Ptosis

The abnormal descent or prolapse of an organ or anatomical part, most commonly the upper eyelid, resulting in palpebral drooping due to dysfunction of the levator apparatus or its neural supply. Possible causes are age-related aponeurotic ptosis, congenital ptosis, nerve damage (stroke, brain tumor, aneurysm, diabetic neuropathy, Horner syndrome), myasthenia gravis, muscular dystrophy, trauma, previous surgery, and long-term wear of rigid contact lenses may stretch the eyelid tissue.