Limbal relaxing incisions using a reference point and corneal topography for intraoperative identification of the steepest meridian.

摘要

PURPOSE: To examine the efficacy and safety of topography-based limbal relaxing incision (LRI) surgery. METHODS: Forty-four eyes of 36 consecutive patients who underwent cataract surgery more than 1 month previously, had refractive against-the-rule astigmatism of >/=2.00 diopters (D), and were scheduled to undergo LRI surgery were enrolled in the study. Patients were randomized into two groups-a topography-based LRI group (19 eyes of 14 patients) and a conventional LRI group (25 eyes of 22 patients). The topography-based LRI procedure comprised 3 steps: placing a mark on the cornea and conjunctiva, identifying this mark in the topographic image, and performing LRI based on the location of the mark. In the conventional LRI group, the horizontal meridian was marked under a slit lamp and LRIs were made based on the position of the horizontal mark. RESULTS: Corneal astigmatism in the topography-based LRI group before and 1 month after surgery was 2.03+/-0.92 D and 1.33+/-0.69 D, respectively (P=.014). Corneal astigmatism in the conventional LRI group before and 1 month after surgery was 2.36+/-0.77 D and 0.93+/-0.70 D, respectively (P<.0001). Fourier harmonic analysis of the topography data demonstrated that regular astigmatism was significantly decreased in the two groups. The mean regular astigmatism was not significantly different before and after LRI between groups, whereas the variances (mean of the deviation squared from its mean) of regular astigmatism were significantly different between groups 1 month after LRI. CONCLUSIONS: Compared with conventional LRI surgery, a topography-based procedure may reduce the deviation of the effect of LRIs.