Ocular Biometry in the Subtypes of Angle Closure: An Anterior Segment Optical Coherence Tomography Study

Abstract

To evaluate ocular biometric parameters in different subtypes of angle-closure disease in the Iranian population and compare them with normal eyes. Prospective, cross-sectional. In this clinic-based study, 189 eyes of 154 patients consisting of 40 acute angle-closure glaucoma (AACG) eyes, 40 fellow eyes of AACG, 42 chronic angle-closure glaucoma (CACG) eyes, 40 primary angle-closure suspect (PACS) eyes, and 27 normal eyes underwent complete examination including gonioscopy, A-scan biometry, and anterior segment optical coherence tomography. Only 1 eye of CACG, PACS, and control subjects were selected. Main outcome measures included angle opening distance and trabeculo-iris space area at 500μm from the scleral spur (AOD500, TISA-500), anterior chamber angle, lens vault, lens thickness, anterior chamber depth (ACD), and lens position. Anterior chamber angle, AOD500, TISA500, ACD, and lens position were less and lens thickness and lens vault were greater in angle-closure than open-angle eyes. ACD was less in AACG than CACG and PACS (P < .001). It was also less in fellow eyes than PACS eyes (P= .04). Lens vault was highest in AACG eyes, followed by fellow eyes, PACS, and CACG. It was significantly more in AACG eyes than CACG and PACS eyes (P < .001 and P= .007, respectively). No difference was observed between AACG and fellow eyes. The anterior segment was crowded in closed-angle compared to open-angle eyes. Higher lens vault may play a role in the development of an acute attack of angle closure.