Determination of the Non-Invasive Tear Break-Up Time Cut-Off Point for Diagnosis of Dry Eye Disease and Its Correlation with Other Dry Eye Tests

Abstract

Objectives To determine optimal cut-off values for first and average non-invasive tear break-up time (NIBUT-f and NIBUT-av, respectively) in dry eye disease (DED), as well as evaluate their correlation with other tests. Materials and Methods This retrospective study included 46 patients with DED and 35 healthy controls. All subjects were assessed using the Ocular Surface Disease Index questionnaire. NIBUT measurements and meibography images were obtained using the Sirius topography device. The conventional diagnostic tests Schirmer-I, tear break-up time (TBUT), ocular surface staining (OSS), Marx line score, and lid wiper epitheliopathy (LWE) grade were performed. Results The cut-off values of NIBUT-f and NIBUT-av for DED diagnosis were identified as 10.7 and 12.2 seconds, respectively. The area under the curve (AUC) was 0.93 (95% confidence interval [CI]: 0.889-0.992) for NIBUT-f and 0.92 (95% CI: 0.872-0.985) for NIBUT-av. For the differentiation between evaporative and mixed DED subtypes, the NIBUT-av cut-off value was 7.2 seconds, with an AUC of 0.63 (95% CI: 0.512-0.743). NIBUT-av showed a positive correlation with TBUT (p<0.001, r=0.905) and Schirmer-I (p<0.001, r=0.403) but a negative correlation with OSS (p<0.001, r=-0.700), meibomian gland loss (p<0.001, r=-0.601), LWE grade (p<0.001, r=-0.597), and Marx line score (p<0.001, r=-0.539). Conclusion NIBUT is a highly sensitive and specific non-invasive diagnostic tool for DED that correlates with other ocular surface and meibomian gland function tests.