Ptosis is also called "drooping eyelid." It is caused by weakness of the muscle responsible for raising the eyelid, damage to the nerves that control those muscles, or looseness of the skin of the upper eyelids.
Causes, incidence, and risk factors
Drooping eyelid can be caused by the normal aging process, a congenital abnormality (present before birth), or the result of an injury or disease.
Risk factors include aging,