Effects of Intravenous Detomidine on Schirmer Tear Test Results in Clinically Normal Horses

• Published in: Journal of equine veterinary science 2017-08, Vol.55, p.97-99
• Main Authors: Selk Ghaffari, Masoud, Brooks, Dennis E., Sabzevari, Amin, Ghamsari, Seyed Mehdi, Mansoor Lakooraj, Hamed, Shad, Hussein
• Format: Article
• Language: English
• Subjects: Detomidine; Horse; Schirmer tear test; STT; Tear production
• ISSN: 0737-0806; 1542-7412
• DOI: 10.1016/j.jevs.2016.04.099

This study was conducted to determine the effects of intravenous detomidine on Schirmer tear test (STT) results in clinically normal horses. Eighteen adult horses were randomly divided into two groups of nine horses each. The treatment group was sedated with intravenous detomidine alone (20 μg/kg), and the control group received only intravenous saline (0.2 mL/100 kg). Schirmer tear test was performed just before intravenous administration of detomidine or saline in treatment and control groups, respectively. Schirmer tear tests were repeated 5, 20, 60, and 120 minutes later. Horses enrolled in this study consisted of nine males and nine females. Breeds were Arabian and Hanoverian, ranging from 3 to 6 years in age. In the treatment group, the pretreatment and subsequent posttreatment mean ± standard deviation values were 17.0 ± 6.9 (0 minutes), 11.8 ± 2.9 (5 minutes), 12.1 ± 2.0 (20 minutes), 12.1 ± 3.1 (60 minutes), and 15.0 ± 2.8 (120 minutes) mm wetting/min. In this group of horses, a significant reduction was observed in STT values at 5, 20, and 60 minutes after treatment with detomidine hydrochloride in comparison to the pretreatment values (analysis of variance with post hoc testing; P5 = 0.004, P20 = 0.007, P60 = 0.006). There was no significant difference between baseline values and posttreatment values in the control saline group (P ≥ .08). We conclude that intravenous detomidine causes a significant reduction in STT values in clinically normal horses. In horses, practitioners should measure STT values before intravenous administration of detomidine to accurately assess the results. •We report the effects of intravenous detomidine on Schirmer tear test results in clinically normal horses.•This data will assist veterinary ophthalmologists for more accurate evaluation of Schirmer tear test results in horses sedated with intravenous detomidine.•We conclude that intravenous detomidine causes a significant reduction in Schirmer tear test values in clinically normal horses.•In horses, practitioners should measure Schirmer tear test values before intravenous administration of detomidine to accurately assess the results.