Assessment of tear film optical quality in a young short tear break-up time dry eye: Case-control study

BACKGROUND: The aim of the study was to evaluate the dynamic changes of tear film optical quality in a short tear break-up time (TBUT) dry eye by using a double-pass system. METHODS: Thirty-five short TBUT dry eye participants and 43 control subjects without dry eye were included in this study. One eye for each subject was analyzed. The Objective Scatter Index (OSI), modulation transfer function (MTF), and strehl ratio (SR) were recorded within a 20-second period with the participants asked to blink freely, and 10 successive seconds of nonblinking immediately after a blink was recorded to analyze the tear film OSI. The mean tear film OSI in 10 successive seconds, ΔOSI, and ΔOSI/time were evaluated. The correlation between tear film OSI and MTF, and the correlation between tear film OSI and MIT were also analysed. RESULTS: Short TBUT dry eye participants showed significant deterioration of MTF and SR compared to control subjects. The mean tear film OSI in 10 successive seconds was significantly higher in dry eye participants than in control subjects. The mean OSI of the tear film (0–5 seconds) and the mean OSI of the tear film (6–10 seconds) were significantly higher in dry eye participants than in control participants. Moreover, the ΔOSI was significantly higher in dry eye participants than in control participants. The tear film OSI was significantly correlated with the MTF and the SR. CONCLUSIONS: The tear film OSI of short TBUT dry eye participants is significantly increased in the early stage. Tear film instability in short TBUT dry eye participants has a significant effect on optical quality.