Long-Term Evaluation of Complications and Results of Photorefractive Keratectomy in Myopia: An 8-Year Follow-Up

Abstract

To evaluate 8-year results of photorefractive keratectomy (PRK) for myopia in terms of safety, efficacy, stability, and late complications. From 371 myopic eyes of 203 patients who underwent PRK using NIDEK EC-5000 excimer laser with 5.5- to 6-mm ablation zones in Basir Eye Center, Tehran, Iran, during 1997-1998, data of 179 myopic eyes of 98 patients, who participated in annual examinations, were analyzed. Treated eyes were divided into 3 groups according to preoperative refraction: low myopia [<or=-6.00 diopters (D)], moderate myopia (-6.10 to -10.00 D), and high myopia (>-10.00 D). The main outcome measures were safety, efficacy, stability, and postoperative complications. Eight years after PRK, 69.64%, 44.44%, and 45.65% of the low, moderate, and high myopic groups were within +/-0.5 D of emmetropia. Sixteen eyes (4.31% of original cases) underwent retreatment mainly because of regression. Although a small myopic shift occurred up to 8 years after surgery, changes in myopic regression stabilized in all myopic groups within 24 months. Four eyes (2.06%) lost 2 lines of best spectacle-corrected visual acuity (1 eye for corneal haze and other 3 for problems not related to refractive surgery). Corneal haze occurred in 11.34% especially in medium and high myopic groups, but it cleared within 2 years in 68.2% of cases. Based on our study, PRK seems to be a safe, efficient, and stable surgical procedure, and if patients obtain a good result with the initial treatment, then their results are relatively stable over time.