Lens Thickness-to-Anterior Chamber Depth Ratio: A Biometric Determinant of Chamber Angle Width in Han Chinese Cataract Patients.

Purpose: The purpose of this study was to individuate a novel ocular biometric index, the lens thickness-to-anterior chamber depth (LT/ACD) ratio, and identify its role in explaining anterior chamber angle width (ACAW) in Han Chinese patients with cataract. Methods: We enrolled 400 patients with cataract with phakic eyes. According to the axial length (AL), the eyes were divided into short eyes (AL < 22 mm, n = 100), medium eyes (22 ≤ AL < 24 mm, n = 100), medium‒long eyes (24 ≤ AL < 26 mm, n = 100), and long eyes (AL ≥ 26 mm, n = 100). We used a Pentacam HR to determine ACAW and an IOLMaster 700 to measure ACD and LT. A narrow chamber angle was defined as an ACAW < 20 degrees. Results: Using a multivariable linear model, which included the LT/ACD ratio, age, sex, AL, white-to-white, keratometry, central corneal thickness, and pupil diameter, the LT/ACD ratio was the strongest determinant of ACAW in the total group (standardized regression coefficient [β] = -0.71), short eyes (β = -0.71), medium eyes (β = -0.69), medium-long eyes (β = -0.72), and long eyes (β = -0.63). The LT/ACD ratio remained the strongest determinant of ACAW in eyes with an ACD < 3.0 mm (β = -0.51) or an LT ≥ 5.0 mm (β = -0.64). Multivariable logistic analysis revealed a significant association between a greater LT/ACD ratio and the presence of angle narrowness in the total group (odds ratio = 156.7, 95% confidence interval [CI] = 10.8-2270.4). An LT/ACD ratio of 1.8 could indicate angle narrowness (area under the curve = 0.94). Conclusions: In Han Chinese patients with cataract, the LT/ACD ratio can be used as an ocular biometric determinant of ACAW. An LT/ACD ratio exceeding 1.8 could effectively identify the presence of angle narrowness.