Ptosis is the medical term given to the condition of droopy eyelids. It is generally associated with an age-related sagging of the muscles that hold the eyelids up. However, ptosis can also occur in children as a congenital disability (congenital ptosis).
Ageing and sun exposure
Exposure to the sun and the natural effects of ageing can cause the skin around your eyes to sag more. As the skin becomes less elastic with age and the face becomes less plump and firm, the result is often loose or excess skin around the eyes.
Damage to the nerves that control the muscles around the eyes can also cause droopy eyelids to occur.
Disease or injury
Occasionally, certain diseases or an injury to the eye or eyelid can cause the eyelids to droop and sag.