Investigation of the impact of tear film dynamics on optical coherence tomography image quality in patients with dry eye disease

PURPOSE: To investigate the effect of tear film parameters on optical coherence tomography (OCT) signal strength index (SSI) in dry eye disease (DED) patients. METHODS: This cross-sectional study included 77 DED patients and 77 healthy controls. All participants underwent ocular surface index (OSDI) assessment, Schirmer I test, non-invasive break up time (NIBUT) measurement, and OCT imaging. SSI values from raster and optic nerve head (ONH) scans were recorded using the RTVue-100 device. Correlation and multivariate analyses were performed. RESULTS: DED patients exhibited significantly lower raster and ONH SSI values compared to controls (p < 0.001). SSI positively correlated with NIBUT and Schirmer, and negatively with OSDI scores (p < 0.001). NIBUT and OSDI were independent predictors of SSI in regression models. CONCLUSION: Tear film instability reduces OCT signal quality in DED, even without media opacities. Ocular surface optimization should be considered before OCT imaging to ensure accurate evaluation of measurements.