Complications of laser in situ keratomileusis for the correction of myopia

Objective: To determine the incidence and severity of complications from la ser in situ keratomileusis (LASIK) for the correction of myopia by experien ced and inexperienced surgeons. Design: Prospective, observational clinical study. Participants: Fourteen surgeons and 1062 eyes of 574 myopic patients who de sired 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 th is study. Intervention: Myopia was corrected with LASIK. Astigmatism was corrected wi th arcuate keratotomy at the same time as the initial procedure or subseque ntly. Main Outcome Measurer Primary outcome measures were change in best spectacl e-corrected visual acuity (BSCVA) and the incidence of complications. Results: Eyes were followed for a mean of 9.5 months after their last surgi cal 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 treatmen t of 17 (1.6%) eyes because of intraoperative complications. Seventy-four e yes gained 2 or move 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 tha n 20/40. One eye with a flap buttonhole (BSCVA 20/50) also had an epiretina l membrane. The second eye (BSCVA 20/60) had a flap buttonhole that may hav e been related to a previous corneal transplant. The third eye (-22.50 D be fore surgery) had a rhegmatogenous retinal detachment develop, reducing BSC VA from 20/60 to 20/200. The incidence of intraoperative complications decr eased 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. Althoug h complications occur in approximately 5% of cases, these rarely lead to vi sual 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 i ncomplete flaps (P = 0.02); flap buttonholes may be more likely in eyes tha t have undergone previous surgery. Complication rates can be reduced as the surgical team gains experience.