Effect of anterior and posterior corneal surface irregularity on vision after Descemet-stripping endothelial keratoplasty

Abstract

PURPOSE: To evaluate irregularity of the anterior and posterior cornea before and after Descemet-stripping endothelial keratoplasty (DSEK) and its effect on visual acuity. SETTING: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. METHODS: Corneal data were acquired using a rotating Scheimpflug camera before and 1 month and 3 months after DSEK. Anterior and posterior corneal elevation data were decomposed into a set of Zernike polynomials up to the 8th order within a 4.0 mm diameter region. Total higher-order root mean square (HO-RMS) and RMS from the 3rd to 8th order were calculated. The effects of anterior and posterior surface irregularity on visual acuity were evaluated. RESULTS: This clinical study comprised 13 consecutive eyes of 12 bullous keratopathy patients. The mean best corrected visual acuity (BCVA) was 1.11 logMAR +/- 0.5 (SD) preoperatively, 0.49 +/- 0.49 logMAR 1 month postoperatively, and 0.27 +/- 0.32 logMAR at 3 months. The HO-RMS of the anterior surface 1 month (P = .040) and 3 months (P = .048) postoperatively was significantly lower than preoperatively. There were no significant differences in posterior surface HO-RMS between preoperatively and 1 month (P = .45) and 3 months (P = .054). The postoperative BCVA was significantly correlated with HO-RMS (P<.001), but not with posterior surface HO-RMS, at 3 months (P = .354). CONCLUSION: Postoperative BCVA correlated with irregularity of the anterior surface but not the posterior surface. In addition to corneal transparency, regularity of the anterior surface is an important factor in visual acuity after DSEK.