Residual H2O2 compromises deswelling function of in vivo rabbit cornea

The purpose of the study was to investigate the effect of H2O2 on corneal swelling, corneal deswelling and to determine the concentration of H2O2 in the aqueous humor. Four types of experiments were performed using the rabbit eye. 1. Central corneal thickness (CCT) measurements after instillation of H2O2 into the cul-de-sac and after wearing H2O2 soaked soft contact lenses (SLC) for 2 h using 60 ppm, 100 ppm and 300 ppm H2O2. 2. Measurement of corneal deswelling induced by wearing SCL and closed eye for 2 h. 3. Determining the H2O2 in the aqueous humor one h after instillation of H2O2 into the cul-de-sac. CCT increases of 7.5% and 10.7% were found after the instillation of 100 ppm and 300 ppm H2O2 into the cul-de-sac. After wearing H2O2 soaked SCLs, CCT increased 4.6% and 5.8%, respectively. The H2O2 in the aqueous humor was 0.087 mM or a 160% increase after using 300 ppm H2O2. The increase in CCT and interference with the deswelling process is interpreted as a toxic effect on the cornea and an interference with the normal dehydration function of the endothelial pump.