Objective assessment of the drainage function of the lacrimal drainage system based on the dye disappearance test

The assessment of lacrimal drainage function remains a diagnostic challenge in clinical practice. Current methods, such as the dye disappearance test, are limited by subjectivity and lack of quantitative analysis. This study aimed to develop an objective method for evaluating lacrimal drainage function using digital analysis of fluorescein retention patterns.

A prospective study was conducted on 70 patients (140 observations), including cases without anatomical lacrimal drainage impairment, dacryostenosis, and complete obstruction. The tear film was stained with fluorescein, and ocular surface images were captured at 1, 3, and 5 minutes under standardized conditions. Fluorescein retention was quantified to analyze green pixel distribution in the HSB (hue, saturation, brightness) color space. Statistical analysis included receiver operating characteristic (ROC) curve assessment and logistic regression to determine diagnostic thresholds.

Fluorescein retention at 5 minutes demonstrated superior discriminative capacity compared to the 3-minute measurement. Clearance values significantly differed between normal and impaired drainage groups (P<0.001). The logistic regression model achieved 88% sensitivity and 93% specificity for detecting pathology. Threshold values of 55% (1-5 minutes) and 105% (3-5 minutes) optimally differentiated impaired from normal drainage.

The proposed digital quantification method provides an objective, reproducible assessment of lacrimal drainage function, overcoming the subjectivity of traditional tests. Its high diagnostic accuracy and clinical feasibility support its adoption for evaluating epiphora and monitoring treatment outcomes. Future studies should focus on automation and multicenter validation.