What docs found when they studied eye surfaces of contact lens users

Keep contact lenses clean eye doctors
Eye doctors are urging consumers to be scrupulous about cleaning and caring for their contact lenses. THE CANADIAN PRESS/AP/Tony Dejak

New York researchers are warning those who wear contact lenses daily: your eyes are vulnerable to infections and inflammation, and they don’t share the same bacteria as people who don’t wear contacts.

After studying the eye surfaces of handfuls of patients, New York University microbiologists say that contact lens wearers carry three times more bacteria than their counterparts. This could explain why the group is prone to serious eye infections.

“Our research clearly shows that putting a foreign object, such as a contact lens, on the eye is not a neutral act,” the study’s senior investigator, Dr. Maria Gloria Dominguez-Bello, said in a statement.

“What we hope our future experiments will show is whether these changes in the eye microbiome of lens wearers are due to fingers touching the eye or from the lens’s direct pressure affecting and altering the immune system in the eye and what bacteria are suppressed or allowed to thrive,” she explained.

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READ MORE: Eyeball-eating amoeba? 5 things contact lens users need to know

This was based on a small study, though: the scientists carried out a thorough genetic analysis on the eye surfaces of nine contact lens wearers and 11 participants with healthy eyesight.

For those who wear contacts, the micro-organisms that make up the microbiome on the eye – kind of like the eye’s ecosystem – share a lot of the same bacteria as the eyelid skin.

The researchers say that after soft contact lenses were introduced in the 1970s, rates of corneal ulcers climbed. Their guess is that germs from the skin – either from our eyelids or from poor hand hygiene – could be the culprit.

The findings, presented Sunday night in New Orleans, are reminding contact lens wearers to heed their optometrists’ advice: play by the rules if you’re wearing contacts and make sure you give your eyes a break every few days.

READ MORE: Prolonged contact lens use leads to corneal issues for Bedford man

“A lot of people think the eye itself is very clean but the reality is there’s a lot of bacteria and other organisms on the eye. Our eyes are able to deal with it as long as their defensive systems are working but when contacts are overused or worn overnight, it compromises the ability for the eye to deal with these problems,” Dr. Joe Chan told Global News last year. He runs a private practice and is member of the Ontario Association of Optometrists.

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When you’re wearing contacts, the amount of oxygen that gets to your cornea is limited. While some lenses are designed for overnight wear, some experts still recommend against wearing them to sleep.

“Leaving them on too long can leave the cornea starved,” Chan explained. In response, excess blood vessels can form in an attempt to supply oxygen and nutrients, and in the long run, they can obscure vision.

READ MORE: Student whose corneas eaten by amoeba a cautionary tale for contact lens wearers

Stick to wearing your contacts for about 12 to 16 hours at most, and take them off at night to give your eyes a break. If you wear them throughout the week, give your eyes a rest day on the weekend, too.

“That break gives [eyes] time to regroup, heal, and strengthen the immune system in that area,” Chan said.

READ MORE: Contact lens abuse – why we do it and the potential dangers

You’ll know if something’s wrong: your eyes will be red, irritated or dry. You could have chronic redness, sensitivity to light and eye pain. You could even encounter changes to vision.

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