Abstract
Purpose :
To determine the utility of strip meniscometry tube (SMTube), a commercially available test to assess tear production by comparing to measurements of tear turnover rate (TTR) by the gold standard method, fluorophotometry. This will determine if this new test can be adopted to allow the diagnosis of aqueous deficient dry eye (ADDE), and inform appropriate clinical management.
Methods :
Thirty two participants (15 dry eye patients with ADDE and 17 normal subjects) were enrolled in the study (age range 27-84). TTR of the right eye of each subject was measured with an automated scanning fluorophotometer (Fluorotron Master; Coherent Radiation, Inc, Palo Alto, CA, USA). This took 20 minutes. Strip meniscometry tube (SMTube) was then applied to the lateral lower lid tear meniscus of the same eye. At the end of 5 seconds, the length of the stained portion was measured. Tear meniscus height (TMH) was then measured using a slit lamp and eyepiece graticule.
Results :
Significant differences between the ADDE and the control group were respectively as follows (Mean ± SD) TTR 7.89±1.79, 19.57±5.90 % min-1 (P = 0.000), SMtube 3.2±1.1, 5.7±2.3 mm (P = 0.001) and TMH 0.18±0.04, 0.24±0.03 mm (P = 0.042). Moreover, significant correlations were found for all diagnostic tests TTR/SMtube (rho=0.78, P=0.000), TTR/TMH (rho=0.67, P=0.000) and SMtube/TMH (rho=0.47, P=0.007). The gold standard diagnostic test of TTR, fluorophotometry is not readily available in a clinical setting. As TTR and SMtube show a strong correlation, it can be used as a surrogate measure. Using a ROC curve, it was found that the SMtube showed a sensitivity of 88% and a specificity of 67 % at a cutoff value of 3.75 mm.
Conclusions :
The study shows that the SMtube test is a viable alternative to TTR by fluorophotometry as a measure of tear production. SMTube is an easy, quick and low-cost technique. Furthermore, it is effective as a single test for the diagnosis of ADDE.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.