Strategies for minimizing the ocular effects of extended contact lens wear--a statistical analysis.

In a study reported recently, the effects of long-term extended wear of soft contact lenses on the human cornea were found to include epithelial thinning, a reduction in epithelial oxygen uptake, induction of epithelial microcysts, stromal thinning, and an increase in endothelial polymegathism. A multiple regression analysis was performed on data from this study to identify lens or patient characteristics associated with these effects. Although generalization to the population of conclusions based on associations identified using a small sample should be treated with caution, results from this analysis suggest that lens-induced effects on the cornea may be minimized by fitting lenses that are thinner and more mobile, and by encouraging more frequent lens removal and replacement. Patients with thinner corneas and with high endothelial cell density and low polymegathism before commencing lens wear tended to show fewer effects from extended lens wear.