Prospective randomized comparison of simultaneous and sequential bilateral laser in situ keratomileusis for the correction of myopia

Objective: To study the safety and efficacy of simultaneous bilateral laser in situ keratomileusis (LASIK). Design: Prospective randomized clinical trial. Participants: Fourteen surgeons and 714 consecutive eyes of 357 patients who desired surgical correction of myopia ranging from -2.00 to -22.50 diopters. Intervention: Patients were randomized to simultaneous or sequential bilateral LASIK, Main Outcome Measures: Primary outcome measures were safety and efficacy. Procedure safety was assessed, for simultaneous and sequential groups, by comparison of intraoperative and postoperative complication rates and the percentage of eyes losing two or more lines of spectacle-corrected visual acuity. Procedure efficacy was assessed by comparison of the percentage of eyes with uncorrected visual acuity better than or equal to 20/20 and 20/40 and the percentage of eyes within +/-0.50 and +/-1.00 diopters of intended outcome. Results: Three hundred seventy-eight eyes were enrolled in the simultaneous group, and 331 eyes were enrolled in the sequential group. Mean follow-up was 10 months (+/-4.2 months standard deviation; range, 2 weeks-22 months). There was no significant difference in intraoperative complication rate (P = 0.55), loss of two or more lines of spectacle-corrected visual acuity (P = 0.87), or percentage of eyes within +/-0.50 diopters of intended correction (P = 0.17) between simultaneous and sequential groups. Postoperative complications were not significantly different in the two groups except for the unexplained more frequent epithelial ingrowth in the simultaneous group (2.9%) than in the sequential group (0.6%), The adjusted odds ratio for epithelial ingrowth in the simultaneous group was 1.02 (95% confidence interval, 1.01-1.08). There was no increased likelihood of epithelial ingrowth in the second of two simultaneously treated eyes (P = 0.95). Conclusion: The outcomes and complications of performing bilateral simultaneous LASIK were not significantly different from those of sequential treatments, with the unexplained exception of more frequent epithelial ingrowth in the simultaneous group.