Effect of general inhalational anesthesia on intraocular pressure measurements in normal and glaucomatous children.

Purpose: To investigate the agreement between the intraocular pressure (IOP) measurements in the awake condition and under different stages of general inhalational anesthesia using sevoflurane in both glaucomatous and normal children.

Methods: A prospective study was performed on 43 glaucomatous children and 30 age-matched controls. Baseline IOP of one eye was measured immediately before general anesthesia using Perkins tonometer and then re-measured under light, intermediate, and deep anesthesia, and then after intubation. Depth of anesthesia was determined using bispectral index pediatric sensor. The agreement between the IOP measurements before and during different stages of anesthesia was analyzed using Bland-Altman plots. Systematic and proportionate deviations between the IOP measurements were analyzed.

Results: The mean age was 58.6 ± 41.99 months. The mean IOP was significantly lower at all stages of anesthesia in both groups. The coefficient of variation was over 20% in all measurements under anesthesia. For all IOP measurements during anesthesia, the limits of agreement were > 7 mmHg difference in the control group and > 20 mmHg in the glaucomatous group. The best agreement was with the IOP measurement after intubation (mean limit of agreement of -1.4 mmHg, 1.96 s range, -8.8-6 mm Hg) in the control group and with the IOP measurement under intermediate anesthesia (mean limit of agreement of -4.2 mmHg, 1.96 s range, -15.1-6.8 mm Hg) in the glaucomatous group.

Conclusions: Inhalational anesthesia has variable effects on IOP measurement at all stages of anesthesia. Caution should be taken when extrapolating the true IOP from these measurements.