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Tear break-up time: clinical procedures and their effects
1Department of Optometry & Radiography, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Summary
Measuring tear break-up time (TBUT) requires specifying the value used, as successive measurements show significant differences. Repeat measurements and altered eyelid opening do not consistently alter TBUT results.
Area of Science:
- Ophthalmology
- Ocular Surface Disease
- Tear Film Dynamics
Background:
- Tear break-up time (TBUT) is a critical indicator of ocular surface health.
- Standardized measurement protocols for TBUT are essential for reliable clinical assessment.
Purpose of the Study:
- To evaluate the reproducibility of sequential fluorescein-instillation TBUT measurements.
- To investigate the impact of repeat measurements and altered palpebral aperture on TBUT.
- To determine the most representative TBUT value for clinical use.
Main Methods:
- Sequential TBUT measurements using fluorescein instillation in young Hong Kong Chinese subjects.
- Repeat TBUT measurements after a six-minute interval (TBUTR).
- TBUT measurements with subjects widening their eyes to increase palpebral aperture (TBUTW).
Main Results:
- Median TBUT values increased significantly from the first to the third successive measurement.
- No significant difference was found between repeat TBUT measurements taken on different days (TBUTR) or when excluding outlier data for widened eyes (TBUTW).
- No significant correlation between palpebral aperture size and TBUT values.
Conclusions:
- It is crucial to specify which sequential TBUT measurement is reported.
- Repeat measurements and voluntary widening of the eyes do not consistently alter TBUT values.
- Standardization of TBUT measurement protocols is recommended for clinical consistency.