Quantitative Assessment of Anterior Segment OCT Parameters and Their Association with Intraocular Pressure in Primary Angle-Closure Disease

Background/Objectives: Glaucoma represents a progressive optic neuropathy and is the leading cause of irreversible blindness worldwide. The disease is classified as primary angle-closure glaucoma (PACG) or as primary open-angle glaucoma (POAG) depending on the iridocorneal angle. Although gonioscopy remains the gold standard investigation, anterior segment optical coherence tomography (AS-OCT) may provide important data about these structures, offering a quantitative assessment of the angle. The purpose of this study is to evaluate AS-OCT parameters in patients with primary angle-closure disease (PACD). Methods: This retrospective exploratory study included 75 eyes from 60 patients with PACD, classified as primary-angle closure suspect (PACS), primary-angle closure (PAC) and PACG. Participants underwent comprehensive ophthalmic examination: best-corrected visual acuity (BCVA), gonioscopy, AS-OCT, optic nerve OCT, visual field examination, and specular microscopy. Associations between AS-OCT angle parameters, intraocular pressure (IOP), and ocular biometrics were assessed using correlation analyses with Benjamini–Hochberg correction for the primary analyses and generalized estimating equation (GEE) models to account for inter-eye correlation. Results: In the overall PACD cohort, AS-OCT angle parameters were inversely associated with IOP, with all primary correlations remaining significant after multiple-testing correction. GEE analysis confirmed significant associations for TISA500, AOD500, and AOD750. Exploratory analyses in the PACS, PAC and PACG subgroups were not significant after correction for multiple testing, while anterior segment biometric parameters showed expected intercorrelations. Conclusions: Quantitative angle parameters demonstrated robust inverse associations with IOP in the overall PACD cohort. These exploratory findings support the complementary role of AS-OCT in the PACD anatomical evaluation and warrant confirmation in larger prospective studies to determine their clinical and prognostic relevance.