Low Iris and Anterior Chamber Volume Associated with Deepening after Laser Peripheral Iridotomy in Primary Angle Closure Suspects

Purpose: To evaluate the associa on between baseline ocular variables and the opening of the anterior chamber angle by laser peripheral iridotomy (LPI) in primary angle closure suspects (PACS) using a new Fourier-domain swept-source anterior segment op cal coherence tomography (FD-ASOCT). Method: Sixty-six PACS eyes of 41 individuals were included in this prospec ve interven onal case series. An FD-ASOCT (Casia SS-1000 OCT; Tomey, Nagoya, Japan) was used to measure biometric baseline variables and at one month a er the LPI. Paired t-test was used to compare the difference between pre-and post-LPI measurements. Mul variate regression analysis was used to test for an associa on between baseline iris thickness and volume, anterior chamber depth and volume, and lens vault with a widening of the angle a er an LPI. Results: The mean age of par cipants was 58.6 ± 8.7 years, 682% of whom were female. The angle opening distance, recess area and trabecular iris surface area at 500 microns increased by 48 to 73% (all p<0.001). Lens vault and iris volume did not change. A low anterior chamber volume and low iris volume were associated with angle greater deepening by LPI. Conclusion : Eyes with a shallow anterior chamber and thinner irises are more likely to experience angle opening from a LPI.