Abstract
Purpose :
To assess ocular biometric determinants of anterior chamber angle (ACA) width in a Chinese American population.
Methods :
Subjects aged 50 years or older from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA, underwent comprehensive ocular exams, including anterior segment OCT (AS-OCT) imaging and ultrasound A-scan. Biometric parameters were measured in one eye selected at random per subject. Independent parameters included anterior chamber depth (ACD), lens vault (LV), lens thickness (LT), vitreous cavity depth (VCD), axial length (AL), iris area (IA), iris curvature (IC), and anterior chamber width (ACW). Dependent parameters included angle opening distance (AOD) and trabecular iris space area (TISA) 750 um anterior to the scleral spur. Simple and multiple regression models with standardized regression coefficients (SRCs) and semi-partial correlation coefficients squared (SPCC2) identified key determinants of angle width.
Results :
Among 2,225 eligible subjects, 1433 (64.4%) were women and 834 (35.6%) were men. All biometric parameters except LT differed significantly between men and women after adjusting for age and sex (adjusted p-value<0.001). On simple regression analysis, ACD and LV were the strongest determinants of angle width (R2=0.56 and 0.49, respectively, for AOD750; R2=0.41 and 0.34, respectively, for TISA750). ACD and LV were separated on multivariate analysis due to strong collinearity (r=-0.826). In model 1A (R2 = 0.66), which included ACD and other constituents of AL (LT, VCD), ACD (SRC=0.64, SPCC2=0.19), and IC (SRC=-0.26, SPCC2=0.041) were the strongest determinants of AOD750. In model 1B (R2=0.58), which included LV and AL, LV (SRC=-0.46, SPCC2=0.1) and IC (SRC=-0.3, SPCC2 = 0.047) were the strongest determinants of AOD750. Multivariate models were less predictive of TISA750 than AOD750 (R2=0.46 in model with ACD, R2 = 0.39 in model with LV). Determinants of angle width were similar in separate multivariate models for men and women.
Conclusions :
ACD followed by LV and IC are the strongest determinants of angle width in Chinese Americans. Sex-related differences in angle width are related to differences in biometric measurements rather than their relative contributions. These results provide insight into anatomical mechanisms of angle closure and have important implications for personalized care of angle closure disease.
This is a 2020 ARVO Annual Meeting abstract.