Abstract
Purpose :
Dry eye (DE) is an umbrella term that encompasses a wide range of signs. Currently available tests do not capture all aspects of tear film status thus, novel instruments are needed. We examined tear film dynamics with Tear Film Imager (TFI, AdOM, Israel), a machine that measures lipid, muco-aqueous level thicknesses and dynamics over time with nanometric resolution. We report ranges and stability of these novel metrics and their correlation with traditional DE diagnostic tests.
Methods :
Retrospective study of 34 individuals who underwent an ocular surface assessment and TFI imaging. Participants were grouped based on tear function as 1) healthy (tear break-up time, TBUT>10s, Schirmer, Sch>10mm, n=15); 2) evaporative (TBUT<10s, Sch>10mm, n=8); 3) aqueous deficient (TBUT>10s, Sch<10mm, n=6); and 4) mixed (TBUT<10s, Sch<10mm, n=5). Individuals had up to 3 scanning sessions of the right eye, two at baseline and one ~1 week later. High-quality scans were selected. Tear film metrics included: mucous-aqueous layer thickness (MALT), mucous-aqueous thinning rate (MALTR), lipid layer thickness (LLT), lipid break-up time (LBUT), lipid map uniformity (LMU) and inter-blink interval (IBI).
Results :
Mean age was 31±9.1 years, 79% self-identified as White, 59% as female, and 53% as Hispanic. A total of 65 scans were found to be of high quality. Median MALT for the first high quality scan for each participant was lowest in the mixed DE group (2518nm, 1561–4263nm) compared to the other groups (healthy: 2933nm, 1624–4817nm; evaporative 3882nm, 2404–5156nm; aqueous: 3178nm, 2023–4855nm). Median LLT was also lowest in the mixed group (37.6nm, 11.9–76.8nm vs. healthy: 53.8nm, 11.1–137.5nm; evaporative 38.3nm, 15.5–117.1nm; aqueous: 50.4nm, 35.3 – 127.2nm). Overall, heterogeneity was noted with respect to all TFI measures within and across groups. Paired t-tests comparisons of TFI scans taken on the same (n=13) and repeat visit (n=18) showed no statistically significant changes in any parameters. MALT was not significantly correlated with Schirmer (r=0.24, n=31), LLT was related to TBUT (r=0.35, p=0.05, n=33).
Conclusions :
TFI can quantify aqueous and lipid layer tear metrics that cannot be assessed with current testing. TFI measurements may offer an objective way to reclassify ocular surface diseases but further studies in this regard are needed.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.