Torsion and elevation under general anesthesia and during voluntary eyelid closure (Bell phenomenon)

The amount and interrelationship of ocular torsion and elevation was measured in 30 patients under general anesthesia; half received muscle relaxants (pancuronium bromide) during induction and half did not. Similar measurements were made in 20 patients during voluntary eyelid closure (Bell phenomenon). The mean amount of excycloduction was between 2.0 degrees and 2.5 degrees when the patients were under general anesthesia, whether or not muscle relaxants were used, and during voluntary eyelid closure. No statistically significant difference in the amount of torsion was found among the three groups. Elevation was significantly greater during voluntary eyelid closure (mean 5.3 mm) than during general anesthesia (p less than 0.01). No statistically significant difference in ocular elevation was found in patients under general anesthesia whether they were given a muscle relaxant (mean 1.5 mm) or not (mean 1.2 mm).