PREDICTABILITY OF EXCIMER-LASER TREATMENT OF MYOPIA

Objective: To prospectively examine the predictability of excimer lase r photorefractive keratectomy and photoastigmatic refractive keratecto my for myopia that ranged from -1 to -18 diopters (D). Methods: Patien ts were treated with an excimer laser and followed up prospectively fo r 12 months. Low myopia was treated in one ablation zone (6.0 mm), hig h 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 vario us 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 increas ing myopia. The likelihood of losing lines of best corrected visual ac uity and corneal haze increased with increasing myopia. Conclusion: Th ese data should help in the counseling of patients about the likely ou tcome if they have excimer laser surgery to correct myopia.