The effects of ketamine-midazolam anesthesia on intraocular pressure in clinically normal dogs

OBJECTIVE: To determine the effects of intravenous ketamine-midazolam anesthesia on intraocular pressure (IOP) in ocular normotensive dogs. ANIMALS: Thirteen adult mixed-breed dogs. PROCEDURES: Dogs were randomly assigned to treatment (n = 7) and control (n = 6) groups. Dogs in the treatment group received intravenous ketamine 15 mg/kg and midazolam 0.2 mg/kg and dogs in the control group received intravenous saline. The time of intravenous drug injection was recorded (T(0)). Measurements of IOP were then repeated 5 min (T(5)) and 20 min (T(20)) following the intravenous administration of ketamine-midazolam combination and saline in both groups. RESULTS: Measurements showed normal IOP values in both groups. The mean + or - SD baseline IOP values for treatment and control groups were 13.00 + or - 1.47 and 10.33 + or - 2.20, respectively. For baseline IOP values, there was no significant difference between treatment and control groups (P = 0.162). In the treatment group, the subsequent post-treatment mean + or - SD values were 15.64 + or - 2.17 (5 min), and 14.92 + or - 1.98 (20 min). There was no evidence of statistical difference between baseline values and post-treatment values after treatment with ketamine-midazolam (P(5) = 0.139; P(20) = 0.442). In control eyes, the mean + or - SD values at 5 and 20 min were 10.41 + or - 2.01 and 10.16 + or - 1.69, respectively. There was no significant difference between baseline values and post-treatment values in control group (P(5) = 1.000; P(20) = 1.000). CONCLUSION: Ketamine-midazolam combination has no clinically significant effect on IOP in the dog.