Dry Eye Disease Lowers OCT Image Quality Through Tear Film Instability

Tear film instability in dry eye disease causes optical distortion, which is detrimental to the quality of OCT images. Be sure to ask patients to blink immediately before being scanned, and then check the SSI of the result to confirm that an adequate signal strength was used. Photo: Kesimal B, et al. BMC Ophthalmol. May 8, 2026. Click image to enlarge. Given the increasing reliance on OCT scans in eye care, doctors and techs must be mindful potential sources of image artifacts or other forms of spurious data. A recent study found that dry eye disease reduced OCT image quality, with worse tear film stability linked to lower signal strength even in eyes without media opacity.Researchers evaluated 154 right eyes from 77 patients with dry eye disease (DED) and 77 age- and sex-matched healthy controls in a cross-sectional observational study. Participants were adults aged 18 years and up. Patients in the DED group had Ocular Surface Disease Index (OSDI) scores of 13 or higher, along with at least one sign of tear dysfunction, including a Schirmer I test result of 10mm or less or a non-invasive tear breakup time (NIBUT) under 10 seconds. Patients with retinal disease, glaucoma, prior ocular surgery, cataract, high refractive error, autoimmune disease and recent contact lens wear were excluded.The DED group showed significantly worse ocular surface data and lower OCT image quality than the control patients. A metric called Signal Strength Index (SSI) “is a key parameter that reflects the quality of the OCT scan,” the researchers wrote in their paper. “SSI represents the intensity of the signal received during the OCT scan and is a direct indicator of image quality.” Higher signal intensities generally lead to clearer images with better segmentation and reduced motion artifacts, they explained.In this study, the SSI was 56.5 in the dry eye group and 63.9 in the controls, while optic nerve head SSI measured 59.4 vs. 67.9, respectively. The lower SSI values correlated with worse OSDI scores and shorter NIBUT measurements, while higher Schirmer scores and longer NIBUT values correlated with better OCT signal quality. The authors noted in the paper that “tear film instability reduces OCT signal quality in DED, even without media opacities.”They also suggested that tear film instability may create light scatter and optical irregularities that reduce OCT signal reliability and potentially affect retinal nerve fiber layer measurements. Although each scan met manufacturer-recommended SSI thresholds, dry eye patients still demonstrated lower-quality imaging, suggesting that technically acceptable scans may still contain subtle inaccuracies. The authors recommended optimizing the ocular surface before OCT imaging, particularly in patients undergoing glaucoma monitoring or longitudinal retinal evaluation. The suggested strategies included encouraging blinking before scans and using artificial tears prior to performing the imaging.Click here for the source. Kesimal B, Kocamiş S. Investigation of the impact of tear film dynamics on optical coherence tomography image quality in patients with dry eye disease. BMC Ophthalmol. May 8, 2026. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.