Reflective meniscometry: a new field of dry eye assessment

To report a newly developed noninvasive method to measure the radius of tear meniscus curvature (reflective meniscometry) and its application to normal eyes, dry eyes, and other ocular surface conditions.

Two types of meniscometer--photographic and video--were devised. Both use tear meniscus as a concave mirror, and a specular reflex of an illuminated target at the meniscus was photographed or videotaped to obtain the radius of tear meniscus curvature. The photographic system was applied to 45 normal and 32 dry eyes; in the dry eyes, the radius of tear meniscus curvature was compared to the results of other dry eye examinations. The video system was used to examine meniscus formation on the ocular surface in patients with ocular surface irregularities.

The radii of tear meniscus curvature were significantly lower in dry eyes (0.250 +/- 0.086 mm, mean +/- SD) than in normal eyes (0.365 +/- 0.153; p = 0.0003). There were significant correlations between the radius and fluorescein staining score (p = 0.0032) and the grading of interference colors on the precorneal oil film (p = 0.0125). Videomeniscometry demonstrated the tear meniscus to be very stable and proved to be useful in the study of menisci at the edge of rigid contact lenses and other menisci encountered in ocular surface disorders.

Measurement of the radius of tear meniscus curvature may be useful in the diagnosis of dry eyes. Reflective meniscometry is expected to find wide applications in the analysis of tear meniscus in ocular surface disorders.