Ptosis is the medical name for the drooping of the upper eyelid, which can happen in one or both eyes.
A droopy upper lid can interfere with vision by affecting the top part of your visual field. You might also have difficulty keeping your eyelids open, eye strain or eyebrow ache (from the increased effort needed to raise your eyelids), and fatigue, especially when reading. For some patients, ptosis poses a cosmetic problem.
Ptosis can either be present at birth (congenital), or appears later in life (acquired), following long-term contact lens wear, trauma, after cataract surgery or other eye operations. There are less common causes of a droopy eyelid, such as problems with the nerves or muscles.