Disorders of the Eyelids and Pupils

Abstract

Ptosis most commonly is caused by a lesion of the oculomotor nerve, oculosympathetic nerves, or neuromuscular junction. Soft tissue disorders in older adults are important causes of ptosis. Blepharospasm produces tight closure of the eyelids and can be differentiated from eyelid-opening apraxia by finding sustained contraction of the orbicularis oculi.

The first step in localizing anisocoria is to determine whether the dysfunction is in the sympathetic or parasympathetic innervation of the pupil by observing pupillary reactions to bright light. Sympathetic dysfunction produces a Horner syndrome which can be localized with a detailed understanding of the oculosympathetic tract. It is critical to recognize anisocoria due to parasympathetic dysfunction, because it is associated with life-threatening lesions such as posterior communicating artery aneurysm and uncal herniation.