Comparison of anterior segment parameters between the acute primary angle closure eye and the fellow eye

PURPOSE. To investigate features of the anterior segment (AS) of the affected eye compared to the fellow eye within the same patient in acute primary angle closure (APAC). METHODS. Thirty-six patients with unilateral APAC were imaged with AS optical coherence tomography (OCT) before medical or laser treatment for the acute attack. Anterior chamber depth (ACD), iris curvature (IC), iris thickness at 750 μm from the scleral spur (IT₇₅₀), lens vault (LV), anterior chamber area (ACA), and iris area were estimated by using ImageJ software (version 1.46). Conditional logistic regression analysis was performed to find the associated factors with the prediction of APAC. RESULTS. When compared to fellow eyes, affected eyes showed significantly shallower ACD (1.90 ± 0.24 and 1.55 ± 0.30 mm, respectively; P < 0.001), smaller ACA (12.96 ± 2.38 and 10.41 ± 2.34 mm², respectively; P < 0.001), and greater LV (1.06 ± 0.31 and 1.26 ± 0.36 mm, respectively; P = 0.017). Less IC (odds ratio [OR]*100: 0.935 [95% confidence interval: 0.894, 0.979], P = 0.004) and IT₇₅₀ (OR*100: 0.904 [0.8294, 0.987], P = 0.024), greater central corneal thickness (OR*100: 2.100 [1.245, 3.542], P = 0.005), greater LV (OR: 66.7 [2.529, 1761.3], P = 0.012), less ACA (OR: 0.386 [0.193, 0.774], P = 0.007), and less ACD (OR*100: 0.912 [0.855, 0.972], P = 0.005) were significantly associated with prediction of APAC. CONCLUSIONS. Greater LV was the most prominent feature of affected eyes compared to fellow eyes in APAC patients when assessed by AS OCT. This may play a role in the development of acute attack in primary angle closure.