Abstract
Purpose :
To study the association between precorneal tear-aqueous thinning rate (TTR) and non-invasive tear breakup time (NITBUT) in symptomatic soft contact lens wearers.
Methods :
The Contact Lens Dry Eye Questionnaire (CLDEQ-8), the Berkeley Dry Eye Flow Chart (DEFC), and Visual Analog Scales (VAS) for discomfort and dryness were administered to evaluate dry eye symptoms in soft contact lens wearers. Subjects with DEFC ≥3 were included in the study. Tear film videos of 5 consecutive interblink periods were taken on the right eyes using a Zeiss Meditec AG SL-120 slit lamp with Sony 3CCD Exwave HAD camera attachment. The TTR was estimated by quantifying the fluorescence intensity as a function of time over video frames and taking the percentage of thinner film (darker) area relative to visible cornea area. TTR was modeled as a function of subject characteristics, clinical measurements including NITBUT, intraocular pressure (IOP), tear osmolarity, tear meniscus height, and Schirmer strip wetted length, and subjective symptoms using multivariable linear regression. NITBUT was measured with the Medmont E300 Corneal Topographer.
Results :
Thirty-four subjects (28 female, 6 male) ages 19-43 years, completed the study. Mean (SD) dry eye symptom score for CLDEQ-8 was 16.74 (5.57), for VAS discomfort was 30.53 (17.78), and for VAS dryness was 42.82 (21.52). No significant associations were found between TTR and any measure of subjective symptoms. Shorter NITBUT was significantly associated with faster TTR (p=0.033; Figure 1), adjusting for faster TTR among females (p=0.050) and with lower IOP (p=0.024). Among females, the estimated TTR associated with the shortest observed NITBUT (2.3s) was 3.7%/s, and with the longest NITBUT (30.0s) was 2.8%/s. Among males, the estimated TTR values were 2.0%/s and 1.1%/s for the shortest and longest observed NITBUT, respectively.
Conclusions :
To our knowledge, this is the first study to evaluate the associations between a quantitative, video-based estimate of the TTR, dry eye symptoms and NITBUT. Faster TTR is associated with shorter NITBUT, and with female sex and lower IOP.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.