Contact lenses not environment-friendly

Turns out, if disposed off carelessly, the same contact lenses that help improve your vision could also end up affecting the marine life and ultimately your health.

According to a recent study, lenses could be contributing to microplastic pollution in waterways. Aquatic organisms can mistake these microplastics for food and since plastic is indigestible, this dramatically affects the marine animals' digestive system. Being part of a long food chain, some of these animals eventually find their way to the human food supply. This could lead to unwanted human exposures to plastic contaminants and pollutants that stick to the surfaces of the plastics.

Lenses that are washed down the drain ultimately end up in wastewater treatment plants. Researchers have estimated that around 6 to 10 metric tons of plastic lenses end up in wastewater in the U.S.

Contacts tend to be denser than water, which means they sink, and this could ultimately pose a threat to aquatic life, especially bottom feeders that may ingest the contacts.

Analyzing what happens to these lenses is a challenge for several reasons. First, contact lenses are transparent, which makes them difficult to observe in the complicated milieu of a wastewater treatment plant.

Further, the plastics used in contact lenses are different from other plastic waste. Contact lenses are 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, unlike polypropylene, that can be found in everything from car batteries to textiles.

These differences make processing contact lenses in wastewater plants a challenge. The study concluded that microbes in the wastewater treatment facility actually altered the surface of the contact lenses, weakening the bonds in the plastic polymers.

When the plastic loses some of its structural strength, it breaks into smaller plastic particles, which ultimately lead to the formation of microplastics. These microbes are ultimately exposed to the marine life.

With this initiative, the research team hopes that industries will take note and at the very least, provide a label on the packaging describing how to properly dispose of contact lenses, which is by placing them with other solid waste.

The full findings were discussed in the American Chemical Society 256th National Meeting.