Corneal topographic changes after frown and straight sclerocorneal incisions

PURPOSE: To compare the corneal topographic changes following cataract surgery with two types of sclerocorneal tunnel incisions for implantation of 6.0 mm optic poly(methyl methacrylate) intraocular lenses. SETTING: University Eye Hospital, Vienna, Austria. METHODS: This prospective, unmasked, and unrandomized study comprised 48 otherwise healthy eyes scheduled for cataract surgery. A 4.5 mm sutureless frown incision was made in 22 eyes and a 6.0 mm straight sclerocorneal incision with a horizontal 10-0 nylon infinity suture in 26 eyes. Preoperatively and 1 week and 1 and 3 months postoperatively, corneal topography was recorded by the TMS-1 computer-assisted videokeratoscope (Computed Anatomy, Inc.). The data were evaluated by batch-by-batch analyses of the paired differences between the records. The significance of topographic changes was calculated by paired Wilcoxon tests; group comparisons were made using Wilcoxon tests. RESULTS: In both groups, horizontal steepening and lower corneal flattening were consistently 0.4 diopter (D). Upper peripheral corneal flattening at 1 week and 1 and 3 months postoperatively was 0.7, 0.7, and 0.7 D, respectively, in the straight-incision group and 0.7, 0.4, and 0.3 D, respectively, in the frown-incision group. Vertical flattening and horizontal steepening were significant in both groups (P < .01). Group comparisons revealed significant differences in only 15 of 225 areas (P < .05). CONCLUSION: There were no major differences between the two incision groups in surgically induced topographic changes.