Ptosis is abnormal drooping of the upper eyelid due to weakness of the muscle that normally keeps the eyelid raised. The sagging lid may partly or totally close the eye.
One or both eyes may be affected. Ptosis is occasionally present from birth but is more common in adults.
It may be due to normal aging, or occur as a result of injury or a disease such as myasthenia gravis, which causes progressive muscle weakness.
Ptosis can be corrected by surgery to tighten the eyelid muscle