A woman putting a contact lens in her eye.

Approximately 45 million people in the U.S. wear contact lenses to correct their vision—and most of them go years without a problem. But contact lenses are not without their risks, some potentially dire.

“Wearing contact lenses can increase your chances of getting a severe eye infection,” says Jennifer Cope, M.D., a medical officer in the Waterborne Disease Prevention Branch of the Centers for Disease Control and Prevention, whose Contact Lens Health Week runs through August 24.

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In a report last year from the CDC, Cope and her team found that 85 percent of adolescent, 81 percent of young adult, and 88 percent of older adult contact lens wearers had at least one habit that increased their risk of eye infection.

“Common behaviors among all age groups that put them at risk for eye infection included sleeping in their lenses, not replacing contacts and cases as recommended, and swimming in their lenses,” Cope says.

If you use contact lenses, there’s no need to panic. “Overall, contact lenses are incredibly safe,” says Michael Goldstein, M.D., co-director of the cornea service at Tufts Medical Center in Boston. “But the biggest risk is the risk of infection, so you need to take the proper precautions.”

Though Goldstein says most infections are small and cause only some redness and discomfort, rare, more serious infections can lead to significant loss of vision

How to Wear Contact Lenses Safely

The best way to protect your eyes and preserve your vision is to be more conscientious about your contact lens care routine. Even careful contact lens wearers may not realize how much their habits are actually increasing their risk of eye infection.

We compiled these tips from the CDC and Goldstein to help you keep your eyes at their healthiest.  

  • Remove your contacts at the first sign of irritation. If your eyes are red, painful, or irritated, stop wearing your contacts immediately and see whether the problem clears up within a day or so. If it doesn't, see your eye doctor to make sure you get treated for any potential infection as quickly as possible.
  • Don’t sleep in your contacts. This is the leading risk factor for infection. In fact, according to the CDC, sleeping and even napping with your contact lenses in can increase your chance of infection by six to eight times. “The eyes need oxygen,” says Goldstein. “When they’re closed and you have the extra layer of a contact lens, it prevents the necessary oxygen from getting to the surface of the eye.”
  • Toss the lenses on schedule. If you wear contacts that are meant to be worn for a week or for 30 days, be sure to throw them away and use a new pair at those intervals. Using them longer than that allows bacteria to build up and increases your risk of infection.
  • Don’t rinse contacts with tap water. Tap water can contain parasites capable of causing a serious, vision-threatening eye infection called acanthamoeba keratitis. To be safe, it’s also best to avoid showering or washing your face while wearing your lenses (that same tap water can get in your eyes). And make sure your hands are clean and dry before handling your contacts.
  • Don’t swim while wearing them. Pool water can harbor the same infection-causing organism found in tap water. “And the parasites seem to especially thrive in the warm environment of a hot tub,” Goldstein says. Even if you don’t dunk your face underwater, you’re likely to get some water in your eyes when you rub your face or touch your eyes. If you do wear your contacts in a pool or hot tub, Goldstein recommends taking them out immediately afterward and either tossing them (if they’re disposables) or disinfecting them.
  • Use fresh solution daily. Never just top off your contacts case. To prevent bacteria from growing, completely empty the case every time you remove your contacts and refill it with fresh solution when you put them back in the case.
  • Swap out your contacts case frequently. Every time you finish a bottle of disinfecting solution, toss your old case and start using a new one.
  • Consider daily-wear contacts. “The overall safety profile of daily disposable contacts is better,” Goldstein says. The fact that you only handle them once (when you put them in); don’t ever have to rinse, disinfect, or store them; and can toss them after a single use eliminates many of risk factors for infection that are associated with contact lens use. The cost of the contacts themselves is slightly more than ones you wear for several weeks, but you save money by not having to buy any disinfecting solutions. “When you add it up, the cost isn’t much different,” says Goldstein. “And if it prevents even one mild infection, you’ve probably saved money.”