Effect of H ₂ O ₂ Concentration and Exposure Time on Stromal Swelling

The corneal epithelium can be affected adversely by some preservatives used in contact lens solutions. To test the effect of H 2 O 2 at the epithelial surface, the rabbit cornea was perfused with various concentrations of H 2 O 2 , and the effect on stromal and Anterior Bright Band (ABB) thickness measured for 150 min. The study compares stromal swelling and ABB swelling for a single 10‐min pulse with that for a 150‐min sustained dose. With the 10‐min pulse dose there was no significant swelling up to 235 ppm H 2 O 2 , the highest dose tested. With the sustained dose, significant stromal swelling began between 72 and 153 ppm H 2 O 2 . These results indicate that residual H 2 O 2 present at the epithelial surface after neutralization in current contact lens disinfection systems does not have a high enough concentration to affect corneal function adversely.