August 29, 2018
The beauty of disposable contact lenses is no cleaning or storage is required, and you’re guaranteed a fresh pair of contact lenses every day. The downside is many patients are flushing those lenses down the toilet, or washing them down the sink, causing environmental harm, according to reporting by Veronique Greenwood in the The New York Times.
Research presented last week at the American Chemical Society’s meeting in Boston showed that 20 percent of more than 400 contact wearers, who were randomly recruited in an online survey, flushed used contacts down the toilet or washed them down the sink, rather than putting them in the garbage, Greenwood reports.
When the lenses make their way to a wastewater treatment facility, they do not biodegrade easily, the researchers report, and they may fragment and make their way into surface water. There, they can cause environmental damage and may add to the growing problem of microplastic pollution. A 2015 study found that there were 93,000 to 236,000 metric tons of microplastic swirling in the ocean.
Filters keep some non-biological waste out of wastewater treatment plants, said Rolf Halden, the director of the Center for Environmental Health Engineering at Arizona State University, and Charles Rolsky, a graduate student and the study’s lead author. But contacts are so flexible that they can fold up and make their way through. The researchers interviewed workers at such facilities, who confirmed that they had spotted lenses in the waste.
The researchers then submerged contacts in chambers where bacteria are used to break down biological waste at a treatment plant. They found that even after seven days of exposure, the lenses appeared intact, though lab analysis detected small changes in the material.
Then, going through about nine pounds of treated waste, Rolsky and a colleague found two fragments of contact lens, implying that while microorganisms might not make much of a mark, physical processing might break them into pieces.
Tiny bits of plastic from many sources have been spotted in the oceans and other bodies of water, where they may be ingested by fish, corals and other animals. The fragments can carry high loads of pollutants absorbed from their surroundings, so the organisms get a dose of these substances as well.
The researchers noted that contact lens packages don’t yet tell patients how to dispose of the lenses. Is that something you can address with your patients?
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