Alcohol versus mechanical epithelial debridement: Effect on underlying cornea before excimer laser surgery

Purpose: To determine the effects of 70% isopropyl alcohol used for corneal debridement on surface smoothness, stromal keratocytes, and ease of epithelial removal. Setting: Cornea Research Laboratory, University of Rochester, and Excimer Laser Laboratory, Genesee Valley Eye Institute, Rochester, New York, USA. Methods: Rabbit corneas were de-epithelialized mechanically or with 70% alcohol. The rabbits were split into groups and evaluated immediately or after a 50 mu m deep excimer laser phototherapeutic keratectomy. All tissue was evaluated and compared in terms of surface smoothness parameters, loss of keratocytes, and inflammatory response to de-epithelialization. Results: Computerized laser interferometric microscopy showed no between-group difference in the surface smoothness parameters. There was a marked absence of keratocytes in the superficial 25% of the corneal stroma. The loss of keratocytes was significantly higher (P < .001) in corneas treated with isopropyl alcohol. The inflammatory response 24 hours after epithelial removal was significantly higher (P < .001) in the corneas treated with alcohol. Conclusion: The use of 70% isopropyl alcohol applied for 2 minutes for epithelial removal did not enhance the quality of the subsequent excimer laser procedure. In contrast, isopropyl alcohol increased the inflammatory response, and it may have damaging effects on keratocytes. We would not advocate the use of 70% isopropyl alcohol as administered in our study to remove corneal epithelium before excimer laser surgery.