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

© 2022 Elsevier B.V.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.