Changes in Descemet's membrane and endothelium after photorefractive keratectomy in rabbits

OBJECTIVE: To investigate the effects of epithelial abrasion on the corneal endothelium and Descemet's membrane and to compare the changes with those after eximer laser photoablation of the cornea. METHODS: The animal models of corneal epithelial abrasion and excimer laser photoablation of the cornea were performed on the rabbit eyes. The central epithelial abrasion, 7 mm in diameter, was created by mechanical removal of the epithelium, and the specimens were examined at 24 hours, 7 days, 14 days and 30 days by transmission and scanning electron microscopy. Corneas that were photoablated by an excimer laser and non-treated normal corneas were investigated as controls. RESULTS: (1) Corneas with the epithelium removal showed massive enlargement of the mitochondria in the endothelium and exhibited a layer of electron-dense fibrillogranular material that had migrated forward through the Descemet's membrane. These alterations were similar to the changes observed after photoablation of the cornea by an excimer laser. (2) The edema and pathologic changes of corneal endothelium in eyes with denuded epithelium alone were similar to that observed after photoablation of the cornea by an excimer laser. CONCLUSION: The extrusion of electron-dense material in the Descemet's membrane observed after excimer laser ablation destruction of the epithelial integrity.