THE LONG-TERM EFFECTS OF POLYMETHYLMETHACRYLATE CONTACT-LENS WEAR ON THE CORNEAL ENDOTHELIUM

Purpose: The purpose of this study is to determine the long-term effec ts of polymethylmethacrylate (PMMA) contact lens wear on the corneal e ndothelium. The authors had noted previously advanced polymegethism an d decreased cell densities in a few long-term PMMA contact lens wearer s. They evaluated a large group of such lens wearers to determine the prevalence of polymegethism and reduced endothelial cell density withi n this lens-wearing population. Methods: The authors examined the morp hologic characteristics of the corneal endothelium in 162 PMMA contact lens wearers or age-matched controls. Eighty-one subjects had worn co ntact lenses for more than 20 years. Results: Patients showed advanced polymegethism and pleomorphism compared with controls. Mean cell dens ity 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/mm(2) compar ed 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%). Conclusion : This study is unique, in that it notes a subgroup of PMMA contact le ns wearers who are more susceptible to significant morphometric change s and reduced endothelial cell densities with long-term contact lens u se.