Novel Software Application Objectively Measures Tear Film Break Up Time

Dry Eye
Current diagnostic devices and traditional fluorescein measurements have often produced inconsistencies in agreement with respect to BUT measurement.

A software application may be able to objectively measure tear film breakup time (BUT), according to a study published in Optometry and Vision Science.

Researchers conducted a retrospective study of 264 participants (mean age 46.9±13.2 years, Ocular Surface Disease Index (OSDI) score, 27.3±16.28) to address the need for repeatability and reproducibility for clinically evaluating tear film stability in patients with dry eye disease (DED). They instilled 2 µL of 2% sodium fluorescein on the ocular surface and instructed all participants to blink 3 or 4 times to spread the film. Investigators performed a slit lamp evaluation and video recorded the fluorescent tear film. A total of 2 experienced observers subjectively evaluated BUT, while a third objectively measured BUT through an automatic software application. 

The 2 researchers conducting the subjective analysis pressed a button at 3 different times during each video; the final blink after spreading the tear film, the start of tear film break up, and the first blink following break up. They defined BUT as the time between the start of the measurement and the appearance of the first tear film break in the video. 

The automatic software application evaluated BUT based on video color and texture assessments in 3 steps: (1) automatic localization of sequences of interest in the video, (2) extraction of the region of interest within each frame, and (3) automatic breakup time measurement. All investigators were blind to the measurements of the other observers.

The researchers noted a significant correlation among the examiners (Intraclass correlation coefficient, 0.752; P <.001) and significant differences between the evaluations of observers 1 and 2 (P <.001). However, they did not observe a significant difference between objective measurements and those provided by either observer (P ≥.26 for both). They maintained similar results after reanalyzing data and including only mean BUT values of 15 seconds or less.

Investigators highlight the need for more objective measurements of BUT, “Breakup time interpretation has not yet been clearly defined, and it relies on the clinician’s judgment to decide when a dark spot constitutes a real breakup or only a thin area.” They state that these software applications allow for “greater objectivity in the clinical results and dry eye disease diagnosis.”

Study limitations include a potential lack of repeatability due to investigators conducting each measurement only 1 time.


Pena-Verdeal H, Ramos L, Garcia-Queiruga J, García-Resúa C, Giráldez MJ, Yebra-Pimentel E. Validation of a new software application for tear breakup measurement. Optom Vis Sci. 2022;99(2):159-166. doi:10.1097/OPX.0000000000001852