[Diagnostic value of the direct assessment of tear secretion method]

Dry eye syndrome (DES) is one of the most common conditions among patients visiting ophthalmologists. Traditional methods for assessing tear production have significant limitations as they depend on multiple factors and demonstrate low reproducibility. Therefore, there is a need for more accurate and objective assessment approaches, such as the direct assessment of tear secretion (DATS) method.

This study aimed to evaluate the diagnostic value of DATS compared to conventional tear production assessment methods.

The prospective study included 35 patients (70 observations): 34 observations in healthy volunteers, and 36 in patients with DES. The technique for DATS involved visualization of lacrimal gland ducts using fluorescein staining, video recording of secretion, and quantitative analysis of tear fluid volume using specialized software. All participants additionally underwent Schirmer's test, lacrimal meniscometry, and Ocular Surface Diseases Index (OSDI) questionnaire. Statistical analysis was performed using non-parametric tests (Mann-Whitney, Spearman) and ROC analysis with construction of AUC curves and determination of optimal diagnostic thresholds.

DATS values differed significantly between groups: 0.68 (0.41; 1.11) μl/min in healthy subjects versus 0.25 (0.04; 0.62) μl/min in dry eye patients (p=0.006). A moderate inverse correlation was found between DATS and OSDI scores (r=-0.41, p<0.001). ROC analysis demonstrated high diagnostic efficacy of DATS (AUC=0.85) with an optimal threshold of 0.3 μl/min (sensitivity 85.3%, specificity 52.8%), outperforming conventional methods.

DATS proved its diagnostic value as a method for direct assessment of lacrimal gland function and may become a promising tool in clinical practice. Further studies are needed to standardize the protocol and validate the method in larger patient cohorts with different forms of DES.