When the upper eyelid droops over the eye, it’s called ptosis (pronounced “toe-sis”) and it happens to people of all ages.

Children may be born with the condition and adults may develop it with age. In between, it could develop as a side effect after certain surgeries or in rarer cases, diseases or tumors.

The most common cause of droopy eyelids is age-related stretching and weakening of the levator muscle tendon—one of the workhorses that lifts the eyelid. Considering that we blink some 15-20 times a minute, it’s not surprising that our eyelids might need a little help by the time they’ve reached a certain age.

Why is it a problem?

“It’s not just about looks,” notes John A. Moran Eye Center oculoplastic surgeon, Douglas P. Marx, MD. But that is one of the main reasons many adults opt for a relatively simple outpatient surgery to correct a droopy eyelid. Other issues include dry, gritty eyes, headaches brought on by straining the forehead muscle eye fatigue at the end of the day.

“Children born with ptosis have more challenges and risks associated with the condition than most adults do, so it’s important that they be carefully evaluated by an ophthalmologist early on,” he says. “In most cases, their ptosis is due to a levator muscle that has not fully developed.”

Ptosis is obvious when the eyelid droops or when the upper eyelid creases don’t line up with each other—or when a child tips his head back, lifts up his chin, or raises his eyebrows to try to see better. Over time, these movements can actually cause head and neck problems and put the child at risk for a host of vision problems.

If the child’s eye droops so much that it blocks vision, he can develop amblyopia (also called “lazy eye”). One eye will have better vision than the other. Ptosis can also cause astigmatism, causing blurry images. Crossed eyes are another risk.