Effect of soft lens power on peripheral corneal edema.

The effect of soft lens design (lathe cut, spun cast) and power (-0.75 to -9.00 D) on central and peripheral corneal swelling was analyzed by measuring the change in corneal thickness after 3 h of eye closure and at mid-day during extended wear. Peripheral swelling was less than central for both lathe cut- and spun cast-type lenses. Significant correlations were found between spun cast lens power and central (r = +0.48) or peripheral (r = +0.32) swelling during eye closure. Small differences in swelling occurred with different power lathe cut lenses (r = -0.19). Correlations of mid-day (open eye) central corneal swelling with lens power were significant for both the spun cast (r = +0.43) and lathe cut (r = -0.53) lenses. However, correlation of peripheral swelling with power was weak. These results indicate that significant lateral diffusion of oxygen and/or epithelial metabolites may be occurring in the cornea between areas of high and low oxygen tension.