Differences of anterior segment features in fellow eyes of primary angle closure glaucoma and healthy eyes

To compare healthy eyes to the fellow eyes of acute primary angle closure (F-APAC), healthy eyes to the fellow eyes of chronic primary angle closure glaucoma (F-CPACG), and these fellow eyes to each other (F-APAC vs. F-CPACG). This study included patients with PACG (72 eyes) and healthy individuals (22 eyes). Parameters were measured on ultrasound biomicroscopy images, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber area (ACA), lens vault (LV), relative position lens vault (RPLV), anterior segment depth (ASD), angle opening distance at 500 μm (AOD₅₀₀), trabecular iris space area at 500 μm (TISA ₅₀₀), trabecular iris angle at 500 μm (TIA₅₀₀), iris thickness at 500 μm (IT₅₀₀), peripheral iris thickness maximum (PIT_MAX), iris curvature (IC). Multivariate logistic regression analysis was performed to determine the most important parameters associated with F-APAC compared with F-CPACG. In total, 94 eyes of 94 patients were included. The ACD(P < 0.001), ACW(P < 0.018), ACA(P < 0.001), ASD(P = 0.006), AOD₅₀₀(P < 0.001), TIA₅₀₀(P < 0.001) and TISA₅₀₀(P < 0.001) of the F-APAC were smaller than the healthy, and LV(P < 0.001), RPLV(P < 0.001), IC(P < 0.001) were larger than that. The ACD(P < 0.001), ACA(P < 0.001), ASD(P < 0.001), AOD₅₀₀(P < 0.001), TISA₅₀₀(P < 0.001) and TIA₅₀₀(P < 0.001) of the F-CPACG were smaller than the healthy, and the LV(P < 0.001), RPLV(P < 0.001), PIT_MAX(P = 0.030), IC(P < 0.001) were larger than that. The LV(P = 0.027), AOD₅₀₀(P = 0.013), TISA₅₀₀(P = 0.03), TIA₅₀₀(P = 0.006), IC(P = 0.48) of F-APAC were larger than F-CPACG, and PIT_MAX (P = 0.037) was smaller than F-CPACG. Multivariate logistic regression showed that only larger LV was significantly associated with APAC(P = 0.017). LV (AUC, 0.643) performed relatively in distinguishing the F-APAC and the F-CPACG. Anterior shift of the lens and iris bombe promoted the occurrence of APAC, thickening of the peripheral iris played vital roles in CPACG. Additionally, the LV was an important parameter to distinguish APAC or CPACG.