Apraxia of lid opening.

We describe eyelid movement abnormalities in an 80-year-old man with apraxia of lid opening (ALO), resulting from involuntary levator palpebrae inhibition (ILPI) and pretarsal orbicularis oculi (OO) contraction. He was unable to open his lids at will following closure. Attempted eye opening resulted in forceful contraction of the frontalis muscle, backward thrusting of the head and lengthened lid closure. The inability to reopen the lids was not evident during spontaneous reflex blinking and he had no difficulty in keeping the lids open once they had been manually lifted up. There were no episodes of involuntary drooping of the eyelids or spasmodic contraction of the OO causing involuntary eyelid closure. Pursuit eye movements were not restricted, the vestibulo-ocular reflex was preserved and both horizontal and vertical saccades were normal. Despite the clinically visible persistence of pretarsal OO activity, treatment with botulinum toxin injections in the pretarsal and preseptal portions of the muscle did not reduce his difficulty in initiating lid elevation but he found some benefit using lid crutches. ALO is thought to be due to an abnormality in the supranuclear control of eyelid movement. ILPI can present either isolated or combined with blepharospasm. The excitatory levator palpebrae response necessary to lift the lids up is likely to be in very close connection with the OO antagonistic inhibitory response. Alterations in one or another pre-motor structure may result in inability to raise the lids due to inhibition of the levator palpebrae as well as persistence of the pretarsal OO.