Abstract
Purpose:
Tear breakup time (TBUT) is a useful technique to diagnose dry eye disease (DED). Measuring TBUT using fluorescein strips adds supplemental normal saline (NS) to the tear film and does not represent the actual state of the tear film. We introduced a new TBUT—dry tear breakup time (DBUT)—and investigated its reliability.
Methods:
For measuring DBUT, 1 µl of 5% fluorescein solution was instilled on the end of an applicator using a micropipette. The applicator was sterilized using ethylene oxide gas after the fluorescein solution dried. The dried fluorescein was then instilled onto the lower palpebral conjunctiva without supplemental NS. Agreement between the two tests and their sensitivity and specificity were analyzed.
Results:
The average age of the patients was 32.1 ± 9.7 years (n = 124). The DBUT was lower than the TBUT, with a mean difference of -0.63 s. Both tests had a low statistically significant correlation with the Ocular Surface Disease Index. The cutoff value for the TBUT was 4.48 s, and the sensitivity and specificity were 0.790 and 0.548, respectively. The area under the receiver operative characteristic (AUROC) curve was 0.609 (95% confidence interval (CI): 0.517-0.695). With a cutoff value of 3.5 s for the DBUT, the sensitivity and specificity were 0.726 and 0.694, respectively. The AUROC curve was 0.724 (95% CI: 0.637-0.801).
Conclusions:
DBUT had a higher correlation with symptoms and a higher AUROC than conventional TBUT when DED was diagnosed with corneal staining. DBUT could be a useful and effective method in diagnosing DED.