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

Abstract

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.

Single-step transepithelial versus alcohol-assisted photorefractive keratectomy in the treatment of high myopia: a comparative evaluation over 12 months

“…Our results with both EtOH-PRK and TransPRK are similar to recent results published literature with EtOH-PRK in high myopia 13 14. Interestingly, Shapira et al have noted slight undercorrection with TransPRK as compared EtOH-PRK and mechanical PRK on the Allegretto Wave Excimer Laser platform.…”

Fine tuning of the default depth and rate of ablation of the epithelium in customized trans-epithelial one-step superficial refractive excimer laser ablation

“…The coefficient of correlation R should be greater than 0.70 to show a good linear correlation. The coefficient of determination, denoted by R [2], was calculated to measure the percentage of variability of R in function of the variability of E. It ranges in value from 0 to 100%. The coefficient of determination R 2 should be greater than or equal to 50%.…”

“…In order to perform trans-epithelial refractive laser ablation, the exact knowledge of the epithelial thickness and the ablation rate of the epithelium and of the stroma is mandatory. Excess ablation wastes stromal tissue and variations in epithelial thickness of the ablated area may influence refractive outcome [1,2]. Under-estimation of these parameters may contribute to a reduction of the optical zone while an incorrect evaluation of the epithelium profile to be ablated may affect the aspherical treatment outcome due to the different ablation rate and, consequently, different ablation profile.…”

“…South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, Australia. 2 Brisbane Laser Sight Clinic, Brisbane, Australia. 3 Ashford Advanced Eye Care, Adelaide, Australia.…”

“…These include mechanical debridement with a spatula or similar instrument, an automated brush or with a keratome, sometimes facilitated by prior exposure of the epithelium to alcohol. The area thus denuded of epithelium is of necessity larger than the area of stromal ablation and invariably has an irregular edge [1][2][3].…”