Background and Aim: Post-operative loss of vision is not a common but dramatic complication. This is most often reported after spinal and cardiac surgeries. Ischemic optic neuropathy is the primary cause, but its etiology remains unclear. Retinal blood perfusion depends on mean arterial pressure and intraocular pressure (IOP). In spinal surgery, both of these can be altered by the type of prone-position surgery. Because different anesthetic agents can be used for anesthesia in spine surgery, we conducted this randomized clinical trial to compare the effects of propofol and isoflurane as maintenance anesthesia on IOP during spinal surgery in the prone position.

Methods and Materials/Patients: IOP was measured with the Tonopen Richert device in five steps before and after induction of anesthesia and during surgery every 30 minutes. A total of 72 patients were enrolled in this study.

Results: IOP decreased after induction of anesthesia with propofol, but significantly increased in patients receiving isoflurane as maintenance of anesthesia in a prone position compared with the propofol group. Systolic and diastolic blood pressure and duration of surgery in a prone position were also associated with increased IOP.

Conclusion: The present study showed that the group under anesthesia with propofol had significantly lower IOP than the group anesthetized with isoflurane.