Effects of Intravenous Detomidine on Intraocular Pressure Readings Obtained by Applanation Tonometry in Clinically Normal Horses

This study was conducted to determine effects of intravenous detomidine on intraocular pressure (IOP) readings obtained by applanation tonometry in clinically normal horses. Twenty horses were randomly divided into two groups of 10 each (treatment and control). All horses in the treatment group received intravenous detomidine alone (20 μg/kg). The horses in the control group received only intravenous saline (0.2 mL/100 kg). The IOP values were measured before the treatment (T0) and then at 5 (T5), 20 (T20), 60 (T60), and 120 (T120) minutes after drug administration in both groups. A significant decrease in IOP values was observed in both right and left eyes of the horses in the treatment group at T5, T20, and T60 in comparison with the baseline values (P < .001). The observed decrease was only statistically significant in the right eyes of the treatment group horses at T120 (P = .044). Mean IOP was not significantly altered at any time point during the treatment period compared with the baseline evaluations in both eyes of the horses in the control group. This study demonstrates that the use of intravenous detomidine lowers IOP quickly.