Functional paralysis of horizontal gaze.

A 52-year-old steelworker displayed a consistent defect in leftward voluntary gaze across the midline. Both fast (saccadic) and slow (pursuit) eye movements were affected. Neuro-ophthalmologic evaluation revealed no additional neurologic or ophthalmologic deficit. Pupilary miosis occurred during leftward gaze attempt, indicating that the gaze palsy was due to spasm of the near reflex. Special maneuvers during clinical eye movement testing disclosed full ability to make normal horizontal fast and slow eye movements despite the apparent defect in "voluntary" leftward gaze.