Ocular biometry in the subtypes of angle closure: an anterior segment optical coherence tomography study

Abstract

Purpose: To evaluate ocular biometric parameters in different subtypes of angle-closure disease in the Iranian population and compare them with normal eyes.

Design: Prospective, cross-sectional.

Methods: 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 500 μm from the scleral spur (AOD500, TISA-500), anterior chamber angle, lens vault, lens thickness, anterior chamber depth (ACD), and lens position.

Results: 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.

Conclusions: 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.