Although contact lens pollution is a concern, it is dwarfed by the eight million metric tons of larger plastic that clogs our oceans every year.
The calculation of how many lenses end up in our wastewater plants and habitat hinged on a variety of data sources.
Mr Kelkar said: 'When the plastic loses some of its structural strength, it will break down physically.
The ASU research team is presenting their results today at the 256th National Meeting and Exposition of the American Chemical Society (ACS), held in Boston from August 19-23. These animals are part of a long food chain. "We'd love to have a dialogue [with manufacturers] and establish a solid protocol for consumers to dispose of or even recycle their contact lenses", Rolsky says. "This is a pretty large number, considering roughly 45 million people in the USA alone wear contact lenses, amounting to 1.8-3.36 billion lenses flushed per year, or about 20-23 metric tons of wastewater-borne plastics annually".
To make matters worse, because contact lenses are typically denser than water, they can sink into aquatic zones and be eaten by marine life thriving down there, which can potentially poison them.
The next part of the research was to figure out what happens to those lenses.
Wastewater treatment facilities in the US simply don't do a good enough job of filtering out the tons of contact lenses that are disposed of through the sewer system, according to new research presented Sunday at the American Chemical Society's meeting in Boston. Further, the plastics used in contact lenses are different from other plastic waste, such as polypropylene, which can be found in everything from vehicle batteries to textiles.
Flushing contact lenses contributes to water pollution, study says
Contact lenses are frequently made with a combination of poly (methyl methacrylate), silicones and fluoropolymers to create a softer material that allows oxygen to pass through the lens to the eye.
Once sewage laden with contact lens fragments is pumped onto soil it may seep into the environment in different ways, the researchers say.
These differences make processing contact lenses in wastewater plants a challenge.
Researchers in the United States have been investigating the final journeys taken by disposable contact lenses.
The researchers found that contact lenses are so flexible that they can sometimes slide through the physical barriers meant to filter out nonbiological waste at treatment plants.
Some eventually find their way to the food supply, which could lead to people being exposed to plastic contaminants and pollutants that stick to the surfaces. Next the researchers surveyed more than 400 contact lens users about how they dispose of the products, finding that 21 percent discard their lenses down the toilet or sink. Perhaps they could start putting a label in the packaging of contact lenses that details proper disposal methods, said Rolf Halden, one of the authors. Halden mentions, "Ultimately, we hope that manufacturers will conduct more research on how the lenses impact aquatic life and how fast the lenses degrade in a marine environment".