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What's better: Contact lenses or glasses?

Kathleen Schuster
March 21, 2024

It seems like glasses would be the obvious eco-friendly choice, but not so fast! The answer is both fascinating and a bit mind boggling. Get ready for some eye-opening facts that could make you rethink your eyewear habits.


Interviewees featured in this episode: 

Dr. Charles Rolsky, Executive Director of the Shaw Institute 

Dr. Max Juraschek, Group Leader “Sustainable factory systems and learning factories” at TU Braunschweig 

Andrew Clark, Founder Net Zero Optics 

Listen and subscribe to Living Planet wherever you get your podcasts: https://pod.link/livingplanet    

Got a question for us? Or a suggestion for our new “What’s better?” segment? Email livingplanet@dw.com. And, if you like the show, leave us a rating and review on whichever podcast platform you use – and tell a friend!    


Episode transcript:

This is Living Planet, I’m Neil King.

We recently launched a new segment called “What’s better” to help answer your questions about how to make greener choices in your everyday lives.

In this episode, we’re going to hear from my Living Planet co-host Kathleen Schuster who’s been asking herself a question that’s quite literally right in front of our very eyes: What’s better for the environment: Contact lenses or glasses? 

Neil (on third beat): Kathleen.

Kathleen: Would you like to say hello to me or something (laughs)?

Neil: Kathleen, hello! We're here to talk about. What was it? Contact lenses versus glasses. What's better? Right?

Kathleen: Yeah, exactly. So, I've been looking into whether basically the environmental footprint of glasses is better than contact lenses or the other way around.

Kathleen: So, I want to ask you actually if you want to try to take a guess for somebody who's using contact lenses, how much trash do you think they generate in a year just by using contact lenses?

Neil: You mean in terms of tonnage, what you talking about? How much?

Kathleen: Yeah, just by, you know, throwing contact lenses away and all the packaging, like, how much trash do you think one person generates by doing that? 

Neil: Good God, I I have no idea. It would be a complete guess now. I mean, how often do you change them for starters?

Kathleen:  Well, yeah, so you can have dailies which you throw away every day, or you can have reusables which generally are like used about a month and then you get new ones. 

Neil: Right. And they all come in plastic packaging and stuff, so. 

Kathleen: Yeah, exactly. 

Neil: (Let’s out heavy sigh) Maybe 100 kilos? 

Kathleen: 100 kilos?! (laughs)

Neil: A year? I don’t know (laughs) Am I way off?

Kathleen: No, no. It's only it's about a kilo a year per person.

Neil: I told you I'd be way off. 

Kathleen: Yeah, way, way off. That's worse than I really thought. Thought I was bad at math. (Neil laughing throughout)

Neil: Give me multiple choice next time! Please!

Kathleen: So yeah, which do you think is better just by hearing it? 

Neil: Well, if you're just talking about the rubbish now, I mean, then glasses definitely would be better. But, but I mean, there's more to it, right? I mean, the production, the raw materials, I don't know, I would assume also making the lenses for glasses is quite energy intensive. 

Kathleen: Yeah, it's, it's actually what I thought was gonna be really easy to research was really, really complicated. 

Neil: Ok, so these What’s better segments as we’ve discovered, they always are complicated which is why we established this format in the first place, like in so that’s we established this format in the first place, right. So Kathleen, I’m dying to hear what you found out.

Kathleen: I called up several experts to find out how exactly the eyewear we use every day impacts the environment. And, whether one type is clearly more eco-friendly than the other.

One reason this is such an important question because by 2050 about half of the world’s population is going to need glasses. That’s according to a study from the University of New South Wales in Australia that’s been widely cited.

The first person I called up was Dr. Charles Rolsky. He’s the executive director of a non-profit in Maine called the Shaw Institute which studies how contaminants, like plastics, affect the environment and, ultimately, humans.

Back in 2018 when he was a PhD student, he was part of a team at Arizona State University that wanted to find out how Americans were throwing away their contact lenses. Where exactly were they ending up? 

Charles Rolsky: Contact lenses aren't very big. It's not a substantial amount of plastic, but if you're looking at how often they're used, you're looking at this increase in daily use lenses and the amount of people that use them.

Kathleen: They surveyed 400 people and found that up to 20% of the respondents were flushing them down the drain.

Charles: It's a substantial amount, and if you're if you're having that, go down the drain, it could lead to a substantial amount of plastic pollution in the environment.

Kathleen: Meaning it was possible that somewhere between 2 and 3 billion plastic contact lenses were ending up in the wastewater in the US alone.

He says after they figured out contact lenses were being flushed down the drain, they decided to follow their journey through the waste water to see if they stayed intact or got broken down.

Charles: We did a study in a way to our treatment plant to see how the lenses behaved when exposed to microbial attack. They withstood it really well, and we actually went through the final product of wastewater treatment, which is called biosolids. Basically, really nutrient rich fertilizer.

And we found a couple of fragments of contact lenses that we later confirmed to be the lenses later on. So it was a really telling study for us and that it survives the wastewater treatment process.

(reintroduce music)

Charles: They’re very porous. So, there's a chance that that they could be contaminated with things like diseases or other types of chemicals and they also became fragmented into microplastics.

Kathleen: There’s growing concern over microplastics across the world, which you might associate with larger plastic objects eike plastic bottles. But they can also be found in things like textiles and hygiene products.

These tiny particles travel easily through the environment, MUSIC OUT

especially in water systems and can contaminate the food chain eventually making their way back to humans.

Charles: So, it seems like a small change to just go from the drain to it, to solid waste, but it's very significant and meaningful.

Kathleen: Turns out, Dr Rolsky and other researchers could’ve only guessed how significant and meaningful. In 2023, two health websites – the Environmental News Daily and a site called Mamavation – commissioned a study on contact lenses in the US. And according to that study, all 18 different types of contacts they tested contained high levels of PFAS, otherwise known as forever chemicals. 


Kathleen: Right now, it’s still unclear whether contact lenses with PFAS are affecting people who wear them. But what is clear is that these toxic chemicals can contaminate soil and water and build up in animals. Again, potentially making their way back into our systems.

Ok, so at this point it seems like glasses must be the better choice.

Music out

But not so fast, we don’t have our answer just quite yet.

Yes, it’s true, once glasses are in the consumer’s hands, they don’t really generate any trash. Except maybe the occasional wipe.

But, one thing we can’t forget is that glasses are also a fashion accessory – and creating trash where we don’t see it.

Fast fashion causes


roughly 10% of global carbon emissions, according to figures from the UN, and glasses are adding to the number. Especially once the frames are out of style and end up in a landfill, just like clothing and other fast fashion items. 

One person who’s been researching this is a man named Dr. Max Juraschek. He’s   from the Technical University of Braunschweig in northern Germany where he leads a group researching sustainable factory systems.

Max Juraschek: Frames are a fashionable product. So this means basically two things,

It's not the standard frame everybody's using, so we have lots of different materials that are used. and then we have a big challenge of overproduction, because if you manufacture for instance frames centrally somewhere in the world and then you ship it all over the world, then they could distribute it into stores and then maybe half of them get actually thrown away

it's a fashionable product and maybe nobody's interested in this particular frame. So we have this kind of overproduction.

Kathleen: And let’s not forget – a lot of frames are plastic. So, a high number ending up in landfills means even more plastic waste floating around in the world. 

Dr. Juraschek and the team he was on wanted to find out if they could tackle this problem by manufacturing closer to the consumer. 

They conducted their case study in Syndey, Australia, and found that they could lower the environmental footprint of the frames by 25%. The key was to manufacture them locally from recycled materials that also came from the area – rather than importing the frames from China.

Part of this was small-scale production cut down on the overproduction. They also found customers had a greater connection to the product

That’s a big deal when you consider how many millions of people buy glasses.

Max: If you're looking at Western country like the United States, we're looking at well the consumption of nearly one frame per person per year. If we include sunglasses as well. So, it's actually kind of a huge market even for city like Sydney. This means for us that there's several million frames sold each year. If you look at the statistics.

It’s difficult to put an exact number on the environmental footprint of eyewear, though. That’s because a lot of companies don’t publish this data. That was something that surprised Max Jurascheck and his team.

Kathleen: And it’s something that’s also proven a challenge for a science communicator named Andrew Clark. In 2023, he helped found a consultancy team in the UK called Net Zero Optics.

The other co-founder is his father, who became a business coach after years of working as an optometrist and owner of several practices, including one that was a national flagship. Now they’re working together to help practices in the UK and beyond become more sustainable, which Andrew says is a tricky business.

Andrew: We think we're, you know, just a  fairly normal industry selling things that people like and you don't think more about the detail of them or what goes into them. But I'm sitting here with a lump of fossil fuels on my face because we are such a plastic heavy industry and the majority of it is derived from fossil fuels. […] we are in an industry that is very international, huge amounts of our manufacturing is done in China and over in the global East. And I'm sitting here in the UK at the end of those very, very long, convoluted supply chains. So every step in that journey is either refining a plastic product or moving a plastic product. And it very quickly adds up to a substantial carbon footprint.

Kathleen: He says he only knows of two eyewear companies that have released reports on their carbon footprints, so it’s difficult to boil it down to a number.

Especially considering how huge this global industry is.

Right now, it’s worth at least 150 billion US dollars and it’s is growing fast

Because by 2050 nearly half the world’s population is going to need glasses.

But if you’re trying to decide between glasses or contacts based on waste, let’s consider how much waste occurs during the manufacturing process.

Take the lenses, for example, which nowadays tend to be plastic as well.

Andrew: That starts its life as a lump of plastic, about the size of an ice hockey puck. It's huge and then is very carefully shaped and you know, huge amounts of it cut down to give only a few millimeters thick plastic on your face for the end user, so again the amount of waste is 80 to 90% of the original lump of plastic. It's massive.

Kathleen: Andrew says making the frames can generate a similarly high rate of waste, too.  

Ok, so what about sustainable frames? Take acetate, for example. It’s a really common plastic used for glasses, and it’s made from a mixture of plant-based materials and fossil fuels. But now there’s something called bio-acetate which is being touted as a sustainable material.

Andrew says this is very skillful greenwashing, though.

Andrew: Now that bio acetate, yeah, it might have a greater than average proportion of cotton or Castor bene in its physical makeup but it will still include a good percentage of by mass of directly fossil fuel derived material.

And that, to me, is a horrendous example of just

outright greenwashing because it's entirely wrong to say that a product that is 30% directly made of fossil fuels is sustainable. It cannot be. […00:03:04…] I would liken it to creating a burger. […] You couldn't possibly get away with saying oh, this is a vegan burger, 75% of it's a vegan.

Kathleen: So, plastic remains a big problem for all types of eyewear. On the one hand, it’s light and cheap. And crucially, it’s thanks to plastic that we have so many options when it comes to what is also a very important medical device.

But on the other hand, eyewear isn’t so easy to recycle.

The harsh reality is that only a very small fraction of plastic – less than 10% – actually ends up getting recycled. That’s because there are different types of plastics and contaminates that get thrown away – separating them is a complicated process.

A piece of good news, though. A handful of specialty recycling programs have popped up in the US and the UK over the past few years that handle both contact lenses and their packaging, and glasses, too. Andrew says in the UK drop off points at opticians’ practices have turned out to be popular. But it’s still early days.

Andrew: And because they are such a weird bundle of different types of material, largely plastic, but there's bits of metal in frames as well. In terms of the hinges and other bits, they can't. Immediately be recycled so those recycling centers separate materials into their component parts, and then you're left with plastic and plastic like products that you can't turn into anything else. And so those plastics are mixed with other difficult to recycle plastics, and they're basically. Shredded and heated and

compressed in a cocktail of. Are those strange plastics and turned into a very durable board that you can make construction sites and playgrounds and, you know, really cool stuff out of it? Gives this plastic a viable second life.

The only downside to it is that it's not a second life in the optical industry anymore, so we're a long way unfortunately from glasses becoming glasses, your spectacles becoming spectacles, lenses becoming lenses.

Kathleen: In theory this could be a good option for dealing with these specialty plastics. It could also help solve the question of what to do with the other materials, like frames made of metal, or the hinges. Plus, some people who wear glasses still opt for glass lenses.

And it seems like glass lens would be easier to recycle. But Andrew says that might be more complicated because of the protective coatings that get applied to lenses these days.

Kathleen: Okay, Neil. So now that you've heard all of that, were you surprised by any of it?
Speaker 2: Yes.

Kathleen: What exactly were you surprised by?

Neil: Well, first of all, I didn't realise that people were flushing their contact lenses down the toilet. I had no idea that people did that.

Kathleen: But you know, you know who's guilty of that?

Neil: You?

Kathleen: Not currently in my defence. Uh, have I lost my job now as an environmental reporter? Uh, no. But years ago, when I was still living in the States, when I think back, I know that I did that there, but I couldn't tell you why. I don't do it anymore, though. Does that help?

Neil: I think it does. I mean, I never I've never had contact lenses. I've always gone for glasses. And, uh, one of my takeaways, actually, I've been doing a pretty good job here because, you know, reusing the glasses are not, you know, changing the frame each time. I'm very good at that because I'm really bad at having my glasses adjusted. I should adjust them far more often and buy glasses more often, but I use usually have them much longer than I should. And then when I go, suddenly I can see again.

Kathleen: Funny. How that works. Um, but you know, I have to say, like, ever since I was researching this, I find myself staring at people's glasses and also thinking, which probably comes across as very weird, but I find myself thinking about how, you know, if you have like, different colours of plastic or different materials, like how much more difficult that is to recycle or to break down. But I was even thinking, like, I, I hate wearing my glasses and I have like 2 or 3 pairs at home. And I was trying to figure out like, where would I even take them? And this is also part of the issue of, yeah, how can you recycle them or what can you do with them? But um.

Neil: Yeah, I also I never really considered what materials actually go into my glasses. What are the frames made of? I never even considered that they may be, you know, different shades of grey, so to speak, and one might be more environmentally friendly than the other. Um, something I will consider next time around. But of course, as one of your interviewees said, there is a lot of greenwashing and it's there's no clear labelling yet, is there for glasses in the sense.

Kathleen: Yeah, but I think it's, um, there was one thing that didn't make it into the report that I thought was interesting, and that was on the topic of contact lenses. Um, when I was speaking with Andrew Clarke, he said there is a contact lens on the market that you only wear overnight, and it helps correct your vision. I'm not going to try to explain how it works because I seriously think, no, seriously, you you wear it overnight, apparently so you don't wear them during the day. You wear them overnight, but you can wear the same pair of contact lenses for up to a year.

Neil: I'm just looking to our technician here. I've. I've never heard of this. This strikes me as completely wacky. So you have them in at night when you actually not looking at anything, and then in the daytime you take him out.

Kathleen: Yeah. Apparently it does something with your cornea. And I don't dare say more than that because I'm not an expert on this topic. Uh, but, um, but yeah, so it is really interesting to consider how it's this thing that we, a lot of us can't live without. Um, but like these people that I spoke with, there's so little information out there that even they are, are really digging for it or having to do the research.

Neil:  Well, Kathleen, thank you very much for all that input. It was super informative. I really do appreciate it. And I learnt a lot about my own glasses and contact lenses, which I don't wear. Um, don't know whether that's going to change though, but um, yeah, I hope also our listeners took away a lot from this and we'll be right back after this short primer. This week's episode of Living Planet was produced by Kathleen Schuster. It was edited by me, Neil King, and our sound engineer was Jürgen Kuhn. If you have any environmental dilemmas that you'd like us to look at, please do send us a voice message or email to Living planet@dw.com. And if you're enjoying the new segments we've been including in the podcast recently, why not write a short review on Apple Podcasts? Or, if possible, leave a rating for us wherever you get your podcasts. That's it from the Living Planet team. For now, take it easy and take care.



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Living Planet

Looking to reconnect with nature? Want to make better decisions for the health of the planet? Every Friday, Living Planet brings you the stories, facts and debates on the key environmental issues of our time.