Here’s How Revolting Your Contact Lenses Are

2 minute read

The magic clear disks that bring your world into focus may be doing some bad things to your eye bacteria, a new study suggests.

“The eye has a normal community of bacteria, expected to confer resistance to invaders,” says senior study investigator Maria Gloria Dominguez-Bello, PhD, associate professor of the Human Microbiome Program at New York University School of Medicine. But inserting contact lenses seems to mess with that delicate balance, the researchers found.

Read More: The Best Places to Buy Contacts Online: Our Top Recommendations

They wanted to compare the colonies of bacteria living on the eyeballs of people who wear contact lenses to the eyes of those who don’t, so they recruited 20 people in the new research, presented at the annual meeting of the American Society for Microbiology. They swabbed different parts of the eye, sequenced the bacteria and found major differences between lens-wearers and people who didn’t wear lenses. Bacteria inside the eyes of contacts-wearers looked more like the colonies of bacteria found on their skin than those normally found in eyes, compared to the normal bacteria of the lens-free group.

You Asked: Your Top 10 Health Questions Answered

You Asked: Are Cleanses Healthy?
You Asked: Are Cleanses Healthy? Potions that claim to clear your body of toxins might sound alluring, but do they deliver?Illustration by Peter Oumanski for TIME
You Asked: Is Dessert Bad For Me?
You Asked: Is Eating Dessert Really That Bad For Me? Bad news for sweet-eaters—except if you end your meals with this kind of treat.Illustration by Peter Oumanski for TIME
You Asked: What’s the Best Way to Whiten My Teeth?
You Asked: What’s the Best Way to Whiten My Teeth? Yes, teeth whitening actually works—but here's why you have to dish out major bucks to see results.Illustration by Peter Oumanski for TIME
You Asked: Is Meditation Worth It?
You Asked: Is Meditation Really Worth It? From easing stress to lowering heart disease risk, focusing your mind can do some amazing things for your body.Illustration by Peter Oumanski for TIME
You Asked: What’s the Healthiest Sweetener?
You Asked: What’s the Healthiest Sweetener? Take a taste of the unsettled science of sweeteners.Illustration by Peter Oumanski for TIME
You Asked: Should I Go Paleo?
You Asked: Should I Go Paleo? The pros and cons of eating like a caveman.Illustration by Peter Oumanski for TIME
You Asked: Is Cracking Your Knuckles Bad?
You Asked: Is Cracking Your Knuckles Bad? Here's what really happens to your joints when you snap, crackle and pop.Illustration by Peter Oumanski for TIME
You Asked: Is Running on a Treadmill as Good as Running Outside?
You Asked: Is Running on a Treadmill as Good as Running Outside? You'll fool your body into thinking it's outside with this one small treadmill tweak.Illustration by Peter Oumanski for TIME
You Asked: Does Laughing Have Real Health Benefits?
You Asked: Does Laughing Have Real Health Benefits? Here's proof that everybody could use a belly laugh.Illustration by Peter Oumanski for TIME
You Asked: What Is My Poo Telling Me?
You Asked: What Is My Poo Telling Me? If you listen hard enough, you'll hear all kinds of health stories from #2.Illustration by Peter Oumanski for TIME

That might be because finger skin bacteria lingers on the lenses, which is then transferred to the eye’s surface, suggests Dominguez-Bello. Another possible explanation: the lenses may favor skin-like bacteria over the kind normally found in the eye.

Either way, it doesn’t look good for lens-wearers, who had enriched communities of pathogens that play key roles in conjunctivitis, keratitis and endophthalmitis—all inflammatory eye conditions, says Dominguez-Bello. Using contact lenses has been linked to eye diseases and infections and is considered a risk factor for keratitis.

The study is too small and preliminary to warrant eye-care changes, but Dominguez-Bello calls for more research on the eye microbiome, a bacteria-rich community overlooked in the growing microbiome research focused on the gut and skin. “Despite being important in ophthalmology, the eye microbiome has been largely neglected, and its functions remain unknown,” she says.

More Must-Reads from TIME

Write to Mandy Oaklander at mandy.oaklander@time.com