Blepharoptosis (eyelid ptosis) is when the upper eyelid falls below its normal position. When the eyelid falls to the pupil, ptosis can cause loss of the superior visual field or more extensive vision loss. It may also cause astigmatism if it changes the shape of the cornea. Patients may complain of having to manually lift their eyelid in order to see. 

The eyelid can droop for a variety of reasons: a dehiscence of the levator muscle from the structural tarsal plate, a mechanical growth or swelling, muscle weakness, a neurologic deficit, or trauma. 

Blepharoptosis can be congenital or acquired. Congenital blepharoptosis is usually due to an embryologic failure of development or weakness of the levator muscle. Careful examination of young patients is important to exclude various syndromes such as Marcus Gunn jaw-winking syndrome.  

The most common form of blepharoptosis presents in the elderly and is due to the dehiscence of the levator aponeurosis insertion. This disinsertion may be attributable to a stretching of tissues with age, or it is sometimes associated with trauma, such as previous eye surgery where an eyelid speculum was used. These patients often have an elevated lid crease with a gradual lowering of the resting eyelid position. The levator function is typically normal.  

An acute onset of blepharoptosis associated with headache, pupillary dilation, or extraocular dysmotility is suggestive of cranial nerve involvement. Mild blepharoptosis associated with miosis of the ipsilateral eye indicates Horner syndrome, which affects the sympathetic pathway.