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

To compare the corneal topographic changes after cataract surgery using 2 types of clear corneal incisions (CCIs).

Department of Ophthalmology, University of Vienna, Austria.

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.

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).

There were only minimal differences between beveled and hinged CCIs in surgically induced corneal shape changes.