Also known as ptosis or blepharoptosis, drooping of one or both upper eyelids can be an acquired or congenital condition. There are many different causes of drooping eyelids. It sometimes can be associated with eye movement abnormalities or pupillary problems. These include injuries, tumors, inflammation, and disease (such as diabetes mellitus, type 1 or type 2; myasthenia gravis; or Horner syndrome). In some cases, aging is the cause. The upper eyelid is normally lifted by the levator muscle; over the years, the attachment of the levator muscle to the lid may weaken. It is important to diagnose and treat the underlying cause of a drooping eyelid. Outpatient surgery under a local anesthetic is usually recommended to correct the problem.