Lid nystagmus evoked by ocular convergence: an ocular electromyographic study.

In 1916 Pick described a nystagmus-like movement of the upper eyelids in a young woman with a slowly progressive neurological disease characterized by pseudobulbar and cerebellar signs. Her lids were motionless as she looked in the distance but, as she focused on an approaching object, they jerked up and down in rhythmic motions that increased as convergence increased. The lids also elevated in irregular step-like jerks as she followed an upward moving object. Gaze-evoked ocular nystagmus was present but Pick stressed that the lid 'nystagmus' was a separate motor phenomenon, related particularly to convergence. There have been no further reports of this sign, which suggests that it is either extremely rare or difficult to recognize. The present report describes a case of lid nystagmus conforming to Pick's description and includes ocular electromyographic studies.