Protective effect of free-radical scavengers on corneal endothelial damage in phacoemulsification

PURPOSE: To examine the role of the water-soluble antioxiclants glutathione and ascorbic acid in the irrigating solution on corneal enclothelial cells following exposure to high-intensity ultrasound energy. SETTING: Goldschleger Eye Research Institute, Sheba Medical Center, Tel-Aviv University, Tel Aviv, Israel. METHODS: Thirty-two rabbit eyes were subjected to prolonged exposure to the phacoemulsification device in the anterior chamber. The eyes were divided into 4 groups that differed only in the composition of the irrigating solution applied to the eyes: balanced salt solution (BSS) BSS Plus BSS containing additional soluble components including glutathione, BSS with 10(-3) M of oxidized glutathione (GSSG), and BSS with 10(-2) M of ascorbic acid. Specular microscopy was performed preoperatively and 1 week after surgery. RESULTS: The BSS group exhibited the highest enclothelial cell loss (19.3%), followed by the BSS Plus group (10.6%), the GSSG group (5.2%), and the ascorbic acid group (0.9%). An overall difference was found between the groups (F = 11.046, P < .0001), and all groups demonstrated a statistically significant difference from the control BSS group (P < .02, P =.001, and P < .0001, respectively). CONCLUSIONS: Damage to the cornea is largely due to the free radicals generated by high-intensity ultrasound energy during phacoemulsification. Adding the antioxidants ascorbic acid and GSSG to the irrigation solution significantly reduced the enclothelial corneal cell damage. Ascorbic acid in the concentration of 10-2 M had the highest protective effect; thus, it should be evaluated for clinical use.