In recent years we've all become much more conscious of the impact our plastic consumption has on the world around us.
Plastic-free supermarket aisles and zero-waste shops are springing up with increased frequency, bans on common single-use plastic items like bags, straws and microbeads are being implemented, and campaigners are lobbying to discourage coffee chains from using disposable cups.
Earlier this year, the government even announced plans to introduce a "deposit return scheme" in England to crack down on plastic bottle waste.
Now scientists in the US have advised contact lens wearers not to flush away their used lenses in order to prevent them from ending up in the ocean.
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A study by Arizona State University found that 15-20% of contact lens wearers in the US dispose of their lenses by putting them down the sink or toilet.
Lenses disposed of in this way travel to wastewater plants and can ultimately make their way to the ocean, where they degenerate into harmful microplastics.
"Aquatic organisms can mistake microplastics for food and since plastics are indigestible, this dramatically affects the marine animals' digestive system," explained Varun Kelkar, one of the study's researchers.
"These animals are part of a long food chain. Some eventually find their way to the human food supply, which could lead to unwanted human exposures to plastic contaminants and pollutants that stick to the surfaces of the plastics."
Contact lenses are an increasingly popular option for people looking to improve their vision. It was found that 780 million contacts were sold in the UK and Ireland in 2016 – an 8% rise year-on-year. Some 65% of these 780 million were daily disposable lenses, while a further 31% were frequent replacement lenses.
The authors of the Arizona State University study said that lenses should be recycled where possible. If not, it's better to dispose of them alongside other solid waste than to try flushing them.
"The simple fix to this is for people not to put the lenses down the sink or shower or toilet!" another of the study's authors, Professor Rolf Halden, told the BBC.