Cardinal features of common underlying causes of ptosis

Cause	Levator function	Eyelid crease margin		Other clinical features
Congenital abnormality of the levator muscle*	Reduced	Crease often absent	Often unilateral	Many patients also have amblyopia, strabismus
Aponeurotic ptosis	Normal	Often increased	Uni- or bilateral	Isolated finding of ptosis
Cranial nerve 3 palsy	Reduced	Normal	Usually unilateral	Impaired extraocular movement in ipsilateral eye. If ipsilateral pupil dilated, urgent evaluation for aneurysm is required.
Horner's syndrome	Normal	Normal	Usually unilateral	Ipsilateral miotic pupil
Myasthenia	Reduced	Normal	Uni- or bilateral	Variable and fatigable. Diplopia and extraocular movement abnormalities often present.
Muscle disease	Reduced	Normal	Usually bilateral	Orbicularis oculi, other extraocular or bulbar muscles may be affected

Causes_of_ptosis.htm

* Other, less common causes of congenital ptosis are discussed in text.

Graphic 63515 Version 1.0