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Anat Galor, Yoel Cohen, Yoel Arieli, Shlomi Epshtin, Raanan Gefen, Alon Harris; Blink dynamics in healthy versus dry eye subjects as assessed by a novel device. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6769.
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© ARVO (1962-2015); The Authors (2016-present)
Understanding the dynamics of the natural blink cycle is an essential component to understanding tear film health and disease. The purpose of this study was to use a new device (Tear Film Imager, TFI) to evaluate the dynamics of the muco-aqueous layer throughout the entire inter-blink period and compare dynamics between healthy and lipid deficiency dry eye (DE) subjects.
The TFI (Tear Film Imager) is a new device that uses spectral analysis combined with wide field of view imaging to achieve nanometer resolution of the tear film. As it obtains more than 10 measurements per second, the TFI can capture the blink to blink dynamics of the tear film. For the study, 29 subjects with normal external ocular anatomy were recruited and underwent clinical testing and TFI imaging. Subjects were split into 2 groups based on the presence of DE signs. Controls were defined by TBUT>7sec, corneal staining=0, AND unanesthetized Schrimer>10 mm/5min in both eyes; lipid deficiency DE was defined by MGD>3 (combined score of meibum quality and number of expressible glands) AND 1 or more of the following: Schirmer≤10 mm/5min, TBUT≤7sec, or corneal staining≥1 in at least one eye.<!--![endif]---->
The TFI revealed the dynamic behavior of the muco-aqueous layer. Immediately after a blink, for few seconds, there was a rapid decay of the muco-aqueous layer thickness (MALT), followed by a quasi-stable period that manifest with a steady decrease of the layer thickness until a new blink event. Every blink reset the MALT with similar subsequent behavior thereafter. Individuals with DE had a thinner MALT (average value of measurements during the quasi-stable period), DE 2881±712nm vs. control 3602±783nm, p=0.026, that decreased at a faster rate than controls, DE -42.0±50.0nm/s vs. control -17.7±22.3nm/s.
This study reveals the dynamic nature of the MALT between blinks. Further studies are required to explore how the capability to measure interblink tear film dynamics will impact the clinical care of individuals with DE.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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