Excimer laser photorefractive keratectomy for high myopia and myopic astigmatism

BACKGROUND AND OBJECTIVE: To determine the efficacy, safety, and predictabi lity of excimer laser photorefractive keratectomy of high myopia and myopic astigmatism. PATIENTS AND METHODS: 76 eyes of 52 patients with myopia from -8.00 to -23. 50 diopters (D) with or without astigmatism up to -5.50D were treated with the VISX 20/20 excimer laser (VISK, Santa Clara, CA) and a multi-zone ablat ion technique. Visual acuity, manifest refraction, corneal haze, and topogr aphy were evaluated at 1 week and 1, 3, 6, 12, and 18 months postoperativel y. RESULTS: Postoperative refractions were generally stable after 12 months. A t the last follow-up all patients were within -1.96 D of-the intended corre ction. Eighteen months postoperatively, 68% of patients undergoing photoref ractive keratectomy (PRK), and 65% of patients undergoing photo astigmatic refractive keratectomy (PARK), were within I D of planned refraction. Furth ermore, 87% of patients after PRK and 80% of patients after PARK had a visu al acuity of 20/40 or better. CONCLUSIONS: High myopia with or without astigmatism was successfully treat ed in most of the patients using PRK. The stability of the postoperative re fraction during the first 18 months seems to be good. The incidence of-adve rse effects was low but improvements in the future should further reduce co mplications, thus increasing the safety of refractive procedures.