Neurogenic, Myogenic, Myasthenic and Painful Ptosis

Neurogenic and myogenic ptosis are uncommon but it is important to exclude these when assessing a patient with ptosis. Lid position, extraocular motility and the pupil should always be examined. Important factors to explore are ptosis variability, onset and duration, diplopia, headache, previous trauma or surgery, muscle weakness, general health condition and family history. Oculomotor Nerve Palsy (ONP) causes unilateral ptosis, mydriasis and limited adduction, supraduction, and infraduction. Pupil-involving ONP is often due to an aneurysm and immediate neuroimaging is vital. Pupil-sparing ONP is more often due to an ischemic microvascular cause. Horner's syndrome (HS) consists of mild ptosis, miosis, and lower lid elevation. Pain is almost always present when HS is due to carotid artery dissection but ptosis is mild, in contrast to cerebral aneurysm rupture as a cause, where ptosis is complete. In such acute situations, the prognosis is inversely proportional to diagnostic delay, and immediate imaging is mandatory. Myaesthenia gravis is an autoimmune neuromuscular disease with disturbed transmission from the nerve ending to the muscle. Typically, ptosis varies during the day, day to day and is often associated with diplopia. Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial myopathy causing slowly progressive paralysis of the extraocular muscles associated with progressive bilateral ptosis. Myotonic and muscular dystrophies are autosomal dominant disorders with gradually progressing ptosis and muscle weakness. A cautious approach to ptosis surgery is preferred as the facial and orbicularis muscles and Bell’s phenomenon are often impaired with risk of reduced eyelid closure and exposure to keratopathy post-operatively.