Contact Lenses and PFAS

I had my first patient ask me about new research questioning the presence of PFAS chemicals in contact lens materials only two days after first learning of the news myself from the American Optometric Association newsletter. This article will likely continue to be updated as more research is published, but with more and more news outlets picking up the discussion, I thought it important to start a conversation written by a doctor to help better contextualize what we know, what we don't, and to pool together some broader research on contact lenses and their chemical make up. 

What is this new research?

The study in question was performed by researchers in partnership with Environmental Health News and published on the Mamavation website- a group dedicated to finding possible toxic or hormone-disrupting chemicals in every day products. They sent 18 different popular soft contact lenses to an EPA-certified lab and ALL contact lenses tested were positive for organic fluorine which the research team explained "is linked to the presence of PFAS molecules".

What are PFAS and Why Should we Care?

Since the 1950s, per- and polyflouroakyl substances (or PFAS) have been used in manufacturing in many every-day products, from cookware to plastics to clothing. There are thousands of different types of these molecules used in manufacturing, made up of chains of carbon and fluorine atoms which are long lasting and strong to help accomplish a variety of goals like improve product durability, resist stains, and make products more resistant to heat, oil, or water damage. According to the US EPA there are roughly 9,000 different types of PFAS molecules that humans are exposed to every day in our water, air, soil, and food, and in fact a 2015 study found that 97% of Americans have PFAS in their blood. Unfortunately we are just learning what all of this PFAS exposure might do to our environment and the health of the humans, animals, and plants living within it. The National Institure of Enivonmental Health Sciences (NEIHS) has and is conducting research to learn more; to date studies have reported "there are possible links between human exposure to PFAS and altered metablolism, fertility, reduced fetal growth, increased risk of some cancers, and reduced ability of the immune system to fight infections."

PFAS in Contact Lenses

Europe has in many ways led the way in environmental safety and recognition of the dangers of toxic chemicals. For example, the EU bans more than 1,300 chemicals used in everyday cosmetics as potentially hazardous; the United States bans only 11. Upon researching this article, I discovered that European doctors had been researching the effects of removing PFAS present in rigid gas permeable contact lenses due to a proposed ban of PFAS materials. Their research found extremely detrimental results on the comfort, breathability, and safety of contact lens wear with non-fluorinated materials. In contact lens manufacturing, fluorinated molecules are used to increase the oxygen transmission (breathability) of contact lenses, stability and durability of the contact lens material, and the ability to resist surface deposits of lipids and proteins. When the fluorinated materials were removed in favor of non-fluorinated materials, the result was an unsafe 87% reduction in oxygen transmissibility. The researchers proposed that "at this time there is no acceptable substitute for fluoro-silicone acrylates [in modern contact lens materials] to achieve the combination of high oxygen transmission rates, acceptable wettability and wearing comfort, mechanical structure and stability, and deposit resistance." 

Another point raised by European researcher Dr. Dmitry Mirsayafov in response to this discussion was that the PFAS used in contact lens manufacturing are hard molecules; not water soluble. So the question becomes just how much is it possible for them to be absorbed into the environment or the human body? 

According to research published by the National Institutes of Health, "human exposure to PFAS occurs through ingestion of contaminated drinking water and seafood, inhalation of indoor air, and contact with other contaminated media." Drinking water contaminated with water soluble PFAS has been cited as the "most substantial" source of PFAS exposure. I could not find any research regarding how hard molecule PFAS like those found in contact lens materials could be absorbed through a human eye while wearing a contact lens in writing this article, though hopefully this is a subject that will be researched by someone going forward.

Still More Questions

To turn back to the research on US soft contact lenses published by Mamavation, the study was done to test the presence of fluorine in contact lens materials, which per the researchers was "likely to show the presence of PFAS". The researchers disclose this importantly to remind you that the test results they are sharing are not the presence of PFAS themselves, and it is important to keep that in mind as they report their results. As an optometrist I found the results very confusing because lenses of the same material had very different fluorine results published. For example Acuvue Oasys 1 Day (Senofilcon A) was listed in the "not one of our favorite" contact lens categories for having higher amounts of detected fluorine, but Acuvue Oasys 2 week (also Senofilcon A) was listed as "one of the best contact lenses" for having low amounts of detected fluorine. Similarly, Dailies Total 1 spherical was listed in their medium tier  fluorine level labeled "better contact lenses", while Dailies Total 1 toric and multifocal were listed in the lowest fluorine level "one of the best contact lenses" tier. Yes, they are all Dailies Total 1 (delefilcon A), just with a different prescription in the lens.

The researchers made no attempt to explain why the same contact lens materials were testing with such big differences within their own study, it did make me question just what was truly being revealed since the same lens material that was "one of the worst" was also "one of the best". 

The Response

Due to these unexplained discrepancies in the published research, manufacturers of contact lenses have challenged the results and its implications to the millions of contact lens wearers worldwide. An Alcon representative stated that the company "questions the results of that report. For example, Dailies Total1 and Total30 contact lenses do not contain organic fluorine in their formulation. Alcon is requesting a copy of the report to better understand how it reached its conclusions." 

A spokesperson for CooperVision said, “PFAS (per and polyfluoroalkyl substances) may be used in a wide range of products for important chemical and physical properties. Like thousands of other companies, we are learning as much as possible about this issue—and are committed to acting responsibly in the interests of our customers and sustainable practices.
 
"In addition to significant speculation and opinion masked as science," the CooperVision spokesperson said, "the blog post creating this discussion tested a marker, which it readily admits is not a direct assessment of PFAS inclusion. We have not been provided with its data and have not been contacted by the organization. There are multiple definitions of PFAS around the world, with no universal consensus.”

The Contact Lens Institute released this statement: "The Contact Lens Institute is aware of a recent blog post regarding our category that is prompting news reports and social media discussion. Soft contact lenses—which are recognized medical devices—are required to meet rigorous health and safety standards and are reviewed by FDA prior to clearance for U.S. sale. It’s important to remember they have demonstrated safety and efficacy over several decades since their introduction, earning the trust of thousands of medical professionals and millions of people around the world who rely on their sight-giving power."

What You Should Do Right Now

Understand that the data shared by Mamavation is meant to be raising questions, and not giving answers. There are many discrepancies in the published report that remain unexplained, and the authors intended their report to encourage readers to ask questions - not to make a decision by itself. They are calling for more research to be done, and doctors and patients agree and amplify that call. If you are one of the millions of Americans who enjoy contact lens wear, the overwhelming body of evidence supports that contact lenses are safe and provide improvement in vision and quality of life to many of us who prefer them as our primary vision correction, not to mention for the many Americans with corneal scarring, keratoconus, or corneal deformities who depend on contact lenses as their only way to see.

Research has shown that drinking water is by far the biggest risk of our exposure to PFAS chemicals, so there is one thing that you can do as a contact lens wearer to help. An estimated 15-20% of contact lens wearers in the US throw their contact lenses away in a sink or toilet.  Stop! These millions of contact lenses are contributing to microplastic waste in our environmental water supplies, and if there is a chance that the small amounts of hard molecule PFAS found in contact lens materials could somehow become water soluble and end up in our drinking water, that would be an additional problem! You can learn more about recycling your contact lenses for free with the Terracycle program here.