Specular microscopy of unilateral hard contact lens wearers.

The effects of long term wear of PMMA contact lenses on the corneal endothelium used on a daily wear basis were determined by examining 8 patients who had been prescribed lenses in one eye only. The patients excluded unilateral aphakes. It was found that a significant reduction in the cell density and a change in the cell size and shape was induced by PMMA lenses. These changes reflect an endothelial metabolic stress and emphasize the need to find newer lens materials that are more oxygen permeable and produce little interference with the corneal metabolism.