The Effect of Contact Lens Wear on the Central and Peripheral Corneal Endothelium

Purpose. To compare central and peripheral corneal endothelial cell morphometry in normal subjects and long-term contact lens wearers. Methods. Endothelial cell density (ECD), coefficient of variation of cell area (CV), and percentage of six-sided cells were measured by contact specular microscopy in the corneal center and temporal periphery of both eyes of 43 long-term contact lens wearers and in 84 normal subjects who had never worn contact lenses. The latter group included 43 age- and sex-matched controls for the contact lens wearers. ECDs were corrected for magnification changes due to corneal thickness. Results. Central ECD (2,723 +/- 366 cells/mm(2), mean +/- SD) was significantly higher than peripheral ECD (2,646 +/- 394 cells/mm(2)) for the normal group (p = 0.01) but not for the contact lens wear group (2,855 i:I 28 cells/mm(2) central, 2,844 +/- 494 cells/mm(2) peripheral, p = 0.84). Peripheral CV was significantly higher than central for normal subjects and contact lens wearers and was significantly higher in both center and periphery in contact lens wearers than in controls. Central percentage of six-sided cells was significantly higher than peripheral for normal subjects and contact lens wearers and was lower in both center and periphery in contact lens wearers than in controls. Conclusions. Central ECD was significantly higher by 3% than peripheral ECD in normal subjects, but not in contact lens wearers. The results suggest that contact lens wear causes a mild redistribution of endothelial cells from the central to the peripheral cornea. A reversal of this redistribution after contact lens wear is discontinued for refractive surgery could mask mild central endothelial damage from the refractive procedure.