Search

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.

Objective To determine the incidence and severity of complications from laser in situ keratomileusis (LASIK) for the correction of myopia by experienced and inexperienced surgeons. Design Prospective, observational clinical study. Participants Fourteen surgeons and 1062 eyes of 574 myopic patients who desired surgical correction of myopia ranging from −2.00 to −22.50 diopters (D; mean, −7.57 D) and astigmatism no greater than 4.00 D participated in this study. Intervention Myopia was corrected with LASIK. Astigmatism was corrected with arcuate keratotomy at the same time as the initial procedure or subsequently. Main outcome measures Primary outcome measures were change in best spectacle-corrected visual acuity (BSCVA) and the incidence of complications. Results Eyes were followed for a mean of 9.5 months after their last surgical procedure (range, 2 weeks–21 months). Three hundred eighty-one eyes (36%) underwent 468 enhancement procedures 3 months or more after the initial treatment. There were 27 (2.1%) intraoperative and 40 (3.1%) postoperative complications. Laser ablation was not performed during the initial treatment of 17 (1.6%) eyes because of intraoperative complications. Seventy-four eyes gained 2 or more lines of BSCVA, while 50 eyes lost 2 or more lines of BSCVA. Only three eyes lost two or more lines of BSCVA to a level worse than 20/40. One eye with a flap buttonhole (BSCVA 20/50) also had an epiretinal membrane. The second eye (BSCVA 20/60) had a flap buttonhole that may have been related to a previous corneal transplant. The third eye (−22.50 D before surgery) had a rhegmatogenous retinal detachment develop, reducing BSCVA from 20/60 to 20/200. The incidence of intraoperative complications decreased from 3.1% during the first 3 months to 0.7% during the last 9 months of the study ( P = 0.02). Conclusions LASIK is acceptably safe for the correction of myopia. Although complications occur in approximately 5% of cases, these rarely lead to visual loss of more than two Snellen lines and postoperative acuity below 20/40. Flap buttonholes were more likely to cause loss of BSCVA than free or incomplete flaps ( P = 0.02); flap buttonholes may be more likely in eyes that have undergone previous surgery. Complication rates can be reduced as the surgical team gains experience.

Objective This study aimed to determine whether there is a true difference in predictability between single-zone and multizone laser in situ keratomileusis (LASIK) for the correction of low myopia or whether any difference in predictability is because of a need for separate clinical nomograms for the two treatments. Design A prospective, randomized, clinical trial. Participants Fourteen surgeons and 190 eyes of 95 patients with myopia who desired surgical correction of myopia ranging from −2.00 to −7.00 diopters (D) participated. Intervention Fellow eyes of patients with myopia undergoing bilateral simultaneous LASIK were randomized to single-zone and multizone ablation. Astigmatism was not corrected at the time of LASIK. Main outcome measures Predictability, postoperative videokeratography, and contrast sensitivity were assessed at 3 months after surgery. Results At 3 months, r 2 values relating laser setting to change in spherical equivalent refraction were 0.78 for single-zone and 0.76 for multizone ablation; mean outcome with respect to intended was −0.84 D (0.65 standard deviation [SD]) for single-zone and −0.62 D (0.78 SD) for multizone eyes ( P = 0.035). There was no relationship between single-zone and multizone ablation and the likelihood of asymmetric postoperative videokeratography ( P = 0.83). The only difference in contrast sensitivity was a significantly greater decrease in log contrast for multizone eyes at 12 cyc/deg under undilated conditions. Conclusions There is no true difference in predictability between single-zone and multizone LASIK for the correction of low myopia. Separate clinical nomograms for single-zone and multizone LASIK should eliminate the difference in predictability that was observed in this clinical trial.