Randomized comparison of in vivo performance of TearLab® and I-PEN® osmometry in normal dogs

Abstract

Objective: To compare tear film (TF) osmolarity measured using TearLab® and I-PEN® osmometers in the same dogs without any ocular surface disease. Animal Studied: Fifty-two dogs (98 eyes) of different breeds were evaluated. Procedures: Tear film (TF) osmolarity was evaluated at 2-min intervals. The test was randomly determined, and single measurements were performed using each osmometer. Subsequently, complete ophthalmologic examinations were performed based on Schirmer tear test-1 (STT-1) analysis, tear film breakup time (TFBUT), and slit-lamp biomicroscopy. For each osmometer, the mean ± standard deviation of the TF osmolarity was calculated, and a paired Student's t-test was used to compare the values obtained. Pearson correlation analysis was performed to assess the association between osmolarity and other values such as STT-1, TFBUT, and age. Results: Tear film osmolarity determined using TearLab® (340.42 ± 15.87 mOsm/L) and I-PEN® (321.58 ± 17.39 mOsm/L) were significantly different (p