RESUMO
PURPOSE: To evaluate 20% ethanol toxicity on the rabbit corneal epithelium, ethanol-treated rabbit corneas were examined with electron microscopy. METHODS: Rabbit corneas(24 eyes) were treated with 20% ethanol for 30 seconds, 1 minute, and 2 minutes by using LASEK(Laser Assisted Subepithelial Keratomileusis) instruments, and washed with sterile water. Zero time, 1, 3, 5 days after ethanol treatment, corneas were excised and examined with scanning and transmission electron microscopy. RESULTS: Widespread damage or disappearance of microvilli and local breaks of intercellular junction were observed. The changes were more severe in corneas with longer ethanol treament. In corneas with over 1 minute ethanol treatment, slough of superficial corneal epithelium was shown and increased with time. It was difficult to recognize microvilli or distinctive intercellular junction in corneas with 2 minute-treament. These pathologic changes persisted 5 days after ethanol-treatment. CONCLUSIONS: From these results, 30 seconds to 1 minute-ethanol treatment is recommended in corneal surgery to avoid severe, persisting damage of superficial corneal epithelium.
