Comparison of the Effects of Spinal Versus General Anesthesia on the Perioperative Intraocular Pressure: <i>A prospective, randomized clinical trial</i>

Objectives: To evaluate the effects of spinal and general anesthesia on the intraocular pressure (IOP) in patients, who had lumbar spine and lower extremity orthopedic surgeries Methods: Sixty adult were randomly classified into Group spinal anesthesia (SA) and Group general anesthesia (GA). The IOP, mean systemic arterial pressure, and heart rhythm were measured at 6 pre-determined timepoints (T0: Baseline, T1: Before spinal procedure or anesthesia induction, T2: After injection with intrathecal or anesthesia induction, T3: 5th minutes (min) after spinal procedure or tracheal intubation, T4: 30th min intraoperative, T5: At the end of surgery, T6: 5th min after surgery or tracheal extubation in the operation room Results: The baseline IOP and IOP1 measurements during were not significantly different between the groups (SA = 14.28 ± 0.8 mmHg; GA = 14.62 ± 0.9 mmHg, p = 0.923; and IOP1: SA = 15.83 ± 0.9 mmHg; GA = 15.88 ± 0.9 mmHg, p = 0.929). The most significant decrease in IOP in both groups was recorded at T2 (SA: 12.37 ± 0.6. GA: 12.24 ± 0.4, p < 0.001). The decrease in IOP2 was more significant in the GA group. The IOP3 was significantly higher in GA group after intubation (GA: 19.82 ± 1.2, SA: 12.86 ± 1.0)(p < 0.05). The IOP4 and IOP5 in the SA group were lower than those in the GA group. The IOP6 in both groups was higher (SA: 15.20 ± 0.8, GA: 16.50 ± 1.0) than the baseline IOP values, albeit not significant (p > 0.05). In prone position, IOP at the T4 and T5 timepoints were significantly higher than the initial values in both the SA and the GA groups; however, the increase in the GA group was more higher than that of the SA group. Conclusion: In intraoperative period, intraocular pressure may increase in both management of anesthesia, but this increase is higher in the general anesthesia group.