Comparing conventional and wavefront-optimized LASIK for the treatment of hyperopia.

PURPOSE: To compare differences in visual outcomes and induced spherical aberration after conventional and wavefront-optimized LASIK for the treatment of hyperopia. METHODS: In a prospective, randomized, single-center clinical trial, 51 consecutive eyes underwent LASIK for the treatment of hyperopia. Eyes were divided between groups treated with conventional LASIK with the Alcon LADAR4000 excimer laser (n=25) and wavefront-optimized LASIK with the WaveLight ALLEGRETTO excimer laser (n=26). Refractive and visual outcomes, induced spherical aberrations, and contrast sensitivity were analyzed. RESULTS: On postoperative day 1, 20% of eyes treated with a conventional profile had uncorrected visual acuity (UCVA) of 20/20 or better compared to 65% of eyes receiving wavefront-optimized treatment (P=.0011). By 6 months, UCVA was 20/20 or better in 72% and 84% of the conventional and wavefront-optimized treatment groups, respectively (P=.3254). At 6 months, the manifest refraction spherical equivalent was -0.21+/-0.47 diopters (D) and 0.16+/-0.27 D (P=.6469) whereas the cylinder was -0.41+/-0.47 D and -0.17+/-0.27 D (P=.0332) for the conventional and wavefront-optimized treatment groups, respectively. Induced spherical aberration was -0.54+/-0.32 microm and -0.42+/-0.21 microm for the conventional and wavefront-optimized treatment groups, respectively (P=.1195). The respective change in mesopic and photopic area under the log contrast sensitivity function was -0.05+/-0.29 and -0.05+/-0.23 for the conventional treatment group and 0.08+/-0.39 and 0.08+/-0.41 for the wavefront-optimized treatment group (P=.1970). CONCLUSIONS: Wavefront-optimized (ALLEGRETTO) and conventional (LADAR4000) ablation predictably and safely correct low to moderate hyperopia. Wavefront-optimized ablation showed superior results with regards to rapid visual recovery and residual cylinder. Although not statistically significant, a trend towards less induced negative spherical aberrations and improved mesopic and photopic contrast sensitivity was noted with wavefront-optimized treatment.

Corneal endothelial cell density after femtosecond thin-flap LASIK and PRK for myopia: a contralateral eye study.

PURPOSE: To compare the effect of femtosecond thinflap LASIK and photorefractive keratectomy (PRK) on postoperative endothelial cell density. METHODS: In a prospective, randomized, contralateral, single-center clinical trial, 25 patients (mean age: 30+/-5 years [range: 21 to 38 years]) underwent PRK in one eye and thin-flap LASIK in the fellow eye for the correction of myopia using a wavefront-guided platform. The central corneal endothelial cell density was measured using the NIDEK Confoscan 4 preoperatively, and at 1 and 3 months postoperatively. Changes in endothelial cell density were analyzed over time between the two refractive techniques. RESULTS: In PRK, the average preoperative endothelial cell density was 3011+/-329 cells/mm(2), which decreased to 2951+/-327 cells/mm(2) at 1 month (P=.5736) and 2982+/-365 cells/mm(2) at 3 months (P=.6513). In thinflap LASIK, the average preoperative endothelial cell density was 2995+/-325 cells/mm(2), which decreased to 2977+/-358 cells/mm(2) at 1 month (P=.5756) and 2931+/-369 cells/mm(2) at 3 months (P=.4106). No statistically significant difference was found between the two groups at 1 (P=.7404) or 3 (P=.3208) months postoperatively. CONCLUSIONS: No statistically significant change was noted in endothelial cell density following either PRK or thin-flap LASIK for the treatment of myopia. Furthermore, no statistically significant difference was found between the two groups out to 3 months postoperatively, indicating that thin-flap LASIK is as safe as PRK with regards to endothelial health.

Association between ocular dominance and refraction.

PURPOSE: To investigate the association between ocular dominance and refraction. METHODS: A retrospective study of the cycloplegic refraction of 2453 consecutive patients with a mean age of 46 +/- 12 years (range: 18 to 79 years) was performed. One thousand one hundred fifty-seven (47%) patients were men and 1296 (53%) were women. Patients who had previous eye surgery, ocular disease, or > 2 lines of best spectacle-corrected visual acuity (BSCVA) difference between eyes were excluded. Motor ocular dominance was determined using the hole-in-the-card test. RESULTS: The right and left eyes were dominant in 67% (1650) and 33% (803) of patients, respectively. Males had a higher right eye dominance (70%) than females (65%) (P = .0168) with a mean cycloplegic spherical equivalent refracton (SE) of -2.12 diopters (D) and -2.38 D, respectively. This higher rate of right eye dominance in males was seen at all levels of SE refractive error. Mean BSCVA was 20/19 in both right and left eyes (P>.05) with a mean SE of -2.25 +/- 3.63 D and -2.26 +/- 3.66 D in the right and left eyes, respectively. Neither mean SE difference nor BSCVA difference between eyes was found to correlate with motor eye dominance. CONCLUSIONS: Gender appears to be a factor when testing ocular dominance but not SE refractive error. The hole-in-the-card dominance test is a method that is easy to perform for both patients and clinicians.

Conductive keratoplasty for presbyopia: 3-year results.

PURPOSE: To assess the long-term safety, efficacy, and stability of conductive keratoplasty (CK) in the treatment of presbyopia. METHODS: Ten near-plano presbyopic patients (6 women and 4 men) underwent unilateral CK with standard-pressure technique in the non-dominant eye to improve their near vision. Mean age was 51+/-3.1 years (range: 46 to 56 years). Nine of the 10 patients were available for both 1- and 3-year follow-up examinations. RESULTS: Preoperative mean manifest refraction spherical equivalent (MRSE) was -0.17+/-0.29 diopters (D), yielding a mean near uncorrected visual acuity (UCVA) of J10. Three years after CK, the mean near UCVA was J3. The mean MRSE at 3 years was -1.06+/-0.81 D, which represents a 0.25 D change from the MRSE at 1 year. The MRSE in the dominant untreated eyes had a +0.26 D change during the 3-year period, which was not statistically different when compared to the CK-treated eyes during the 3-year postoperative period. No eye lost best spectacle-corrected visual acuity or had induced cylinder > or =0.75 D. Seventy-eight percent had binocular distance UCVA 20/20 or better and near UCVA J3 or better. The average keratometry remained stable at 45.09 D 3 years postoperatively compared to 45.08 D 1 year postoperatively. CONCLUSIONS: Conductive keratoplasty for the treatment of presbyopia provided safe, effective, predictable, and stable results 3 years following the initial surgery. Refractive stability was similar for both the CK-treated and untreated eyes with a small hyperopic shift noted during the 3-year follow-up period.

Anterior segment OCT analysis of thin IntraLase femtosecond flaps.

PURPOSE: Anterior segment optical coherence tomography (OCT) was used to analyze thin flaps created with the IntraLase femtosecond laser (IntraLase Corp). METHODS: Twenty-five eyes of 25 patients had flaps created with the 60 kHz IntraLase femtosecond laser prior to excimer laser ablation. The desired flap thickness was 110 microm with a diameter of 8.5 mm for all eyes. At 1 month postoperatively, all eyes were evaluated with the Visante anterior segment OCT (Carl Zeiss Meditec). Four thickness measurements were obtained across the length of the flaps at the meridians of 45 degrees, 90 degrees, 135 degrees, and 180 degrees. Thus, 16 thickness measurements were analyzed for each flap. RESULTS: Flaps were uniform (planar) with a mean thickness of 112 +/- 5 microm (range: 87 to 118 microm). Average standard deviation within the individual flaps was 4 microm (range: 1 to 8 microm). CONCLUSIONS: The IntraLase femtosecond laser creates thin, uniform (planar) flaps with high predictability and reproducibility.

Conductive keratoplasty for presbyopia: 1-year results.

PURPOSE: To assess the safety, efficacy, and stability of conductive keratoplasty (CK) in the treatment of presbyopia. METHODS: Ten near plano presbyopic patients (6 women and 4 men) underwent unilateral CK in the non-dominant eye to improve their near vision. Mean age was 51 +/- 3.1 years (range: 46 to 56 years). The surgeries were the author's first 10 CK procedures performed. The postoperative target for these eyes ranged from -1.25 to -1.75 diopters (D). RESULTS: Preoperative mean manifest refraction spherical equivalent (MRSE) was -0.18 +/- 0.27 D (range: -0.75 to -0.25 D), yielding a mean near uncorrected visual acuity (UCVA) of J10 (range: J12 to J5). Twelve months after CK, the mean near UCVA was J1 (range: J3 to J1) with 90% (9/10) eyes J1 and 100% (10/10) eyes J3 or better. The mean MRSE was -1.31 +/- 0.53 D (range: -2.25 to -0.75 D). Treated eyes lost an average of 2.2 +/- 2 lines (range: 0 to 5) of distance UCVA but gained an average of 8.7 +/- 2 lines (range: 4 to 11) of near UCVA. No eye lost best spectacle-corrected visual acuity or had induced cylinder > or = 0.75 D. Nine (90%) of 10 patients had binocular distance UCVA < or = 20/20 and near UCVA < or = J1 and all 10 (100%) patients had binocular distance UCVA < or = 20/25 and near UCVA < or = J3. CONCLUSIONS: Conductive keratoplasty for the treatment of presbyopia provided safe and effective results 1 year following the initial surgery. Longer follow-up will be needed to describe refractive stability. The mean near and distance UCVA results were better than expected for the amount of refractive change observed during this study.

Alcon LADARWave customcornea retreatments.

PURPOSE: To present our experience performing wavefront-guided ablations for the treatment of residual refractive error following previous refractive surgery. METHODS: Four different cases are presented-1) primary wavefront-guided LASIK; 2) wavefront-guided lift-flap LASIK retreatment; 3) wavefront-guided photorefractive keratectomy (PRK) retreatment; and 4) wavefront-guided PRK over radial keratotomy retreatment. All procedures were performed with the Alcon CustomCornea laser platform. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and wavefront analysis (6.5-mm pupil) were performed preoperatively and 3 months after CustomCornea retreatment. The Alcon LADARWave device was used for wavefront measurements. RESULTS: Total lower order and higher order aberrations were decreased following wavefront-guided retreatment, resulting in improved quality of vision. The maximum target offset (+ 0.75 diopters) can be used to prevent an overcorrection of defocus (myopia) when treating a significant amount of spherical aberration. CONCLUSIONS: Wavefront-guided ablation was an effective treatment for residual lower and higher order aberrations following previous refractive surgery. Custom ablation treatment algorithms need to be developed specifically for retreatment procedures.

Ocular cyclotorsion during customized laser ablation.

PURPOSE: To compare the measured difference and degree of cyclotorsion in eyes undergoing customized laser ablation between the time of wavefront measurement and laser refractive surgery. METHODS: The degree of cyclotorsion was measured in 1019 consecutive eyes of 732 patients who underwent wavefront-guided corneal ablation for the treatment of myopia with or without astigmatism with the Alcon LADARVision excimer laser. Prior to obtaining the wavefront measurement, the horizontal axis of each eye was marked. Cyclotorsional alignment was measured on the supine patient prior to beginning the laser. RESULTS: The predominant trend was for excyclotorsion. The total range of torsion in degrees was 0.5 degrees to 17.5 degrees (mean: 4.05 +/- 2.9 degrees). Cyclotorsion > 2 degrees occurred in 68% of all eyes. In the right eyes, 83% excyclotorted, 14% incyclotorted, and 3% displayed no torsion. In the left eyes, 62% excyclotorted, 34% incyclotorted, and 4% exhibited no torsion. In a subset of 112 patients undergoing simultaneous bilateral surgery, 46% displayed bilateral excyclotorsion and 1.7% displayed bilateral incyclotorsion. CONCLUSIONS: In this study, the majority of eyes had a low to moderate amount of cyclotorsion observed with the change of orientation from seated to supine position. Excyclotorsion was the predominant pattern. Proper registration prior to wavefront-guided corneal ablation is essential for proper correction of astigmatism and higher order aberrations to achieve optimal visual outcomes.