ABSTRACT
BACKGROUND AND OBJECTIVE: Excimer laser photorefractive keratectomy (PRK) is quickly establishing itself as a dependable treatment modality for the correction of myopia. We review in this report our experience with the Summit OmniMed UV200 excimer laser (Summit Technology, Inc., Waltham, MA) in the treatment of low to high degrees of myopia. PATIENTS AND METHODS: We retrospectively analyzed the results of excimer laser PRK in 139 eyes of 127 patients treated between November 1993 and August 1994. RESULTS: The study population was comprised of 75 males and 52 females with a mean ago of 26.9 +/- 6.21 years (range, 19 to 52 years). All patients were followed for at least six months and the mean follow-up was 11.7 +/- 3.63 months (range, 6 to 22 months). Mean pre-operative myopia was -8.23 +/- 3.32 diopters (D) (-2.63 to -19.50 D). Of 139 eyes, 101 (72.7%) had a pre-operative myopia greater than -6.00 D; and 32 (23.0%) had a pre-operative myopia greater than -10.00 D. At last follow-up, 73 (52.5%) eyes were within +/-1.00 D of emmetropia, 92 (66.2%) eyes had an uncorrected visual acuity of > or = 6/12, and 12 (8.6%) eyes lost 2 or more lines of spectacle corrected visual acuity. Severe corneal haze (grade 3 to 4) was seen in 20 (14.4%) eyes at last follow-up. Complications encountered in this series included steroid response in 15 (10.8%) eyes, and reactivation of herpes simplex keratitis in one (0.7%) eye. Statistical analysis reveals that the only risk factor independently associated with regression > or = 2.00 D following PRK is the occurrence of severe corneal haze (grade 3 and 4). CONCLUSION: Excimer laser PRK appears to be a safe and predictable method for the treatment of myopia < 6.00 D. With higher degrees of myopia the results appeared to be more guarded, mainly due to the healing pattern of the cornea following single zone myopic ablations.
