The Effect of Trabeculectomy on Astigmatism

PURPOSE:To investigate the change in corneal astigmatism after trabeculectomy. PATIENTS AND METHODS:Between January and April 2012, patients who underwent a primary trabeculectomy were enrolled in this prospective study. We measured the visual acuity, automated keratorefractometry, and the intraocular pressure preoperatively and postoperatively at 1, 3, and 6 months. Changes in astigmatism were quantified using the vector analysis described by Cravy. A Friedman test and a linear model for longitudinal measures were used to compare changes in the refraction and the intraocular pressure. A binomial test was used to compare the proportion of eyes with a shift in astigmatism with or against-the-rule. RESULTS:A total of 47 eyes (47/48 patients) were included for analysis. The mean (±SD) intraocular pressure decreased from 17.5±5.4 mmHg preoperatively to 9.8±4.0 mmHg after 6 months (P