Abnormalities of eyelid position and function.

Evaluation of the eyelids is an important part of the neuro-ophthalmic examination. Abnormal eyelid position and function can be caused by disorders involving the third cranial nerve, the oculosympathetic pathway, and the seventh cranial nerve, as well as supranuclear pathways, or as a result of neuromuscular diseases. To avoid unwarranted neurological investigations, it is also important for the clinician to recognize non-neurological eyelid abnormalities (such as ptosis from levator dehiscence or eyelid edema).