Paralysis or weakness of the muscles that control
eye movements, and dilate
and contract the pupil. If there is only mild weakness, the earliest
symptom is double vision. If the muscles are actually paralyzed, it may be obvious to an observer that the eye does not move in certain directions.
can be produced by any condition affecting the muscles themselves or the nerves that supply them. Head injuries, stroke, meningitis, encephalitis, brain tumors, and diabetes mellitus are the usual causes. The condition
also occurs in hyperthyroidism
and myasthenia gravis. The treatment depends on the cause.