Mean CCT was 513±65μm with no relationship in age and gender. Uncorrected distance visual acuity (UDVA) before surgery varied from 20/20 to CD 3ft. Nineteen patients (20%) had a postoperative UDVA of 20/400 and 17 (17%) had 20/200. Post operative acuity test results were mostly 20/20 with 76%, 20/15 with 13%. 76% of the patients had a post operative UDVA of 20/20 vision or better. Conclusions: The CCT has no negative impact on the postoperative visual outcomes in patients undergoing LASIK surgery. Results suggest CCT should not be considered a determinant factor during the screening for candidates for ablative excimer laser surgery. Commercial Relationships: Paloma Lopez, None; Lorena Lam Franco, None; Jorge E. Valdez, None; Julio C. Hernandez, None; Jesus Merayo, None Program Number: 3951 Poster Board Number: D0156 Histological Evaluation of Wound Healing in LASIK Flaps with 70 degrees and 120 degrees side cuts Vishal Jhanji, Waiying Li, Kasin Law, Peng Yi, Qian Wang. Ophthalmology & Visual Sciences, Chinese Univ of Hong Kong, Kowloon, Hong Kong. Purpose: To examine early postoperative wound healing in rabbit corneas that had LASIK flaps created with 70 degrees and 115 degrees side cut angle using 150 KHz femtosecond laser. Methods: Sixty-four rabbit corneas were randomized to receive either no surgery (n=36) or corneal flaps (n=36) created with 70 degrees and 115 degrees side cut. Eighteen eyes received only side cuts without lamellar flaps. Animals were sacrificed and corneas were processed as frozen sections. Frozen sections were evaluated with TUNEL assay to detect apoptosis, immunocytochemistry for Ki67 to detect cell mitosis, and immunocytochemistry for CD11b to detect mononuclear cells. Apoptotic cell counts were described in median counts with first to third quartiles. A generalized estimating equation with an exchangeable correlation structure was used for description of effect of surgery on the apoptotic cells. Boferroni adjustments were used for multiple comparisons. Results: Rabbit corneas with 70 degrees side-cut had exhibited more epithelial ingrowth compared to 120 degrees side cut corneas

17 on hematoxylin and eosin staining. All corneas that had received femtosecond laser had TUNEL-positive cells in the anterior stroma in the central as well as peripheral cornea 24 hours after the procedure. No TUNEL-positive stromal cells were detected in control corneas. In the peripheral cornea, 70 degrees side cut generated more apoptotic cells than 120 degrees side cut (P=0.019). The same trend was observed in the central cornea where 70 degrees side-cut and 70 degrees side-cut+lasik induced more apoptotic cells compared to the corneas with120 degrees side cut (P<0.001). Overall, Ki67 expression was significantly higher in corneas with 120 side cut compared to corneas with 70 degrees side cut and, control corneas. CD11b staining was negative in all samples. Conclusions: In our study, 70 degrees side cut triggered more epithleial growth and TUNEL-positive cells in both central and peripheral cornea, compared to 120 degrees side cut. The corneas with 120 degrees side cut expressed more mitotic activity than those with 70 degrees side cut. This disparity may translate into different healing response in the two side cut angle profiles. Program Number: 3952 Poster Board Number: D0157 Histopathological findings in corneal ectasias secondary to refractive surgery Rocio Zamora Ortiz, Abelardo Rodriguez- Reyes, Ivette Hernandez- Ayuzo, Dolores Ríos y Valles-Valles. Ophthalmic Pathology, APEC, Mexico city, Mexico. Purpose: The purpose of the current study was to know the histopathologic characteristics of those patients with clinical history of corneal ectasia secondary to refractive surgery in a large Mexican ophthalmologic referral center in a period of ten years ( ). Methods: A retrospective, observational, cross-sectional, descriptive study was performed. The slides of all corneal buttons stained with H&E, PAS and Masson s trichrome from patients with history of corneal ectasia post refractive surgery treated with penetrating keratoplasty were evaluated. Microscopically, they were measured and photographed with the AxioVision system. The variables studied in the corneal buttons were divided in two different categories: qualitative characteristics which were those alterations in each of the corneal layers and quantitative features, which included full corneal thickness and epithelial thickness. In LASIK cases other measures than flap, were stromal flap and the residual stromal bed thickness respectively. In cases of radiated keratotomy we also measured the epithelial thickness at the incision site and extent of epithelial projections through the stroma at the incision site. Results: A total of 50 specimens from 47 patients were studied. The average of full corneal thickness at the greatest ectasia site was microns and at the epithelium microns. In the LASIK cases, the average thickness of the flap was microns and microns of the residual stromal bed. The most frequent findings were atrophy alternating with epithelial hyperplasia (62%), partial loss of Bowman s layer (42%), decrease of residual stromal bed (73%) and endothelial loss (56%). Conclusions: Alterations of the posterior layers such as decrease of the stromal bed and endothelial loss, are risk factors for corneal ectasia that were confirmed with our results. The current series showed additional anomalies of the anterior corneal layers. In addition to the posterior layers, the alterations of anterior layers increase the development of corneal ectasia. Commercial Relationships: Vishal Jhanji, None; Waiying Li, None; Kasin Law, None; Peng Yi, None; Qian Wang, None Support: Direct Grant No , Chinese University of Hong Kong, Hong Kong Commercial Relationships: Rocio Zamora Ortiz, None; Abelardo Rodriguez- Reyes, None; Ivette Hernandez-Ayuzo, None; Dolores Ríos y Valles-Valles, None