Comparative study of corneal topographic changes after 3.0 mm beveled and hinged clear corneal incisions

PURPOSE: To compare the corneal topographic changes after cataract surgery using 2 types of clear corneal incisions (CCIs). SETTING: Department of Ophthalmology, University of Vienna, Austria. METHODS: This prospective, unmasked, nonrandomized study comprised 64 eyes scheduled for cataract surgery; 29 eyes received a temporal sutureless 3.0 mm corneal beveled CCI and 35 eyes, a temporal sutureless 3.0 mm hinged CCI. Preoperatively and 1 week, 1 and 3 months, and 1 year postoperatively, corneal topography was recorded by computer-assisted videokeratoscopy (TMS-1, Computed Anatomy, Inc.). Data were evaluated by batch-by-batch analyses of the paired differences between these records. The significance of topographic changes was calculated by paired Wilcoxon tests, and group comparisons were made using Wilcoxon tests. RESULTS: In both groups, there was statistically significant horizontal flattening and lower corneal steepening (P < .01). The horizontal flattening decreased between 1 week and 1 year, from -0.6 to -0.3 diopter (D) in the beveled-incision group and -0.7 to -0.4 D in the hinged-incision group. Vertical steepening was significant in the lower corneal region and decreased between 1 week and 1 year, from 0.3 to 0.2 D. Group comparisons revealed significant differences in an oblique lower temporal semimeridian, with 0.1 to 0.3 D more steepening after the hinged incision than after the beveled incision (P < .05). CONCLUSION: There were only minimal differences between beveled and hinged CCIs in surgically induced corneal shape changes.