Study Design: Prospective case series. Purpose: To determine if narrower-angle status and anterior segment optical coherence tomography (AS-OCT) parameters predict intraocular pressure (IOP) reduction after cataract surgery in primary open-angle glaucoma (POAG) patients. Methods: 63 eyes from 45 POAG patients without peripheral anterior synechiae underwent cataract surgery. Preoperative gonioscopy and AS-OCT were performed. IOP was reassessed at 1 year. Mixed-effects regression accounted for inter-eye correlation and confounders. Results: IOP dropped more in the narrower-angle group (3.8 ± 3 mm Hg, 22.4%) vs wide-angle group (2.7 ± 2.9 mm Hg, 13%) by gonioscopy (P = 0.02). AOD500-based classification showed similar trends (P = 0.031). Greater IOP reduction correlated with increased iris thickness, area, and lens vault (P < 0.05). Conclusion: POAG eyes with narrower angles had greater IOP reduction after cataract surgery. AS-OCT parameters may help predict surgical benefit. Clinical Significance: AS-OCT and angle analysis may identify POAG patients likely to gain IOP control from cataract surgery, shifting its role from vision correction alone to a targeted glaucoma strategy — offering a window into personalized surgical decision-making.

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