TEAR MENISCUS MEASUREMENT IN THE DIAGNOSIS OF DRY EYE

Purpose. Assessment of the tear film meniscus is a quantitative, minim ally invasive, direct measurement of tear film quantity. The aim of th is study was to assess the efficacy of tear meniscus parameter measure ment in the diagnosis of dry eye. Methods. Tear meniscus radius of cur vature, height, width and cross-sectional area (TMC, TMH, TMW, XSA) we re determined by photographing an optic section of the inferior tear m eniscus (colored with a min volume of fluorescein) at 120 x magnificat ion, and then scanning developed images into a computer analysis progr am. Fifteen dry eye subjects and 15 age-matched controls were assessed . Dry eye subjects satisfied the criteria of a rose bengal staining sc ore greater than or equal to 1, and a mean phenol red thread 15 s wett ed length less than or equal to 10 mm. Results. TMC, TMH and XSA were all reduced in magnitude in the dry eye group compared to the control group (mean +/- SD; TMC: 0.314 +/- 0.160 mm vs. 0.545 +/- 0.259 mm, TM H: 0.244 +/- 0.089 mm vs. 0.461 +/- 0.173 mm, XSA: 0.0082 +/- 0.0048 m m(2) vs. 0.0176 +/- 0.0103 mm(2), ANOVA, p < 0.05). Both TMC and TMH s howed good diagnostic accuracy (166.7% and 160% respectively), with a dry eye referent value of less than or equal to 0.35 mm for each param eter. TMC and TMH also showed strong correlations with the cotton thre ad test, non-invasive breakup time, and ocular surface staining scores (p < 0.01). TMH was the most powerful predictor of tear film insuffic iency. Conclusions. This study has shown tear meniscus assessment to b e a useful alternative to existing tests for dry eye.