Purchase this article with an account.
Nicole Fuerst, Mina Massaro-Giordano, Bridgette McCabe, Ilaria Macchi, Maxwell Pistilli, Gui-Shuang Ying, Vatinee Bunya; Variability of tear osmolarity in dry eye patients and controls. Invest. Ophthalmol. Vis. Sci. 2013;54(15):959.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To examine the reproducibility and quantify the variability of tear osmolarity in different populations of dry eye patients and controls.
Seventy-four eyes of thirty-seven subjects (18 Sjogren's syndrome, 10 blepharitis, and 9 controls) were evaluated for the variability of measurements using the TearLab system. Controls were defined as those with no history of symptoms or signs of dry eye disease. 94% of Sjogren’s syndrome patients and 80% of blepharitis patients were on systemic or topical dry eye medications at the time of enrollment. For all subjects, three consecutive osmolarity measurements were taken at one minute intervals in each eye to assess the within-session variability. For fifteen subjects, three measurements were taken at each of 3 time points throughout the day (9-10am, 12-1pm, 3-4pm) to examine the inter-session variability over the course of the day. The within-session and inter-session variability were assessed based on the standard error of measurement (SEM), calculated from the analysis of variance.
Among all subjects, the within session variation for a single osmolarity measurement was 14.4 mOsm/l (13.8 for SS, 8.8 for blepharitis, and 16.2 for controls). When the average of the three consecutive measurements in a single session were used, the variability of osmolarity measurement was 8.3 mOsm/l. Between-session variability was 17.2 mOsm/l for a single osmolarity measure, and 10.4 mOsm/l for an averaged measurement. The variability of osmolarity measurements between two eyes of the same subject was not correlated (pearson rho=-0.05, p=0.76).
A single measurement of tear osmolarity with the TearLab system had a standard error measurement of 14.4 mOsm/L. We did not find any correlation between eyes as far as variability of measurements. Further larger studies would be helpful in studying the utility of tear osmolarity measurements in different dry eye populations.
This PDF is available to Subscribers Only