Tear film osmolarity and tear fluorescein clearance tests in healthy subjects; intra- and inter-day variation study

Poster Details

First Author: N.Garc SPAIN

Co Author(s):    M. Tes   A. Enriquez de Salamanca   L. Mena   M. Calonge   M. Gonzalez  

Abstract Details

Purpose:

There are many clinical tests for the diagnosis of dry eye disease however there is no single gold standard test. Most of the tests show poor reproducibility and poor correlation with signs and symptoms; however tear osmolarity test and tear fluorescein clearance test have been considered more accurate objective diagnostic tests. The aim of this study was to evaluate repeatability and to analyse influence of circadian rhythms in the results of both tests in healthy subjects.

Setting:

IOBA, University of Valladolid, Spain

Methods:

2 microliters of tears were collected non-traumatically with a capillary tube from one eye (randomly selected) to measure tear osmolarity, also tear fluorescein clearance test was performed in 24 healthy subjects (7men, 17women; mean age 21.41, range 18-30 years).Osmolarity was analysed with a freezing-point depression osmometer: Fiske 210 and tear fluorescein clearance with Spectramax M5 fluorofotometer. Tear samples were collected at two different times of the day: between 11:00 and 13:00h and between 17:00 and 19:00h, and on three non-consecutive days, with a total of 6visits. Ocular surface disease was ruled out by the following tests: OSDI questionnaire, slit-lamp examination, Schirmer test, Phenol read thread test, tear break-up time (T-BUT) and fluorescein corneal staining. Random-Effects ANOVA model was used to evaluate intra- and inter-day effect on both tests.

Results:

Osmolarity did not show significant differences in inter or intra-day analysis however, the tear fluorescein clearance test showed a significant variation along the day (p=0.0004).

Conclusions:

Time of the day when tear fluorescein clearance test is performed must be taken into account when used to evaluate the progression of dry eye disease or effectiveness of a therapy. No evidences were found with tear osmolarity to be affected by circadian rhythms. FINANCIAL DISCLOSURE?: No