Antioxidant Protection against Corneal Damage by Free Radicals during Phacoemulsification

Abstract

PURPOSE: To examine the role of ascorbic acid in reducing corneal endothelial cell loss secondary to high-energy ultrasound energy during phacoemulsification surgery. METHODS: Seventeen rabbit eyes were subjected to prolonged phacoemulsification within the anterior chamber, without manipulation or damage to other ocular structures. In nine eyes, a balanced salt ophthalmic solution was used as the phacoemulsification irrigation solution, and in eight eyes the solution plus 0.001 M ascorbic acid was used, all other parameters being identical between the two groups. Specular microscopy was performed in all eyes before and 1 week after surgery. The animals were then killed, and the corneas were examined histologically. RESULTS: There was no significant difference in preoperative endothelial cell counts between the two groups. Postoperative cell counts were reduced by 453.9 +/- 233.3 (SEM) cells/mm(2) in the solution-alone group versus 123.2 +/- 196.4 (SEM) cells/mm(2) in the solution-plus-ascorbic acid group, (P = 0.011). Corneal histology revealed a marked difference in endothelial cell morphology between the two groups. CONCLUSIONS: The addition of ascorbic acid to the irrigation solution significantly reduced the amount of endothelial cell loss during phacoemulsification by approximately 70%. This is thought to be due to the free-radical-scavenging properties of ascorbic acid. Further studies are warranted to find the optimal concentrations and combinations of free radical scavengers to be used in phacoemulsification irrigation solutions.