Optimising the methodology for assessing tear meniscus height using digital imaging.

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Imaging

Background:

• The tear meniscus height (TMH) is a key indicator of ocular surface health and tear film stability.
• Accurate and reproducible TMH measurement is essential for diagnosing and monitoring dry eye disease.
• Digital imaging techniques offer potential for objective TMH assessment, but optimal methods require definition.

Purpose of the Study:

• To establish the optimal digital imaging method for assessing tear meniscus height.
• To compare infrared and visible light imaging for TMH measurement.
• To determine the ideal timing and location for TMH capture post-blink.

Main Methods:

• Video recording of the tear meniscus in 38 participants using the Oculus Keratograph 5M with infrared and white light.
• Extraction of still images at 0.5-second intervals post-blink for TMH measurement using ImageJ.
• Assessment of dryness symptoms (OSDI) and tear film stability (NIBUT) for correlation.

Main Results:

• A statistically significant difference in TMH was observed between infrared and white light measurements (p < 0.001).
• TMH measurements showed significant increases with repeated assessments and varied based on measurement location relative to the pupil midline (p < 0.001).
• TMH was stable between 1.0 and 2.5 seconds post-blink, with non-clinically significant differences peripherally.

Conclusions:

• Consistent TMH measurement is achievable with either infrared or white light digital imaging.
• A single image captured 1.0 to 2.5 seconds after two blinks, within 1mm of the pupil midline, is sufficient for reliable TMH assessment.
• Standardized digital imaging protocols are recommended for accurate TMH evaluation in clinical practice.