Tear breakup dynamics: a technique for quantifying tear film instability.

Area of Science:

• Ophthalmology
• Corneal Science
• Dry Eye Disease Research

Background:

• Dry eye disease (DED) is a prevalent condition characterized by tear film instability.
• Understanding tear film breakup dynamics (TBUD) is crucial for diagnosing and managing DED.
• Current methods for assessing TBUD may lack quantitative precision.

Purpose of the Study:

• To develop and validate a novel, quantitative measurement of tear film breakup dynamics (TBUD).
• To investigate TBUD in dry eye patients compared to control subjects.
• To correlate TBUD measurements with dry eye symptoms.

Main Methods:

• A staring contest-like protocol (S-TBUD) was employed, videotaping tear film breakup after sodium fluorescein instillation.
• Quantitative measurements included maximum blink interval (MBI), tear breakup time (TBUT), and area of tear breakup (AB).
• Dry eye (n=10) and control (n=10) subjects completed questionnaires, including the Dry Eye Questionnaire (DEQ).

Main Results:

• Dry eye subjects exhibited a significantly larger area of tear breakup (AB) (p = 0.023) compared to controls.
• While dry eye subjects had shorter TBUT and MBI, only AB reached statistical significance.
• The AB measurement showed high inter-eye correlation and correlated with some DEQ symptom measures.

Conclusions:

• The developed S-TBUD method allows objective quantification and tracking of tear breakup.
• Results suggest tear breakup stresses the cornea, potentially stimulating nociceptors.
• Dry eye subjects have less stable tear films, evidenced by a larger AB, possibly reflecting adaptation to chronic instability.