The condition often presents first with the head nodding, which is out of syncrony with the speed, direction, and tempo of the nystagmus. The condition lasts several months to years and usually fades by age 5 years. The nystagmus has a pendular quality. The direction of the nystagmus can be horizontal, vertical or rotatory and may vary with the direction of gaze. Spasmus nutans has occasionally been associated with developmental abnormalities or optic chiasm gliomas, therefore a CT scan should be obtained before reassuring the parents of the benign nature and favorable outcome of the disorder.
Ptosis is due to dysfunction of the muscles that elevate the eyelid.
A drooping eyelid may represent pseudoptosis from swelling of the eyelid caused by local edema or active blepharospasm. True ptosis results from weakness of the eyelid muscles or interruption of its nerve supply. Ptosis may also occur in myasthenia gravis, botulism, and some muscular dystrophies. Neurologic causes of ptosis include the Horner s syndrome, which results from the interruption of the sympathetic supply to Muller s smooth eyelid muscle, and third nerve palsy which innervates the levator palpebral muscle. Some diseases of the maculae or optic nerves affect one side more than the other.