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.