"It's Bad": An Eye Doctor Is Warning People About This Common Habit That Could Ruin Your Eyesight

The human eye is a wondrous thing.

It is considered the body’s most complex organ after the brain and contains over 2 million working parts. About 80% of all learning happens through vision.

So how can we keep our eyes in tip-top condition? And what should we never do if we want them to stay as healthy as possible?

That’s what we — Raj Punjabi and Noah Michelson, the hosts of HuffPost’s “Am I Doing It Wrong?” podcast — asked Dr. Amanda Redfern, an ophthalmologist and assistant professor at Oregon Health & Science University’s Casey Eye Institute, when she recently dropped by our studio.

″[Sleeping with contact lenses in your eyes] is bad. It’s real bad. Don’t do it,” Redfern told us, adding that this even applies to naps. “It’s like a game of Russian roulette.”

That’s because you can get a corneal ulcer, which is an infection on part of the eye that a contact covers.

“It’s not going to happen every time, but when it happens, it’s terrible,” Redfern said. “It can be so bad you could, in really terrible cases, lose your eyeball.”

In less severe situations, Redfern said you could end up with a scar on your cornea.

“If that scar is in the center of your vision, that could affect your vision permanently, unless you get a corneal transplant,” she said.

Redfern also warned us not to engage in any activity that could cause lenses to become compromised or contaminated, including swimming in a pool or lake while wearing contacts or even showering with them.

“The problem with contact lenses is that it will sandwich bacteria between the lens and your cornea, and you can get infected and then have all the complications we talked about,” she said. “In general, we frown upon anything where your eye is going to expose to something nonsterile.”

That includes using tap water to rinse or store lenses.

When asked what she would suggest if someone were on vacation and forgot to bring contact lens solution, pushing them to choose between sleeping while wearing contacts or using tap water to store them, Redfern refused to pick either choice.

“Both of those are awful options,” she said. “I’d rather you [throw the contacts out] and just walk around a little bit blurry for the weekend.”

One thing Redfern does want us to do to keep our eyes healthy? Use eye protection more regularly.

“I always wear eye protection if I’m doing a house project where I’m hammering, sawing — anything where something can fly at my eye,” she said. “Always wear eye protection, because I actually spend half my time seeing hospital consults and the trauma that you see is just crazy.”

If you end up getting something lodged in your eye, don’t try to remove it yourself. Instead, tape a paper cup over your eye and immediately see a medical professional.

“Pulling it out in an uncontrolled fashion [could cause] the inner contents of the eye to come out with it,” Redfern said.

She also busted some myths about other activities that may be harmful or beneficial for the eyes (spoiler alert — reading in the dark isn’t going to ruin your vision), why we get floaters (and when we should see a doctor about them), and lots more.

Listen to the full episode wherever you get your podcasts.

For more information from Redfern, check out her Instagram page.

This article originally appeared on HuffPost.