Corneal Endothelial Protection of Ascorbic Acid against Free Radicals during Phacoemulsification

ABSTRACT

PURPOSE: To evaluate corneal endothelial protection effect of ascorbic acid (AA) at the most appropriate concentration, and determine the synergistic effect of glutathione in irrigation solution during phacoemulsification. METHODS: Phacoemulsification was performed in the anterior chamber of 30 rabbit eyes for 5 minutes without damage to other ocular structures. Thirty rabbit eyes were divided into 6 groups, of 5 eyes each, according to the following irrigation solutions in phacoemulsification. BSS(R) in group 1, BSS(R) with 1 mM AA in group 2, BSS Plus(R) in group 3, BSS Plus(R) with 0.1 mM AA in group 4, BSS Plus(R) with 1 mM AA in group 5 and BSS Plus(R) with 10 mM AA in group 6. Corneal endothelial loss was measured with specular microscopic photographies taken before and 1 week after surgery. RESULTS: Postoperatively endothelial counts were reduced by 592.0 +/- 100.0, 275.9 +/- 51.9, 658.2 +/- 107.1, 466.3 +/- 88.6, 259.3 +/- 61.6 and 451.6 +/- 63.7 (mean cells/mm2 +/- SD) in groups 1-6, respectively. Endothelial cells in group 2 were less reduced than in group 1 (P=0.009), but there was no difference between groups 2 and 5. Though the reduction of endothelial cells in groups 4, 5, and 6 were less than in group 3 (P<0.05), group 5 showed more significant endothelial protection effect than groups 4 and 6 (P=0.009, 0.009). CONCLUSIONS: AA in irrigation solution showed endothelial protection effect against free radicals during phacoemulsification, and 1 mM was the most effective concentration. Combination of glutathione with AA did not show any synergistic endothelial protection effect.