In the United States, over 30 million people wear contact lenses–that’s nearly 10% of the total population. However, despite how common contact lenses are, it’s very easy for their users to make mistakes with them; in fact, according to a recent study, 99% of contact users in the U.S. reported routinely making at least one risky or unsafe behavior with their contacts that could drastically increase their risk of eye infection. It’s easy to make mistakes when you don’t know what they are, so take a look at this list of some of the most common mistakes people make with their contacts!

Sleeping

While some contacts advertise themselves as “extended wear” and safe to wear while sleeping, there are still issues that arise when you keep your contacts on through the night. For one, the contact lens is a barrier that prevents oxygen from reaching your corneas, which they need in order to function properly. On top of that, your contacts can rip while you sleep and lead to irritation, discomfort, and potentially risk of serious infection. Be sure to take out your contacts before you go to sleep!

Showering or Swimming

Most water sources are home to a microorganism known as Acanthamoeba, and it can cause serious infections and even blindness. Since your contacts will absorb and retain water–which may or may not contain acanthamoeba–swimming or showering while wearing your contacts can drastically increase your risk of infection and blindness.

Cleaning Contacts with Tap Water

Acanthamoeba can live in tap water, so using it to clean your contacts can be another way of increasing your exposure to the dangerous microorganism and other bacteria. Additionally, since your contacts absorb and retain water, cleaning them in the tap can cause the lenses to become distorted and lose their shape.

Using Contacts Past their Expiration

Old contacts are a hub for germs, old proteins, solutions, and more, so wearing old contacts or lenses that are past their expiration date can mean applying a paradise of germs and spoiled fluids directly to your eyes; that’s practically an invitation for discomfort and infection. Make sure that you replace your contacts in a timely fashion when they expire.

Not Replacing the Case

Just like old contacts, the case for your lenses can become a petri dish of germs and expired solution–which will affect your lenses–if not properly cared for. Clean your case with solution at least once a day, and aim to replace the case every three months.