Protective effects of dispersive viscoelastics on corneal endothelial damage in a toxic anterior segment syndrome animal model

PURPOSE. We evaluated whether viscoelastics have protective effects on the corneal endothelial cell damage in a toxic anterior segment syndrome (TASS) animal model depending on the types of viscoelastics. METHODS. ATASS animal model was established with an injection of 0.1 mL o-phthaldehyde solution (0.14%) into the anterior chamber of New Zealand white rabbits. One of two different viscoelastics, 1% sodium hyaluronate (cohesive group) or a 1:3 mixture of 4% chondroitin sulfate and 3% sodium hyaluronate (dispersive group), was injected into the anterior chamber. After five minutes, it was removed using a manual I/A instrument, and then 0.1 mL of o-phthaldehyde solution (0.14%) was injected into the anterior chamber. Damage to corneal endothelial cells was compared between the two groups. RESULTS. The corneal thickness increased quickly in both groups after the disinfectant injection. However, the dispersive group showed relatively mild corneal edema compared to the cohesive group. The mean corneal haze score in the dispersive group also was lower than that of the cohesive group. These partial protective effects of the dispersive viscoelastic were demonstrated by the different findings of a live/dead cell assay, TUNEL staining, and scanning electron microscopy between the two groups. CONCLUSIONS. The TASS animal model seems to be a useful means to evaluate corneal endothelial cell damage caused by toxic substances to find ways to protect or reduce endothelial cell damage. Dispersive viscoelastics were shown to have partial protective effects against corneal endothelial cell damage caused by a toxic disinfectant.