Introduction
Plastic waste is a key issue. A current estimate assumes that around 4.8 to 12.7 million tons of plastic waste enter the oceans every year. However, only a small part swims on the surface, the rest is drawn into deeper waters or onto the sea floor. Many animal species are affected by plastic waste and even eat it and therefore the plastic enters the natural food chain (WWF, 2020). When using contact lenses, there is a lot of waste, which is not biodegradable because they are made of plastic. The use of contact lenses thus contributes to the single-use plastic problem. But how does this happen?
Problems
Contact lenses have been used for decades to correct vision. More than 150 million people use contact lenses today (Moreddu et al., 2019). According to a Statista survey , around 4.2 % of the Swiss population wore weekly or bi-weekly lenses in 2021 (Statista, 2022). Most modern contact lenses are made of silicone hydrogel. In addition, there are also older models which are manufactured as pure hydrogel contact lenses. Contact lenses improve the lives of many people (Wilhelmi, 2022). However, the issue of the plastic waste produced by contact lenses is often forgotten. The use of contact lens products by end consumers comprises 0.5 % of the total environmental waste (Morgan et al., 2003). The materials used to make contact lenses are different from other plastic waste. Most plastic waste from the contact lenses themselves and their packaging end up in the ocean or in landfill. Plastic can take up to 500 years to fully degrade in landfills or in the ocean (Optical Express, 2019). Optical Express surveyed over 3’000 contact lens users across the UK in 2019. The survey showed that 95 % of those surveyed discard their contact lenses in the trash or simply flush them down the toilet. Only 3% of people recycle their lenses (Optical Express, 2019). This is a huge problem. According to researchers, the bonds of the plastic polymers of contact lenses change in sewage treatment plants under the influence of microbes. However, the contact lenses are not degraded in this process. The contact lenses lose their structure and break down into smaller plastic particles, which lead to microplastics. Microplastics are small plastic pieces less than five millimeters long which can be harmful to our ocean and aquatic life (NOAA, 2021). Microplastics pollute the oceans and are eaten by marine animals and thus enter the food chain.
What can be done?
In principle, all contact lens waste can be recycled. Nowadays, a lot of materials science research is being done to better recycle plastic waste. Today’s recycling process is both time-consuming and expensive, as materials must be sorted first. Recycled plastic is often a poor-quality polymer that cannot be used for many materials today. New advances are being made towards chemically recyclable materials, which requires less energy.
Which Plastics Are Recyclable? (Contact Lens Spectrum, 2019)
The correct disposal of contact lenses and their packaging can be changed by the consumer and retailer. Consumers should never flush contact lenses down the toilet, otherwise the structure of the plastic will decompose in the sewage treatment plant and end up as microplastic. According to Optical Express 2 out of every 3 patients are unaware of the impact contact lenses have on the environment (Optical Express, 2019). Contact lenses should always be disposed in the trash can. Most packaging is made of cardboard and plastic, which can be recycled. Extended wear contact lenses, as opposed to daily, are better for the environment as they result in less plastic waste. Even better is choosing to wear glasses or eye laser surgery.
Bibliography
Moreddu R., Vigolo D., Yetisen Ali K., 2019. “Contact Lens Technology: From Fundamentals to Applications”. (Accessed 3 June, 2022)
Morgan Sarah L., Morgan Philip B., Efron N., 2003. “Environmental impact of three replacement modalities of soft contact lens wear”. (Accessed 3 June, 2022)
WWF, 2020. “Plastikmüll im Meer – die wichtigsten Antworten”. Online: https://www.wwf.de/themen-projekte/plastik/unsere-ozeane-versinken-im-plastikmuell/plastikmuell-im-meer-die-wichtigsten-antworten#:~:text=Das%20entspricht%20einer%20Lastwagenladung%20pro,etwa%2080%20Millionen%20Tonnen%20angesammelt (Accessed 3 June, 2022)
Statista, Stewart C., 2022. “Share of population aged 15-64 old who wear contact lenses in Switzerland from 2021, by type of lens”. Online: https://www.statista.com/statistics/431220/penetration-of-individuals-who-wear-contact-lens-by-type-of-lens-in-switzerland/ (Accessed 3 June, 2022)
Optical Express, 2019. “97% of contact lens users are damaging the environment”. Online: https://www.opticalexpress.co.uk/magazine/article/97-of-contact-lens-users-are-damaging-the-environment#:~:text=97%25%20of%20contact%20lens%20users%20are%20damaging%20the%20environment&text=Vast%20amounts%20of%20plastic%20are,ending%20up%20in%20the%20oceans. (Accessed 3 June, 2022)
NOAA, 2021. “What are microplastics?” Online: https://oceanservice.noaa.gov/facts/microplastics.html (Accessed 3 June, 2022)
Dougherty Laservision, 2022. “Contact lenses harming the environment”. Online: https://www.doughertylaservision.com/vision-blog/contact-lenses-harming-environment/ (Accessed 3 June, 2022)
Wilhelmi A., 2022. “Environmental Impacts of Contact Lens Waste”. (Accessed 3 June, 2022)
Contact Lens Spectrum, Yeung K., Davis R., 2019. “The environmental impact of contact lens waste”. Online: https://www.clspectrum.com/issues/2019/august-2019/the-environmental-impact-of-contact-lens-waste (Accessed 3 June, 2022)
Country Living, Avis-Riordan K., Cornish N., 2019. “Acuvue launches new eco-friendly way to dispose of your contact lenses”. Online: https://www.countryliving.com/uk/wildlife/countryside/a22797174/eco-friendly-way-dispose-contact-lenses/#:~:text=Now%2C%20Johnson%20%26%20Johnson%20Vision%20is,and%20foil%20packaging%20after%20use. (Accessed 3 June, 2022)