Ptosis refers to a droopy upper eyelid due to insufficient opening of the eyelid. Ptosis can be unilateral or bilateral, depending on the cause. The normal position of the upper eyelid is at the upper border of the pupil, or just above the pupil, and both eyelids should be at the same level. The levator, innervated by cranial nerve III, is the major muscle involved in eyelid opening. Muller’s muscle, innervated by the sympathetic fibers ascending on the internal carotid artery is a minor contributor. Common causes are Horner’s Syndrome, Third Nerve Palsy, Myasthenia Gravis, aging and eye surgery such as cataract extraction.
References and Readings
- (2016). Walsh and Hoyt’s clinical neuro-ophthalmology: The essentials (3rd ed.). Philadelphia: Lippincott Williams & Wilkins.Google Scholar