Abstract
Purpose:
Primary angle-closure glaucoma is a significant cause of blindness in Asia. Assessment of angle configuration is important for the prevention and treatment of primary angle closure. The purpose of this study is to investigate the associations between anterior chamber angle width and other anterior segment biometric parameters, and to identify the major predictors of anterior chamber angle width in eyes with angle closure and open angle.
Methods:
We used anterior segment optical coherence tomography (AS-OCT) to examine 118 eyes of 118 angle closure patients (27 men and 91 women with a mean age of 71.1 ± 8.3 years) and 34 eyes of 34 primary open angle glaucoma patients (17 men and 17 women with a mean age of 67.7 ± 7.7 years) under dark and light conditions. After measuring the angle opening distance 500 (AOD500), anterior chamber depth (ACD), iris thickness (IT), iris convexity (IC), pupil diameter (PD), anterior chamber width (ACW), and crystalline lens rise (CLR), we performed univariate analyses and multivariate regression analyses for the AOD500 for each group.
Results:
Results: In angle closure group, the explanatory variables relevant to the AOD500 were ACD, IT, IC, PD, and ACW under both dark and light conditions (In the dark: standard coefficients (β) 0.518, −0.399, −0.281, −0.261, and −0.223, respectively, p < 0.01 for all, adjusted R2 = 0.473 In the light: β 0.413, −0.166, −0.401, −0.333, and −0.210, respectively, p < 0.01 for all except IT (p < 0.05), adjusted R2 = 0.413). In open angles group, the explanatory variables relevant to the AOD500 were ACD, IT, IC, and ACW under the dark conditions, and ACD, IT, IC, and PD under the light conditions (In the dark: β 0.578, −0.558, −0.480, and −0.262, respectively, p < 0.01 for all, adjusted R2 = 0.851 In the light: β 0.397, −0.317, −0.588, and −0.235, respectively, p < 0.01 for all, adjusted R2 = 0.828).
Conclusions:
This study quantitatively confirmed that ACD was one of the major predictors of the anterior chamber angle width under both dark and light conditions and especially under the dark conditions, IT was stronger factor rather than IC whether eyes with angle closure or open angle. Therefore this study showed that the same anterior segment anatomical or physiological principles exist between eyes with angle closure and eyes with open angle.