Baseline Anterior Segment Parameters Associated with the Long-term Outcome of Laser Peripheral Iridotomy

Abstract

Purpose: To investigate the baseline anterior segment (AS) parameters determined by AS optical coherence tomography (AS OCT) in the prediction of long-term outcome of laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS) eyesMethods: Participants were imaged at pre-LPI and at 2 weeks and 3 years post-LPI using AS OCT. Based on these images, anterior chamber depth (ACD), iris curvature (IC), anterior chamber width (ACW), iris thickness at 750 µm from the scleral spur (IT750), lens vault (LV), and iris area (IA) were estimated using the Image J software (version 1.46). Proportional change (%) in angle opening distance at 750 µm from the scleral spur (AOD750) was used as an outcome measure for LPI. Univariate and multivariate regression analyses were performed to evaluate baseline AS parameters associated with changes in AOD750.Results: A total of 39 PACS eyes were included. At 2 weeks post-LPI, thinner IT750 (p = 0.006) and less AOD750 (p < 0.001) at baseline were related to a greater AOD750 change. When assessed at 3 years post-LPI, thinner IT750 (p = 0.039) and less AOD750 (p = 0.003) at baseline were associated with a greater AOD750 change.Conclusions: Thin peripheral iris and less AOD750 at baseline were associated with greater changes in longitudinal assessment after LPI. PACS eyes with thick peripheral iris at baseline showed less AOD750 change at both early and late follow up after LPI; therefore, such eyes should be followed with caution despite successful LPI.