PURPOSE: We sought to investigate anatomic mechanisms of angle narrowing by assessing ocular biometric determinants of anterior chamber angle width. DESIGN: Population-based cross-sectional study. METHODS: Subjects ≥50 years of age from the Chinese American Eye Study underwent a comprehensive ocular examination, including anterior segment optical coherence tomography imaging and ultrasound A-scan. Independent variables, including anterior chamber depth (ACD), lens vault (LV), iris curvature (IC), anterior chamber width, lens thickness, vitreous cavity depth, and axial length, and dependent variables, including angle opening distance, were measured in 1 randomly selected eye per subject. Univariable and multivariable regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squares (SPCC) were used to assess relative and unique contributions by independent variables to angle width. RESULTS: Two thousand two hundred twenty-five subjects (1433 women and 834 men) were included in the analysis. All biometric parameters except lens thickness differed between men and women (age-adjusted P < .001). In model 1A (R = 0.66), which included ACD, lens thickness, and vitreous cavity depth, ACD (SRC = 0.64, SPCC = 0.19) and IC (SRC = -0.26, SPCC = 0.041) were the strongest determinants of angle opening distance. In model 1B (R = 0.58), which included LV and axial length, LV (SRC = -0.46, SPCC = 0.1) and IC (SRC = -0.3, SPCC = 0.047) were the strongest determinants of angle opening distance. Determinants of angle width were similar in separate multivariable models for men and women. CONCLUSIONS: ACD, LV, and IC are the strongest determinants of angle width in Chinese Americans. Sex-related differences in angle width are explained by differences among biometric measurements. These results provide insights into anatomic mechanisms of angle narrowing and have important implications for quantitative assessments of angle closure eyes.
University of Southern California Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, California, USA. Electronic address: firstname.lastname@example.org.Full article