Effects of medetomidine and dexmedetomidine on intraocular pressure, pupil size, and tear secretion in clinically normal Ghezel sheep

Abstract

The objectives of the study were to investigate the effects of dexmedetomidine and medetomidine on intraocular pressure (IOP), pupil size (PS), and tear secretion (TS) in sheep. A total of sixteen female Ghezel sheep aged 24 ± 6 months (mean + standard deviation) and weighing 54.3 ± 8.9 kg (mean ± standard deviation) were randomly selected for the experimental study. Sheep were randomly divided into two groups consisting of Dex (5 μg/kg dexmedetomidine, intravenously), and group Med (10 μg/kg medetomidine, intravenously) with eight animals in each group. The IOP, PS, and TS were measured before drug administration (T0), and after the drug administration at 15-minute intervals for 45 min (T15, T30, and T45). The mean IOP, PS, and TS values at T0 between the right and left eyes showed no significant differences (P = 0.83, P = 0.23 and P = 0.45, respectively). The IOP and TS were significantly decreased in both groups compared to baseline (P < 0.05). Although PS decreased in both groups, the reduction was not statistically significant (P > 0.05). For IOP, PS, and TS at any time point, there was no significant difference between the two groups (P > 0.05). In sheep, dexmedetomidine and medetomidine administration decreased the IOP and TS, whereas no significant alterations were observed in PS.