Induced astigmatism following small incision cataract surgery combined with trabeculectomy

The combination of phacoemulsification and implantation of foldable intraocular lenses through a small incision with a trabeculectomy is increasingly preferred in glaucoma patients with coexisting cataract. Small incisions induce less astigmatism and thereby enhance visual recovery. This study should clarify if this benefit of small incision cataract surgery is preserved when combined with a trabeculectomy. Thirty-five eyes were included in this study. Preoperative astigmatism measurements were compared with those obtained one month and one year postoperatively. Vector analysis was performed. A series of 30 cases which underwent small incision cataract surgery alone were used as a control group. One month postoperatively the eyes undergoing the combined procedure showed about the same with-the-rule astigmatic peak (mean: +0.32 dpt.) as the control group eyes (mean: +0.26 dpt.; p > 0.05). One year postoperatively both groups showed the same against-the-rule astigmatic shift (mean: -0.28 dpt.; p > 0.05). In conclusion, patients undergoing small incision cataract surgery combined with trabeculectomy showed a small amount of surgically induced astigmatism. When compared with patients which underwent small incision cataract surgery alone, the difference in astigmatic changes was found to be statistically not significant.