Tear Break Up Time

Assessing Tear Film Stability

Tear Break-Up Time (TBUT) is a crucial diagnostic test used in optometry to assess the stability of the tear film, an important factor in eye health and comfort. This test measures the interval between a complete blink and the appearance of the first dry spot on the corneal surface after instillation of a fluorescein dye. A short TBUT, typically less than 10 seconds, indicates rapid tear evaporation and is a key diagnostic criterion for dry eye syndrome. By evaluating TBUT, optometrists can gain insights into the protective quality of the tear film, which is essential for maintaining corneal health and preventing ocular surface disease. Accurate measurement of TBUT helps in diagnosing tear film disorders and formulating effective management strategies, including recommending lubricating eye drops, environmental modifications, or more advanced therapies depending on the severity of the condition.

Expected TBUT Values

ResultBreak Up Time
Normal≥10 seconds
Abnormal<10 seconds