A comparative study on intraocular pressure under various anesthetics in cynomolgus monkeys (Macaca fascicularis).

Background: Nonhuman primates (NHPs) are superior model for ocular research due to its morphological and physiological similarities with humans. Thus, the effect of four different anesthetic combinations [ketamine (10 mg/kg), ketamine + xylazine (7 + 0.6 mg/kg), zoletil (4 mg/kg), and zoletil + xylazine (4 + 0.2 mg/kg)] on intraocular pressure (IOP) was determined in cynomolgus monkeys.

Results: The administration of ketamine + xylazine or zoletil + xylazine resulted in lower IOP compared to ketamine or zoletil alone. Moreover, the IOP in male monkeys was higher than in females. The difference between the right and left eye was not found.

Conclusions: Anesthetics affected the IOP, and gender differences should be considered when measuring the IOP of nonhuman primates (NHPs).