Why you should never flush your contact lenses down the toilet

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Kayleigh Dray
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Woman wearing contact lenses

Do you flush your contacts? Here’s why you need to stop.

The number of people who wear contact lenses in the UK has risen steadily over the last 20 years; according to new research, nearly 3.5 million people now use contact lenses to correct their vision.

When it comes to disposing of our lenses, though, it seems a lot of us are doing so improperly – either by tossing them down the sink or flushing them down the toilet.

So, why is this such a big problem? Because it is contributing to the microplastic pollution crisis.

In a survey of 409 contact lens wearers, about one in five responded that they flushed them down the toilet or sink instead of throwing them in the trash, according to a new study presented at the American Chemical Society’s National Meeting and Exposition.

“We found that 15 to 20% of contact wearers are flushing the lenses down the sink or toilet,” said Charlie Rolsky, an Arizona State University Ph.D. student who is presenting the work, in a press release.

The flushed lenses, which are mostly plastic, turn up at wastewater treatment plants and become part of sewage sludge that gets spread on farmland. This, in turn, can contaminate the soil environment and become ingested by earthworms when it’s spread on land – creating a pathway for plastics to enter the food chain.

Similarly, rainfall can drive the wastewater into streams and other waterways, causing microplastic to end up in the ocean.

Rolf Halden, the director of the Biodesign Institute at Arizona State University and one of the authors of the new study, added that these contacts do not decompose.

“They don’t degrade. They don’t attenuate but they become smaller. So they create what we know as microplastic pollution, which is contaminating the oceans,” he said.

Halden went on to add that many people don’t think of the lenses as plastic waste because they feel like fluid, almost like water. They even come in tiny packets of saline solution.

But even people who describe themselves as environmentally conscious admitted flushing their lenses, he noted.

“We have created an almost immortal material. It does not go away. It does not biodegrade,” Halden said.

Rolsky hopes that the findings encourage people to think more about how to get rid of plastic waste.

“This might have been a different experiment had there been labelling on a lot of these boxes sort of specifying ‘maybe dispose of these with solid waste and please avoid having them go down a drain’; maybe it would be a different story,” he said.

He and his fellow researchers have advised that, going forward, contact wearers throw their lenses in the trash or recycle them.

The microplastic pollution crisis was brought to the public’s attention last year, during an episode of Sir David Attenborough’s Blue Planet (see above).

In it, the legendary documentary maker warned: “For years we thought the oceans were so vast and the inhabitants so infinitely numerous that nothing we could do could have an effect upon them.

“But now we know that was wrong.”

Since then, we have been treated to a horrifying roll call of plastic facts: by 2050 there will be as much plastic in the ocean as fish; a million plastic bottles are bought around the 
world every minute; a sperm whale found dead near Spain was found to have been killed by gastric shock after ingesting 
29kg of plastic waste; microplastic from Scotland has been detected in Antarctica.

In short, plastic – specifically single-use plastic – is really starting to trouble us. Thankfully, though, the crisis has had one positive impact on our world: it has brought thousands of people together and united them in the pursuit of one common goal – saving our planet.

With this thought in mind, we have created our ultimate guide on how to quit plastic. Be sure to read it here

Image: Peter Fogden / Unsplash


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Kayleigh Dray

Kayleigh Dray is Stylist’s digital editor-at-large. Her specialist topics include comic books, films, TV and feminism. On a weekend, you can usually find her drinking copious amounts of tea and playing boardgames with her friends.