Time-Delayed, Two-Step Excimer Laser Photorefractive Keratectomy to Correct High Myopia

Abstract

Besides scarring, undercorrection is an important complication of photorefractive keratectomy in myopes over 10.00 diopters. We performed a two-step, time-delayed photorefractive keratectomy with two different ablation zone diameters in a 24-year-old female with amblyopia to correct to total myopic refraction error of -10.75 D. In the first session, a simple myopic correction of -6.50 D with a 5-millimeter ablation zone was performed, and 6 months later, a second myopic correction of -4.00 D with a 6.5-millimeter ablation zone was performed. Four months after the second photorefractive keratectomy with an ablation zone of 6.5 mm, the refraction was +0.75 -2.25 x 40 degrees and stayed constant for 2 more months. After the second treatment, an initial increase in corneal haze was seen, but after 4 months, the corneal haze did not exceed the status before the second treatment. A planned two-step, time-delayed photorefractive keratectomy with a larger second ablation zone is a possible approach to overcoming the problem of undercorrection and regression in high myopia.