Reoperations after photorefractive keratectomy for moderate and high myopia

Abstract

Purpose: To contribute data regarding results of reoperation with excimer laser for the treatment of residual myopia, and to improve corneal clarity following previous photorefractive keratectomy for 'moderate' (< - 9 D) and 'high' (> - 9 D) myopia. Methods: Surface reablations with excimer laser (5 mm treatment diameter) were performed to correct residual myopia and remove subepithelial scars. Refraction, visual acuity, and corneal clarity were recorded with average follow-up of one and two years after reoperation. Results: In 27 eyes with 'moderate' myopia before the first operation, significant improvement was obtained regarding refraction (changed from -2.3 ± 1.56 D before retreatment to -0.58 ± 1.31 D after retreatment (p < 10-3)), and uncorrected visual acuity (improved to ≤ 0.8 in 51.8% of the cases). All cases (6 eyes) with corneal scars improved. Six eyes with 'high' myopia showed no improvement of refraction following reoperation. Effects on corneal clarity were mixed in that group. Conclusion: We were able to improve the results of photorefractive keratectomy for 'moderate' myopia with a second excimer laser ablation. The risks involved in retreatments of such eyes are small. In 'high' myopia, reablations with a 5 mm treatment zone did not improve the refractive outcome on a long-term basis.