The Long-term Effects of Polymethylmethacrylate Contact Lens Wear on the Corneal Endothelium

Abstract

The purpose of this study is to determine the long-term effects of polymethylmethacrylate (PMMA) contact lens wear on the corneal endothelium. The authors had noted previously advanced polymegethism and decreased cell densities in a few long-term PMMA contact lens wearers. They evaluated a large group of such lens wearers to determine the prevalence of polymegethism and reduced endothelial cell density within this lens-wearing population. The authors examined the morphologic characteristics of the corneal endothelium in 162 PMMA contact lens wearers or age-matched controls. Eighty-one subjects had worn contact lenses for more than 20 years. Patients showed advanced polymegethism and pleomorphism compared with controls. Mean cell density in the contact lens-wearing group was not different from controls, but a significantly greater percentage of contact lens wearers (11%, 9 of 81 patients) had cell densities less than 2000 cells/mm2 compared with controls (2.5%, 2 of 81 patients), and were also significantly more likely to have severe polymegethism (coefficient of variation, > 0.60) and severe pleomorphism (frequency of hexagons < 40%). This study is unique, in that it notes a subgroup of PMMA contact lens wearers who are more susceptible to significant morphometric changes and reduced endothelial cell densities with long-term contact lens use.