Comparison of Three Epithelial Removal Techniques in PRK: Mechanical, Alcohol-assisted, and Transepithelial Laser

Abstract

PURPOSE: To compare the visual and refractive results obtained after photorefractive keratectomy (PRK) in patients who underwent one of three different epithelial removal techniques. METHODS: The authors reviewed the medical files of consecutive eyes with myopia and myopic astigmatism that were treated during a 10-year period by mechanical PRK, alcohol-assisted PRK, or transepithelial PRK (in the phototherapeutic keratectomy mode), and observed for more than 1 year. RESULTS: A total of 3,417 patients (3,417 eyes) were included in this study. At 3 and 6 months postoperatively, the outcome of alcohol-assisted PRK was superior both in efficacy (P < .01) and safety (P < .001) to those of both mechanical PRK and transepithelial PRK, which were similar. At more than 1 year postoperatively, the mean efficacy index was still high for alcohol-assisted PRK, but low for the transepithelial PRK, corresponding to a mean uncorrected visual acuity of more than one Snellen line lower than those of the other two techniques (P < .0001). All three techniques showed a regression toward myopia more than 1 year postoperatively, with significant undercorrection obtained in eyes treated with transepithelial PRK (P < .0001). CONCLUSIONS: Significant differences were detected in both the visual outcomes and the refractive results of the three epithelial removal techniques. The long-term outcomes were best for alcohol-assisted PRK.