Para-limbic relaxing incisions for reduction of astigmatism within the scope of catarct surgery

Abstract

Limbal relaxing incision (LRI) is an easy and safe procedure to reduce astigmatism. It should be clarified, whether the effect is discussed controversely, because the varying corneal diameter and consequently the varying LRI position was not considered. 56 patients aged 76 +/- 9 years with preoperative astigmatism of 1.6 D (0.6 to 7.0 D) underwent an almost astigmatically neutral cataract procedure (3.2 mm temporal clear corneal phacoemulsification with foldable lens implantation) and received independently from the given corneal diameter limbus related relaxing incisions of 80 degrees length and 0.6 mm depth. We performed the paired LRI in 4.5 mm, 5 mm and 5.5 mm distance from the corneal center on the steeper meridian. 4.3 months postoperatively we observed an astigmatic reduction of -1.0 D (-0.1 to -3.2 D) following LRI with a 9 mm optical zone, LRI with 10 mm diameter led to an astigmatic reduction of -0.4 D (-0.1 to -2.9 D) and LRI with 11 mm diameter were followed by an astigmatic reduction of -0.3 D (+0.5 to -1.1 D). Undercorrections were more frequently observed in younger patients, overcorrections more in elderly people. The application of three different kinds of limbus related relaxing incisions, with 4.5, 5 and 5.5 mm distance from the corneal center or 9, 10 and 11 mm optical zone respectively, corresponds to the variable anatomic situation of the limbus, therefore leading to nearly predictable data and explaining the divergent results of previous reports. The nearer the LRI is applied to the corneal center, the stronger is the relaxing effect.