results of photorefractive keratectomy for high myopia in noor clinic of tehran

many studies have shown the effectiveness of photorefractive keratectomy (prk) in correction of vision in low and moderate myopia. to evaluate the results of 193-nm exeimer laser photorefractive keratectomy for highly myopic eyes, we reviewed refractive outcome of 43 eyes of 30 patients. most eyes were treated with 1-step operation, using a 6 mm optical zone. 43 eyes were treated for myopia, which were between -6.40 and -16.90 diopters. the mean pre-operative refraction was -9.50 d. all eyes were followed for at least 12 months. at 12tht month visit, 30.2% and 60.5% of eyes achieved correction within 1 and 2 d of attempted correction, respectively. at this time, 62.7% of eyes obtained 20/40 visual acuity or better uncorrected. at 1 year, 13% and 8% of eyes lost 3 and 4 lines of best-corrected visual acuity, respectively. also 13% of eyes lost 2 lines. 12 months after prk, 5 eyes developed corneal haze grade 2 and 2 eyes, grade 3 (0-5 scale). there was much undercorrection seen in this group compared with patients undergoing prk for low and moderate myopia. photorefractive keratectomy for high myopia, though effective, is not a safe and accurate procedure and is less predictable and stable than performing it for low and moderate myopia.