Reusable contact lenses more than triple risk of rare preventable eye infection

Medical Xpress / University College London / Ophthalmology ^ | Sept. 22, 2022 | Nicole Carnt et al

[ConservativeMind]

People who wear reusable contact lenses are nearly four times as likely as those wearing daily disposables to develop a rare sight-threatening eye infection.

The case control study identifies multiple factors that increase the risk of Acanthamoeba keratitis (AK), including reusing lenses or wearing them overnight or in the shower.

AK is one type of microbial keratitis (corneal infection)—a condition that results in inflammation of the cornea (the eye's clear protective outer layer).

Sight loss resulting from microbial keratitis is uncommon but Acanthamoeba, although a rare cause, is one of the most severe and is responsible for about half of those contact lens users who develop sight loss after keratitis. Up to 90% of AK cases are associated with avoidable risks, although the infection remains rare, affecting fewer than 1 in 20,000 contact lens wearers per year.

AK causes the front surface of the eye, the cornea, to become painful and inflamed, due to infection by Acanthamoeba, a cyst-forming microorganism. The most severely affected patients (a quarter of the total) end up with less than 25% of vision or become blind following the disease and face prolonged treatment. Overall, 25% of people affected require corneal transplants to treat the disease or restore vision.

People who wore reusable soft contact lenses (such as monthlies) had 3.8 times the odds of developing AK, compared to people who wore daily disposable lenses. Showering with lenses in increased the odds of AK by 3.3 times, while wearing lenses overnight increased the odds by 3.9 times. Among daily disposable wearers, reusing their lenses increased their infection risk.

With further analysis, the researchers estimated that 30-62% of cases in the UK, and potentially in many other countries, could be prevented if people switched from reusable to daily disposable lenses.

[ConservativeMind]

I still use the monthlies, but I use a gentle liquid hand soap (both no tears and no antiseptic type) and wash my contact lens bottle and lens case each time.

[ConservativeMind]

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[FamiliarFace]

I used hard lenses before the soft ones came out for probably 20 years. I got pink eye a number of times (before contacts and after), but that’s about the most problem I got from those lenses. I could never get used to the soft ones, either, so after hard contacts just wore my glasses until I had lasik performed.

[crusty old prospector]

I guess I’ll have a cane, a monkey, and a tin can soon. I have worn them for about 30 years.

[RomanSoldier19]

it always makes sense to show fingers into your eyes

[vpintheak]

Study brought to you by the companies that provide more expensive daily wear contacts… only half kidding.

[Nifster]

I’ve always worn hard contacts because of my prescription

[pfflier]

—a condition that results in inflammation of the cornea (the eye's clear protective outer layer).

This is from a medical institution?

The conjunctiva is the clear membrane that covers most of the eye, the cornea covers the area of the iris and pupil.

[higgmeister]

Isn’t this at least 35 years late?

[ChessExpert]

I wear my monthly contact lenses in the shower because I see better. However, I could easily stop.

For the last two months or so, my eyes have been mattering up like crazy. Sometimes I have to stop and blink several times in order to see clearly. It could be allergies, though I have not had this problem in prior years. I’ve made a point of soaping up my lens case every day.

Now days, I too have to wonder if the study is funded by the producers of disposable lenses. Whether it’s global warming, the Wuhan virus, or anything else, someone will produce the result that pays. I won’t say that all researchers/scientists are prostitutes, but some can certainly be found.

[Don@VB]

I’ve worn contact lenses (hard and soft) for fifty years. I’ve had a few minor infections, but always inconsequential. I’m currently using the monthly type. Best recommendation I can offer is to change them promptly or prior to the specified duration period. When I did have a problem it was usually my violation of that rule.

[bgill]

Notice glasses don’t cause those problems.

[Seaplaner]

I shower with my monthlies sometimes. I'm careful because some of the oils in soaps and shampoos can get into the plastic matrix and cloud them up a bit.

I'm careful to soak my lenses overnight in a peroxide solution. And, I'm careful to wash my paws in Ivory soap before sticking my lenses into my eyes.

I've used the same pair of lenses for a few months, on occasion. Typically, one month max.

Issues in roughly 2 decades? None.