ptose

Ptose, or ptosis, refers to drooping or sagging of the upper eyelid. It is most commonly discussed in ophthalmology, where eyelid ptosis can be congenital or acquired. Ptosis may impair vision if the droop covers the pupil, and individuals may compensate by elevating the brow.

Classification and causes

Ptosis can be caused by dysfunction of the muscles that elevate the eyelid, by nerve problems, or by structural changes. Major categories include myogenic (muscle disease such as myasthenia gravis or congenital muscle hypoplasia), neurogenic (nerve disorders such as oculomotor nerve palsy or Horner syndrome), aponeurotic or involutional (detachment or weakening of the levator aponeurosis associated with aging), mechanical (lid masses or swelling increasing weight of the eyelid), and traumatic (injury to the eyelid or surrounding tissues). Congenital ptosis is present at birth and often results from developmental abnormalities of the levator muscle; acquired ptosis develops later in life due to the above mechanisms.

Symptoms and examination

Patients typically present with a visibly lowered eyelid that may obscure part of the pupil or crease. Evaluation includes measurement of the margin reflex distance (MRD1), assessment of levator function, eyelid crease position, and the amount of eyelid closure. A full neuro-ophthalmic exam is performed to identify underlying causes such as myasthenia gravis, aneurysms, or nerve palsies. In suspected systemic or neurologic conditions, additional testing or imaging may be indicated.

Treatment and prognosis

Management depends on cause and functional impact. Underlying diseases (eg, myasthenia gravis) are treated accordingly. For eyelid-specific ptosis, surgical options include levator advancement/resection for good levator function, or frontalis suspension (slings) using autologous tissue or synthetic materials when levator function is poor. Mild or non-vision-impairing ptosis may be observed or managed with non-surgical aids such as a ptosis crutch. Prognosis varies with etiology and treatment; congenital ptosis carries risk of amblyopia if vision is obstructed.