Induced astigmatism in small incision cataract surgery.

The use of smaller cataract incisions is thought to induce less astigmatism, resulting in a more stable refraction. I analyzed the astigmatic changes in 99 cataract/intraocular lens patients with 4.0 mm incisions. Preoperative keratometry measurements were compared with those obtained one week, one month, and three months postoperatively. These changes, analyzed by vector analysis, revealed 0.13 D of induced with-the-rule astigmatism at one week, degrading to 0.22 D of against-the-rule at three months. This compares favorably with previously reported results of 6.0 mm and 10.0 mm incisions. This low amount of induced cylinder and rapid stabilization of the wound confirms an advantage of small incision surgery.