Astigmatism reduction: No-stitch 4.0 mm versus sutured 12.0 mm clear corneal incisions

Abstract

Purpose: To compare the effect on astigmatism of phacoemulsification using a 4.0 mm, no-stitch, clear corneal incision with that of extracapsular cataract extraction (ECCE) using a 12.0 mm, sutured, clear corneal incision. Setting: Augenklinik, Städtisches Klinikum Karlsruhe, Germany. Methods: The study comprised 211 patients who had cataract extraction and intraocular lens implantation through a superior clear corneal incision; 108 patients had phacoemulsification with a 4.0 mm no-stitch incision, and 103 had ECCE using a 12.0 mm sutured corneal incision. The main outcome measure was amount of astigmatism preoperatively and at 1 week and 3 and 6 months postoperatively. Corresponding medians (lower and upper quartiles) were evaluated. Results: Median surgically induced cylinder was 1.00 diopter (D) (range 0.56 to 1.50 D) in the 4.0 mm no-stitch incision group and 1.75 D (range 1.00 to 2.62 D) in the 12.0 mm sutured incision group. In eyes with preoperative with-the-rule astigmatism, astigmatism decreased from a median of 0.75 D (range 0.50 to 1.00 D) to 0.50 D (range 0 to 1.50 D) in the 4.0 mm incision group. The difference between preoperative and postoperative astigmatism in the 12.0 mm incision group was not statistically significant. Conclusion: Clear corneal cataract surgery leads to a predictable reduction in astigmatism when performed on the steeper axis with a small, no-stitch incision. Larger sutured incisions are not suitable for planned refractive changes but are still recommended in certain cases such as hard cataract and glaucoma.