LOS ANGELES (KABC) -- Millions of Americans wear contact lenses to correct their vision, but if they're not cared for properly, they can cause some serious eye infections.
Some contact lenses need to be switched out daily, others monthly. But the key is making sure they're not left in too long.
Thatiana Medina said she learned that lesson when she ended up with a scratch on her cornea.
"I forgot to take off my contact lens before going to bed," she said.
Consumer Reports Health Editor Jeneen Interlandi said Medina's not alone - that happens a lot.
"Falling asleep with your contacts in is a common problem. It can increase your chances of an eye infection by six to eight times," she said.
Even just a nap with your contacts in can be risky. Another safety tip is to never rinse your contacts with tap water. It's rare but it could contain a vision-threatening parasite.
For the same reason, don't swim with contacts unless you are wearing goggles and don't wear your contacts in a hot tub.
Another tip is you should not use week or monthlong lenses longer than recommended.
Contacts that you use for just one day are more expensive, but Consumer Reports said it might be worth it.
"Less handling can help make single-use lenses a bit safer than those you use multiple times," Interlandi said.
You also won't have to buy as much disinfecting solution with one-day lenses, and if you prevent just one infection you're ahead of the game.
Watch for trouble signs like redness, pain, or irritation.
Experts said you should immediately stop using the contacts and see an eye doctor if the problem doesn't clear up in a day or two.
How to avoid eye infections from contact lenses
CIRCLE OF HEALTH