photorefractive keratectomy for myopia; an 8-year follow up study

purpose: to evaluate the 8-year results of excimer laser photorefractive keratectomy (prk) for myopia in terms of safety, stability and late complications. methods: of 203 myopic patients who underwent prk with single-step method using nidek ec-5000 excimer laser with 5-6 mm ablation zones at basir eye center, tehran-iran from 1996 to 1998, 179 eyes of 98 patients who completed 8 years of follow up were included in this study. results of follow up examinations at 1, 3, 6 and 12 months and 2 and 8 years after surgery were analyzed. treated eyes were divided into three groups according to preoperative refractive error: low (≤ -6.00 diopter [d]), medium (-6.10 to -10.00 d) and high (> -10.00 d) myopes. results: eight years after prk, emmetropia (within ±1 d) was achieved in 69.1%, 30% and 46.15% of the low, medium and high myopia groups, respectively. although a small myopic shift occurred up to 8 years after surgery, myopic regression stabilized in all groups within 24 months and was correlated significantly to preoperative spherical equivalent refraction. corneal haze occurred in 5% especially in medium and high myopic groups but cleared within two years in 89% of cases. only one eye lost two lines of best spectacle-corrected visual acuity due to corneal haze. conclusion: according to this study, postoperative refraction remains stable two years after prk and most cases of corneal haze clear within two years after surgery. therefore, prk seems to be a safe and stable surgical procedure in myopic patients.