Eye Pressure During Surgery: A Randomized Trial Compared Spinal and General Anesthesia

Eye pressure, or intraocular pressure (IOP), can change while you are under anesthesia, even when the operation is not on the eye. A randomized trial published in September 2026 in Saudi Medical Journal compared spinal anesthesia with general anesthesia in adults having lumbar spine or lower-extremity orthopedic surgery.

What the researchers did

Sixty adults were randomly assigned to spinal anesthesia or general anesthesia. IOP, mean systemic arterial pressure, and heart rhythm were recorded at set times: baseline, before the spinal injection or induction, after the injection or induction, 5 minutes after the spinal procedure or intubation, 30 minutes into surgery, at the end of surgery, and 5 minutes after surgery or extubation.

What they found

• Baseline eye pressure was similar in both groups (about 14.3 mmHg with spinal anesthesia and 14.6 mmHg with general anesthesia).
• The largest drop in IOP in both groups was right after the spinal injection or induction of general anesthesia. The drop at that point was more marked in the general anesthesia group.
• After intubation, IOP was significantly higher with general anesthesia (19.82 mmHg) than with spinal anesthesia (12.86 mmHg).
• At 30 minutes and at the end of surgery, IOP stayed lower in the spinal group than in the general anesthesia group.
• Five minutes after surgery, IOP in both groups was slightly above baseline, but the difference from baseline was not statistically significant.
• In the prone (face-down) position, IOP at mid-surgery and at the end of surgery was significantly higher than at the start in both groups, and the increase was larger with general anesthesia.

The authors concluded that IOP may rise during both types of anesthesia, but the increase was greater with general anesthesia. This was not an eye-surgery trial, and it does not tell us which anesthetic is “safer” for every patient. If you have glaucoma or already-high eye pressure and are planning surgery, it is reasonable to mention that to your surgical and anesthesia team so they can take it into account.

Source: Comparison of the Effects of Spinal Versus General Anesthesia on the Perioperative Intraocular Pressure (Saudi Medical Journal (PubMed), September 2026). This article is an educational summary written by Khanna Vision Institute and is not a substitute for medical advice.