Quantitative analysis of anterior and posterior chamber parameters of primary angle-closure glaucoma based on Level set method

PURPOSE: The study aimed to accurately measure anterior and posterior chamber parameters in ultrasound biomicroscopy (UBM) images and to quantify their relationship with intraocular pressure (IOP), axial length (AL) and lens thickness (LT), enhancing the understanding of primary angle-closure disease. METHODS: UBM images of 135 patients with primary angle-closure glaucoma(PACG) and 30 healthy individuals were analyzed. The Level set method was used to measure anterior chamber depth (ACD) and posterior chamber area (PCA). Relative error and intraclass correlation coefficient (ICC) were used to assess the accuracy and consistency of these measurements compared to the ground truth. IOP, AL and LT were also measured, and the relationships between ACD, PCA, IOP, AL and LT were explored using Spearman correlation analysis. RESULTS: The Level set method yielded highly accurate measurements of ACD and PCA with low Relative errors and high ICC values. Spearman correlation analysis revealed that PCA was significantly positively correlated with both AL (R = 0.398, p = 0.002) and LT (R = 0.255, p = 0.006). In contrast, no statistically or clinically significant associations were found for the remaining parameter pairs (e.g., ACD-IOP, PCA-IOP), all of which showed |R|<0.2 and P > 0.05. CONCLUSION: The Level set method proves to be a highly accurate and consistent technique for UBM image analysis, boosting measurement efficiency and reproducibility. The significant correlations of PCA with AL and LT offer new insights into the anatomical complexity of angle-closure disease, emphasizing the posterior chamber as a critical dimension for further exploration.