Wide-field specular microscopy and computer-assisted morphometry were performed on 20 aphakic eyes in 16 patients who had worn a high-water content hydrogel contact lens on an extended wear basis for at least 12 months (mean, 28 months) following intracapsular cataract extraction. When compared with 22 non-lens-wearing aphakic eyes matched for age and postoperative period, the endothelial cell changes in the above patients included a significantly higher coefficient of variation in cell area (polymegathism) and a marked reduction in the frequency of hexagonal cells (pleomorphism) without any significant difference in cell density. Although the clinical significance of these endothelial changes remains unclear, they may indicate hypoxic stress to the corneal endothelium or be an early sign of ongoing cell loss.