Twenty percent alcohol toxicity on rabbit corneal epithelial cells: electron microscopic study.

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 keratectomy) instruments and then washed with sterile water. Zero time, 1, 3, 5 days after ethanol treatment, corneas were excised and examined with scanning and transmission electron microscopy (SEM and TEM).

Results: Widespread partial or total damage of microvilli, focal breaks of intercellular junction, and cellular edema was observed. The damage was more severe in corneas with longer ethanol treatment. In corneas with ethanol treatment more than 1 minute, slough of superficial corneal epithelium occurred and progressed with time. Two-minute ethanol treatment resulted in complete destruction of microvilli and significant separation of intercellular junction. These pathologic changes persisted 5 days after ethanol treatment.

Conclusions: From these results, increasing exposure time to ethanol more than 1 minute results in significant damage to superficial corneal epithelium and prolongs its normal recovery time.