Ascorbic Acid Is Cytotoxic to Dividing Human Tenon's Capsule Fibroblasts: A Possible Contributing Factor in Glaucoma Filtration Surgery Success

Successful glaucoma filtration surgery depends on the incomplete healing of the surgical wound, with formation of a filtration bleb. In most other tissues, however, complete healing is the rule. I have explored the possibility that the high concentration of ascorbic acid normally present in aqueous humor inhibits wound healing after filtration surgery. At the concentration normally present in aqueous humor (1.1 mmol/L), ascorbic acid decreased the plating efficiency of cell suspensions of human Tenon's capsule fibroblasts by a mean (±SD) of 40%±10%. When added to low-density monolayer cultures of fibroblasts, ascorbic acid decreased the cell number by 90%±5%, an effect that was completely prevented by catalase. When added to confluent cultures, the cell number was decreased by only 14%±2%. If ascorbic acid has similar effects on fibroblasts in vivo, it may contribute to the incomplete wound healing that characterizes successful glaucoma surgery.