Vertical saccadic velocity determination in superior oblique palsy.

Vertical saccadic velocities were measured in various horizontal gaze positions in patients with known superior oblique weakness and compared to similar measurements in a normal control group. Marked slowing of the down saccade in the adducted position occurred in the patients with superior oblique weakness and not in the controls. This suggests that it is possible to differentiate oblique and rectus function by saccadic velocity analysis.