Abstract:

 Objective  To measure and evaluate ocular anterior segment static parameters and the dynamic changes in anterior chamber (AC) morphology under light and dark condition respectively in fellow eyes of acute angle-closure patients, the eyes with asymptomatic narrow angles(primary angle-closure suspects, PACS)  and normal open-angle eyes using anterior segment optical coherence tomography (AS-OCT). Design Comparative case series. Participants 36 fellow eyes of patients with acute angle closure; 120 PACS eyes; and 144 normal open-angle eyes from   Peking University Shenzhen Hospital and Zhejiang Hospital. Methods All the participants were imaged under light and dark conditions using AS-OCT. Main Outcome Measures  The anterior segment data from AS-OCT under light and dark conditions, include pupil diameter (PD), iris area (IA), angle open distance (AOD), anterior chamber angle (ACA), trabecular iris area (TISA), angle recess area (ArA). Results  The static anterior segment anatomic parameters did not differ significantly between the fellow eyes and the PACS eyes. When going from light to dark, the change of pupil diameter was more significant in the normal eyes than the fellow eyes and the PACS eyes. The mean iris area increased significantly in the fellow eyes (+5.83%), whereas it decreased in most PACS eyes (-3.50%), but not as significant as normal open angle eyes (-12.50%, P=0.004). The change rate of IA (IA%) and IA% per mm2 PD change (ΔIA%/ΔPD) differ significantly between the fellow eyes and the PACS eyes (P=0.036). The AOD, ACA, TISA and ARA decrease when going from light to dark, but the variations did not differ significantly between the two groups. Conclusion The static parameters alone had poor predictive power to identify eyes that will have the angle closure in future. The dynamic change of iris area in the fellow eyes and PACS eyes were significantly different. The abnormal dynamic behavior of the iris occurring in anatomically may predisposed eyes is a high risk of angle closure. (Ophthalmol CHN, 2017, 26: 238-243)

Key words: glaucoma, angle closure, anterior , segment optical coherence tomography