To evaluate the diagnostic value of tear film osmolarity for non-Sjogren dry eye syndrome through measuring the correlation between tear osmolarity and several conventional dry eye parameters.

In this observational cross-sectional study, 274 patients (274 eyes) with non-Sjogren dry eye syndrome were examined using tear film osmolarity and the following conventional dry eye parameters: Schirmer's test, tear film break-up time, ocular surface disease index (OSDI), and corneal staining score. The correlations between tear film osmolarity and each conventional dry eye parameter were assessed using Spearman's correlation coefficients.

The mean tear film osmolarity of the study population was 296.34 ± 21.08 mOsm/L. The tear film osmolarity was significantly negatively correlated with the Schirmer's test value (r = -0.431, p < 0.001) and tear break-up time (r = -0.131, p = 0.031), while it was significantly positively correlated with the OSDI scores (r = 0.191, p = 0.001) and corneal staining scores (r = 0.150, p = 0.013).

Tear film instability was significantly correlated with other conventional dry eye parameters. However, additional studies are required to determine its feasibility as a stand-alone diagnostic tool.