About 45 million people in the US wear contact lenses — and most of them do it wrong, according to a new study by the Centers for Disease Control and Prevention.
Almost 90 percent of US adults said they either slept with lenses, did not replace them as often as prescribed, or did some other dirty thing that would make your eye doctor lose it. The CDC would like you to stop: not wearing your contacts properly ups your risk of eye infections, and can even make you go blind.
There are a number of advantages to using contact lenses over glasses: lenses correct your vision and allow you to see all around, without slipping down your nose if you’re sweaty. Also, they don’t fog up when you enter a warm place in the winter, making you look like a dork. But if lenses are not cleaned or worn properly, they can lead to eye infections. Germs easily stick to the contact lens and can infect your eyes. If bacteria and viruses invade your cornea, you can have vision problems, or even lose your sight.
For this study, the CDC used a survey of over 4,500 US adults and over 1,600 kids ages 12 to 17 to check how they use contact lenses. They found that 85 percent of 12- to 17-year-olds (six in seven kids who wear lenses) reported at least one bad habit that increases their chance of an eye infection. Among adults, the percentage is even higher: 87 percent.
Here are the most common bad habits, according to the CDC:
- Sleeping or napping while wearing lenses
This is bad because it cuts off your cornea from receiving oxygen while you’re asleep, and it allows germs to fester in your eyes. Sleeping with contact lenses increases the chance of an eye infection by six to eight times, the CDC says.
- Swimming while wearing lenses
Pools are gross, the CDC found in 2016. And all those bacteria swimming around with you and your pals just love sticking to your contact lenses.
- Not replacing lenses as often as prescribed
Some contact lenses are daily and disposable, others are reusable for two weeks or a whole month. In any case, if you wear lenses longer than you’re supposed to, it can lead to a build-up of germs and gunk in your eyes.
- Not regularly replacing storage cases
Storage cases should be replaced at least every three months, according to the American Academy of Ophthalmology. Yes, that’s because cases contain bacteria that can contaminate your lenses, and your eyes.
- Topping off contact lens solution in the storage case
That’s when you add new solution to the existing one that’s been basking in the case for a while instead of emptying it out. Guess why that’s bad? Germs.
- Storing lenses in tap water
Tap water can be safe enough to drink, but it’s still filled with microorganisms that can attach to your lenses and infect your eyes.
- Not visiting an eye doctor at least once a year
If you don’t get regular eye exams, you won’t know if the lenses are hurting your eyes and you should start wearing glasses.
So, what are the best practices? Pretty much, just be clean. Always wash your hands with soap before handling your contacts, use solution to clean your lenses and case, replace your case regularly, and don’t wear lenses for longer than you should.
Oh also, use one contact lens per eye — lest you end up with 27 of them blurring your vision.
Update November 1st 5:58PM ET: This article was originally published on August 17 , 2017 and has been updated to include video.