Intra-Rater Variability and Inter-Rater Reliability in Measuring Tear Osmolarity in Dogs Using the ScoutPro System.

Abstract

OBJECTIVE: To evaluate the applicability of the ScoutPro (Trukera Medical, Southlake, Texas, USA) osmolarity system for tear film osmolarity measurement in healthy dogs. ANIMALS STUDIED: Seventeen dogs (34 eyes) of dolichocephalic and mesocephalic breeds were tested. PROCEDURES: Tear osmolarity was tested with the ScoutPro osmolarity system. Two examiners performed three subsequent measurements of each eye. Intra-rater variability and inter-rater reliability were calculated. RESULTS: The technique was straightforward; instrument handling was simple. Mean tear osmolarity measured by examiner one was 323.51 ± 9.89 mOsm/L and by examiner two 326.74 ± 9.02 mOsm/L. Mean difference between examiners was 3.2 ± 11.2 mOsm/L. Paired two-tailed t-test was p = 0.1. The intra-rater variability was acceptable with a Cronbach's Alpha of 0.75 for rater one and 0.80 for rater two. There were no significant differences in the three measurements of the individual examiners. There were no significant differences in the three measurements of the individual examiners (asymptotic significance rater one was 0.56, asymptotic significance rater two was 0.11). CONCLUSIONS: Measurements with the ScoutPro osmolarity system in dogs are easy to perform. Variability and inter-rater reliability seem to be acceptable in the small group of dogs tested. Further studies regarding the reliability of the test results and the evaluation of the tear osmolarity in ocular surface disease are warranted.