Ocular Biometric Determinants of Dark-to-Light Change in Angle Width: The Chinese American Eye Study.

Abstract PURPOSE To assess ocular biometric determinants of dark-to-light change in anterior chamber angle width and identify dynamic risk factors in primary angle closure disease (PACD). DESIGN Population-based cross-sectional study. METHODS Chinese American Eye Study (CHES) participants underwent anterior segment OCT (AS-OCT) imaging in the dark and light. Static dark and light biometric parameters, including angle opening distance (AOD750), anterior chamber width (ACW), lens vault (LV), and pupillary diameter (PD) were measured and dynamic dark-to-light changes were calculated. Contributions by static and dynamic parameters to dark-to-light changes in AOD750 were assessed using multivariable linear regression models with standardized regression coefficients (SRCs) and semi-partial correlation coefficients squares (SPCC2). PACD was defined as three or more quadrants of gonioscopic angle closure. RESULTS 1,011 participants were included in the analysis. All biometric parameters differed between dark and light (p-value CONCLUSIONS Beneficial angle widening effects of transitioning from dark to light are attenuated in eyes with PACD, which appears related to aberrant dark-to-light change in ACW. These findings highlight the importance of assessing the angle in both dark and light to identify potential dynamic mechanisms of angle closure.