Scanning electron microscopy comparison of corneal epithelial removal techniques before photorefractive keratectomy

Purpose: To evaluate and compare the most common epithelial removal techniq ues by scanning electron microscopy. Settings: Beckman Laser Institute, University of California, Irvine, Califo rnia, USA. Methods: The epithelium was removed in both eyes of 5 Dutch belted rabbits by 1 of 5 techniques: blunt mechanical debridement (with a blunt spatula), sharp mechanical debridement (with a sharp scalpel blade), application of t opical alcohol, and transepithelial removal with the excimer laser and with the rotary epithelial scrubber. The animals were immediately killed and co rneal specimens prepared for scanning electron microscopy. The degree of co rneal trauma and the completeness of epithelial cell removal with the 5 tec hniques were evaluated by comparing the regularity and smoothness of the re sulting stromal surfaces. Results: Epithelial removal with alcohol, the excimer beam, and the rotary epithelial scrubber produced a smoother, more uniform anterior stromal surf ace than blunt and sharp mechanical debridement. Conclusions: The smooth and uniform anterior stroma surface produced with t he rotary epithelial scrubber, alcohol, and the laser beam may be preferabl e prior to photorefractive keratectomy. (C) 1999 ASCRS and ESCRS.