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

Purpose: To examine the role of the water-soluble antioxidants glutathione and ascorbic acid in the irrigating solution on corneal endothelial 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 endothelial 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 endothelial 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.