Sleeping while wearing contact lenses almost seems like a rite of passage among people who wear them. But it is a dangerous habit that can increase your risk for vision loss. Nearly all contact wearers admit to at least one risky behavior that can lead to an infection, including 50 percent who say they have fallen asleep with their contact lenses in. Between 40 and 90 percent of the 41 million people in the United States who wear contacts do not follow the proper instructions for usage. Soft contact lenses, which reduce the wearer’s chance of complications, were introduced in 1971. However, only around 8 percent of contact lens users actually wear them.

“While some contact lenses are approved for continuous overnight use, sleeping in contact lenses that are not approved for overnight use does increase the risk of eye infections,” Dr. Melissa Barnett, from the California Optometric Association, told Medical Daily. “Contact lenses that are worn incorrectly can lead to serious concerns such as corneal infection, extreme pain, light sensitivity, and permanent vision loss. It is important not to sleep in contact lenses unless advised to by an eyecare provider."

Here are five risks associated with sleeping in your contact lenses.

Hypoxia of the Eye

Like every other part of our body, our eyes need oxygen to function. Since the cornea does not have its own blood supply, it takes oxygen from tears and the open air. Wearing contacts in general can cut off the supply of oxygen getting to the cornea. Wearing them when the lids are closed during sleep often leads to hypoxia , or a lack of oxygen. As hypoxia persists, the risks become more serious. One of those risks is the growth of new blood vessels, which may not seem all that threatening, but neovascularization, as it’s called, can result in some serious problems for contact wearers, such as loss of vision, especially if it grows longer than 2 millimeters.

Corneal Ulcers

Wearing contact lenses for too long significantly increases a person’s risk for corneal ulcers , open sores that form on the cornea. Contact lenses can damage the cornea in a number of ways if not properly cared for and changed out regularly. For example, they can scratch the surface of the cornea leaving it open to infection, microscopic particles can become trapped underneath them, bacteria can get on them when they are put back in cleaning solutions, and they can lead to hypoxia. Severe cases of corneal ulcers may require a corneal transplant using donor tissue.

“People who sleep in contact lenses are at a five times higher risk of developing corneal infections, which can permanently affect vision. [They] should only sleep in their contact lenses if approved by their optometrist, and they must follow the instructions for proper wear and care provided by the optometrist to minimize the potential for painful and sight-threatening complications,” Dr. Jeffery Walline, chair of the American Optometric Association’s Contact Lens and Cornea Section Patients, told Medical Daily.


Wearing contact lenses while sleeping for one night is understandable. We can all get a little forgetful at times. Wearing contacts for six months straight is extremely dangerous. Lian Kao , a student from Taiwan, found out the hard way: After keeping her contacts in for half a year, she was infected with Acanthamoeba — a single-celled amoeba that results in severe infection of the eye, skin, and central nervous system. While Kao refused to take out her contacts, the tiny parasite burrowed down to her cornea and began eating at the surface of her eyeball.

“Contact lens wearers are a high-risk group that can easily be exposed to eye diseases,” Wu Jian-Liang, the director of ophthalmology at Taipei's Wan Fang Hospital, told the Daily Mail . “A shortage of oxygen can destroy the surface of the epithelial tissue, creating tiny wounds into which the bacteria can easily infect, spreading to the rest of the eye and providing a perfect breeding ground. The girl should have thrown the contact lenses away after a month, but instead, she overused them and has now permanently damaged her corneas.”


Keratitis, an infection of the cornea, is the most common infection tied to contact lens use. In addition to Acanthamoeba , bacteria, fungi, and herpes all cause keratitis. Left untreated, all three can lead to minor vision loss, the need for a cornea transplant, and even blindness. The only way contact lens wearers can limit their risk for an infection is by practicing safe handling, storage, and cleaning. You can also avoid the possibility completely by purchasing one-day disposable soft contact lenses that should be thrown out after each wear.