Effect of temporal and nasal unsutured limbal tunnel incisions on induced astigmatism after phacoemulsification

Purpose: To compare the surgically induced corneal astigmatism after unsutured temporal and nasal unsutured limbal tunnel incisions. Setting: Departments of Ophthalmology, Marienhospital, Aachen, and Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. Methods: In a prospective clinical study, 42 eyes of 21 patients with a mean age of 75.1 years had phacoemulsification and implantation of a foldable hydrophobic acrylic intraocular lens using a 3.6 to 3.8 mm unsutured limbal tunnel incision. The right eye always received a temporal incision and the left eye, a nasal incision. Computerized videokeratography was performed preoperatively and 2 weeks and 6 months postoperatively. Surgically induced astigmatism was calculated by vector analysis using the Holladay-Cravy-Koch formula. The 2 groups were compared using a paired Wilcoxon test. Results: The mean surgically induced corneal astigmatism in the temporal incision group was 0.62 diopters (D) ± 0.48 (SD) 2 weeks postoperatively and 0.47 ± 0.32 D at 6 months and in the nasal incision group, 1.55 ± 0.84 D and 1.05 ± 0.57 D, respectively. The difference between the groups was statistically significant (P < .05). Conclusions: There was a highly statistically significant difference in surgically induced corneal astigmatism after temporal and nasal unsutured limbal tunnel incisions. The degree of induced astigmatism and the difference between the temporal and the nasal incisions decreased over time. A nasal tunnel incision is not appropriate for astigmatism-neutral surgery.