What happens if you open your eyes underwater with contacts in?

Case of Missing Lens: Consider wearing swim goggles so that you don't find yourself starring in the "case of the missing lens" [a nancy drew mystery?]. I know people who swear that they've never lost a lens when swimming in a pool. But usually goggles are cheaper than replacing contact lens. If it doesn't float off your eye, it could pop out when you're wiping your face.

Lose your lenses: They will likely float out and be lost. You will at the very least expose your lenses to water borne organisms and parasites that can cause serious eye infections. Swimming in contact lenses, even in chlorinated water, is not recommended. I tell my patients that if they swim in contacts to then immediately discard them.

Possible infection: The contacts may float away. However, you should not wear contacts while swimming, as they may cause the development of a severe infection by a one celled organism called acanthamoeba. These infections are very difficult to cure and may cause severe scarring. Acanthamoeba lives in natural bodies of water, swimming pools, and hot tubs, even when properly chlorinated.