The Effect of Corneal Edema on Corneal Topography

Nam, Sang Kil; Kim, Keun Tae; Kim, Ki San

Abstract

To evaluate the changes in corneal topography following contact lens-induced corneal edema, sixty eyes of 30 patients that had never worn contact lenses were examined. A contact lens with very low oxygen transmissibility was placed over each cornea to induce corneal edema. The changes in corneal thickness, refraction, keratometry and topography were measured before and after subjects had been wearing hydrogel contact lens for 2 hours. The mean change in corneal thickness was 43.60 +/- 7.87 microgram from 542.90 +/- 22.89 microgram before contact lens wear to 586.50 +/- 23.19 microgram after contact lens wear (p=0.0000). Refracive change in vertical meridian was 0.1D increasing from -4.09D to -4.19D after contact lens wearing (p=0.0002), and there also was a small change in refractive errors in horizontal meridian decreasing from -3.45D to -3.34D (p=0.0000). There was a tendency toward with-the-astigmatism, because corneal curvature and Sim K value also increased in vertical meridian and decreased in horizontal meridian. These results suggest that contact lens-induced corneal edema may influence the corneal configuration in some degree, however, these changes does not seem to be clinically significant.