Predictors of angle widening after laser iridotomy in Chinese patients with primary angle-closure suspect using ultrasound biomicroscopy

To assess the predictive value of baseline parameters of ultrasound biomicroscopy (UBM) for angle widening after prophylactic laser peripheral iridotomy (LPI) in patients with primary angle-closure suspect (PACS). Angle-opening distance (AOD), trabecular iris angle (TIA), iris thickness, trabecular-ciliary process angle, and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI. Iris convexity (IC), iris insertion, angulation, and ciliary body (CB) size and position were graded. Uni- and multivariate regression analyses were used to determine factors predicting the change in AOD (ΔAOD500, calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC. In 94 eyes of 94 patients with PACS, LPI led to angle widening with increases in AOD500 and TIA (