Investigating the effect of tear film dynamics on OCT scan quality

Researchers from Diskapi Yildirim Beyazit Education and Research Hospital in Ankara, Turkey have explored the effect of tear film dynamics on the quality of optical coherence tomography (OCT) scans.

Writing in BMC Ophthalmology, the scientists described how they conducted a series of tests on a group of 77 patients with dry eye disease and 77 healthy patients without the condition.

All study participants underwent an ocular surface index assessment, Schirmer I test, non-invasive break up time measurement and OCT imaging.

The researchers found that signal strength index (SSI) – a key indicator reflecting the quality of an OCT scan – was reduced among the patients with dry eye disease.

“This study provides compelling evidence that ocular surface instability, specifically tear film disruption in dry eye disease, significantly impairs the SSI of spectral-domain OCT scans,” the authors noted.

“Notably, this reduction in signal quality occurs even in eyes free of media opacities or significant refractive error, underscoring the tear film as a critical, yet underappreciated, determinant of OCT image reliability,” they shared.

The researchers suggested that in light of this finding, clinicians should take steps to mitigate the effect of ocular surface instability on OCT signal.

These include encouraging patients to blink immediately before the OCT image is taken, avoiding performing OCT scans after prolonged visual tasks (such as perimetry) and using artificial tears before OCT scans are taken in patients with known or suspected dry eye disease.