Corneal endothelial response to refitting polymethyl methacrylate wearers with rigid gas-permeable lenses

Thirteen persons who had been wearing only polymethyl methacrylate (PMMA) contact lenses for 3 years or more were switched to a contact lens material providing greater oxygen transmissibility (Itafocon A) while keeping other contact lens parameters the same. Monitoring of corneal endothelial cells during the first 4 months of the rigid gas-permeable (RGP) lens daily wear showed no significant change in the coefficient of variation of cell area (polymegethism) or percentage of hexagonal endothelial cells at the end of 4 months. However, paired data did show a small, but significant, decrease in cell density at the end of 4 months (3174 to 2908 cells/mm2). The results suggest that a sudden shift in the general corneal environment toward more available oxygen may have some early effect on endothelial cell density, but changes in endothelial cell size variation and form are not determined.