Characteristics of successful filtering blebs at 1year after trabeculectomy using swept-source three-dimensional anterior segment optical coherence tomography.

Abstract

To identify the cross-sectional characteristics of filtering blebs associated with intraocular pressure (IOP) control at 1year after trabeculectomy with a square scleral flap and a fornix-based conjunctival flap. A retrospective consecutive case series study was conducted. Eighty-four eyes of 79 patients who had undergone primary trabeculectomy were included. Surgical success was defined as IOP ≤15mmHg and a >20% reduction in IOP without glaucoma medication and without additional glaucoma surgery at 1year after trabeculectomy. The subjects were classified into two groups according to whether surgery was successful or unsuccessful. Filtering blebs were examined using swept-source three-dimensional anterior segment optical coherence tomography and evaluated for the following quantitative parameters: maximum bleb height, maximum bleb wall thickness, and ratio of hypo-reflective space of the bleb wall. Sixty-six eyes were determined to be successful and 18 eyes unsuccessful. Univariate analysis showed significant differences between the two groups regarding bleb height (P<0.001), bleb wall thickness (P=0.011), and ratio of hypo-reflective space of the bleb wall (P=0.002). Multivariate logistic regression analysis confirmed that the bleb height was significantly associated with success in trabeculectomy [odds ratio 13.996 (95% confidence interval 1.184-165.420); P=0.036]. A tall bleb with a thick hypo-reflective wall may be a feature of the well-functioning bleb.