Endothelial cell density and contact lens-induced corneal swelling

To determine the relationships among endothelial morphometric variables and contact lens-induced corneal swelling in a homogeneous sample of adapted contact-lens wearers.

Fifteen male subjects ranging in age from 20 to 40 years, all adapted to daily wear of hydrogel lenses, wore uniform-thickness lenses (Dk/L = 5.78) under unilaterally patched eyes for 4 h. Unpatched fellow eyes served as controls. Central corneal thickness was measured with an optical pachometer. Central endothelial images were obtained with a Topcon SP-1000 Specular Microscope and analyzed by the Topcon IMAGEnet processing system. Thickness and morphometric data were collected on test and control eyes before and after the patching sessions.

A strong correlation (r = -0.795; p < 0.001) was found between central corneal swelling and endothelial-cell density. Correlations between swelling and the coefficient of variation in cell area (r = 0.502; p < 0.06) and between swelling and the percentage of six-sided cells (r = -0.200; p < 0.48) were not significant. Correlations among the morphometric variables were not significant. Differences in the morphometric variables between test and control eyes were not significant before or immediately after the patching sessions.

Endothelial-cell density is useful in explaining differences in corneal-swelling responses to closed-eye contact-lens wear among adapted wearers, whereas morphometric variables based on cell-size variability and shape are not.