Clinical Significance of Tear Film Osmolarity for Non-Sjögren Dry Eye Diagnosis

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Corneal Microstructural Changes in Non-Sjogren Dry Eye Using Confocal Microscopy: Clinical Correlation

PURPOSE: To investigate the relationship between changes of corneal epithelium and subbasal nerves in non-Sjogren dry eye using in vivo confocal microscope (IVCM) and self-reported clinical symptoms. METHODS: The present study included 40 patients with dry eye and 18 healthy control subjects. The dry eye group underwent an evaluation of dry eye symptoms using visual analogue scale (VAS) score and was subdivided into 2 groups; score 0-5 as the low VAS score (LVS) group and score 6 - 10 as the high VAS score (HVS) group. The tear film break-up time, fluorescein staining, Schirmer test and microstructural imaging of epithelium, and subbasal nerve at cornea center with IVCM were performed on both eyes of each patient. Twenty-three normal eyes and 54 eyes of dry eye patients were included in the study. Cell densities and morphological characteristics were analyzed using ImageJ and NeuronJ softwares. RESULTS: Both LVS and HVS groups had decreased cell density of superficial, intermediate, and basal epithelium (p < 0.001). Intermediate epithelial cells were more decreased in the dry eye group with more severe symptoms (p < 0.0001). Subbasal nerve density (p < 0.005) was more decreased and nerve beadings, tortuosity, and reflectivity increased in the HVS group than both LVS and control groups (p < 0.05). CONCLUSIONS: The alterations of corneal cellular level in dry eye patients visualized using IVCM are correlated with pathology and clinical symptoms and may be useful objective criteria in diagnosis and monitoring treatment efficacy.