The recommended wear time varies by type, but generally, colored contacts have even less longevity than corrective ones. And they're definitely not safe overnight. It also goes without saying that colored lenses are one-size-fits-one — not one size fits you and your BFF, too. "I've seen kids — largely teenagers — who share lenses like they would makeup or handbags," Dr. Steinemann says. "Sharing lenses is sharing germs and it's really, really dangerous."

Even if you dabble with the trend just once, it's still important to take the process seriously. Dr. Steinemann says infrequent wearers are most vulnerable to complications. "Even if you only [wear them] on weekends, for a party, or once in a blue moon, those are the people we worry about a lot," he says. "Lenses sitting around in cases are breeding grounds for infection. Before you put them in, always run them through a fresh disinfection cycle."

Going Forth

Before you start imagining how unique you'd look with whatever novel eye color you're after, Dr. Steinemann suggests asking yourself: Are you ready for this type of commitment? Or would a few streaks of pink hair or a tube of black lipstick satisfy the same urge? Because, though it might appear to be all fun and games, it's actually a serious and kind of fussy health commitment. "Just like correcting your vision with contacts, colored lenses require a certain amount of maturity and responsibility on the part of the wearer," he says.

Which is not to say just because you can buy cigarettes that you'll do a good job, he stresses. "I know teenagers who are very responsible and I know 30-years-olds who are very irresponsible. All I'm saying is, taking care of contacts — and taking care of your eyes — is really, really important."