Paugh JR, Tse J, Nguyen T, et al. - Researchers focused on the influences of volume and method on fluorescein tear breakup time (TBUT) values and assessed test effectiveness in an independent sample free of selection bias. By means of a battery of dry eye tests (DETs), the participants were evaluated. On separate days, they randomized participants to the DET, standard strip, and liquid NaFl. TBUTs from video recordings were measured by a masked examiner. They assessed participants for effectiveness using volumes of 5.0 and 2.0 μL mL of NaFl for TBUT. In this study, the use of the 3 clinical methods with video recordings revealed little difference in TBUT. In the analysis using liquid NaFl, the excellent diagnostic accuracy of the TBUT test was revealed as well as a cut-point of 5.3 to 6.0 seconds was identified as the optimum to distinguish normals from persons with dry eye.