Effects of long-term contact lens wear on the corneal endothelium

Abstract

Purpose: To analyze the long-term effects of soft and hard (PMMA) contact lenses (CL) on the human corneal endothelium. Methods: One hundred and one contact lens wearers with ≤ 10 years' wearing time and 50 healthy control subjects were examined with specular microscope. Results: The mean corneal endothelial cell densities of the CL wearers (2846 cells/mm2) and of the control eyes (2940 cells/mm2) differed by 94 cells/mm2 (p < 0.05). The mean values for the coefficient of variation (CV) differed significantly (p < 0.0001); for all CL wearers: mean CV = 0.31, vs. for controls: 0.22. The mean endothelial cell density of the eyes exposed to CL wear for more than 25 years (30 eyes) was 2575 cells/mm2 (mean CV: 0.36). Rather low densities ( < 2000 cells/mm2) were observed in 16 eyes of the CL group (8%). Cell densities less than 2500 cells/mm2 were observed in a total of 41 eyes (20%) in the CL group, whereas in the control group (100 eyes) all of the subjects, except one, had cell densities of more than 2500 cells/mm2 in both eyes. Conclusion: A subgroup of PMMA as well as soft contact lens wearers react not only with high pleomorphism and polymegethism but also with a decrease in endothelial cell density.