Predictability of Excimer Laser Treatment of Myopia

Abstract

Objective: To prospectively examine the predictability of excimer laser photorefractive keratectomy and photoastigmatic refractive keratectomy for myopia that ranged from −1 to −18 diopters (D). Methods: Patients were treated with an excimer laser and followed up prospectively for 12 months. Low myopia was treated in one ablation zone (6.0 mm), high myopia in two ablation zones (5.0 and 6.0 mm), and extreme myopia in three ablation zones (4.5, 5.0, and 6.0 mm) with a maximum treatment of 15 D. Data were analyzed to determine the distribution of the various postoperative outcomes by preoperative myopia. Results: Two hundred seventy-four low myopes, 189 high myopes, and 41 extreme myopes were available for 12-month follow-up. The re-treatment rate increased with preoperative myopia. The predictability of refraction and uncorrected and best corrected visual acuity progressively decreased with increasing myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. Conclusion: These data should help in the counseling of patients about the likely outcome if they have excimer laser surgery to correct myopia.