How to clean your glasses properly, part 2: the lens manufacturer’s advice

Michael Restin

12/3/2026

Translation: Megan Cornish

From cotton to bamboo fibre, polo shirts to toilet paper – you use all manner of things to clean your glasses. We could write a whole series about it. Speaking of which, two experts from Carl Zeiss Vision have more tips for you.

I was shocked by how differently you all clean your glasses. My conversation with the expert from industry association «Optikschweiz» was flooded with opinions, routines, tips and in-depth questions. It was clear I needed to dig deeper.

I’m not the only one who wants to talk about this. Two experts from Carl Zeiss Vision also think there’s still a lot to be said on this topic. I set up an interview with them via Teams.

• Achim Zehender, Head of Sales Lens Care, is an expert in lens care and – among other things – wants to make the case for moist cleaning wipes.
• Stefan Kettler, Managing Director of Carl Zeiss Vision Swiss AG and Chairman of the Lenses Division of the Optics Swiss Suppliers Association (website in German), knows all things glasses and coatings.

Mr Zehender, do you generally agree with the cleaning tips given in my previous interview?
Achim Zehender: For home use, warm water and a non-greasy soap is certainly a good way to care for your glasses in the long term. However, I would stress that a clean cotton cloth should always be used for drying.

You’re referring to the «emergency solution» with the old t-shirt. I’m still stuck on the term «cotton». Is this natural fibre really better than special microfibre cloths?
Achim Zehender: Microfibre cloths are made of synthetic material. In other words, plastic, but in tiny, woven strands. There’s space between the fibres that can absorb dirt, but not moisture. A clean cotton cloth is so useful because it also absorbs moisture. You can use it to dry your glasses.

A microfibre cloth isn’t very effective for drying. Even if I carry one in every bag, it’s not much use in the rain.
Achim Zehender: Exactly. But most opticians are incredibly keen to give you a microfibre cloth. It’s not a bad alternative, as long as you store it properly. If you keep it in your trouser pocket, it’ll get dirty immediately. That’s why it makes sense to keep the microfibre cloth in your glasses case or a small pouch.

And then I can clean properly with it?
Achim Zehender: Clean, yes. For me, as a Swabian, that means managing to spread the dirt so you can see through it. But you can’t really clean with a dry microfibre cloth.

Besides cotton, people are using microfibre cloths and even old piqué polo shirts, bamboo fibres, tissues and toilet or kitchen roll – they argue that these materials are no longer as rough as they used to be. Everyone seems happy with their own method. Are scratches no longer such a big issue these days?
Stefan Kettler: When I started in this industry 20 years ago, we had plastic lenses which got scratched more easily. But damaged coatings are still one of the most common issues. This is due to consumer behaviour as well as lens quality.

How long should the coating last?
Stefan Kettler: The average Swiss person buys new glasses every four to five years. A modern coating lasts reasonably well for that long. But everyday life is varied, and things happen. Glasses are exposed to heat and cold, they get dropped or they aren’t stored properly – left in the car, for example. This scratches the coating. The same applies to an unsuitable cleaning wipe.

Scratching sounds like the opposite of gentle care. So why are so many people happy with their cleaning routines?
Stefan Kettler: It’s not just about the obvious scratches you can see in the light – you also create micro-lesions. This is on a nanoscale. For a coating to be anti-reflective, it needs to be half or a quarter the size of the amplitude of a light beam. Such a thin layer with a hard lacquer on top will eventually wear off.

You conducted tests and compared clothing with cleaning wipes. That’s really interesting, because so far everyone has only made their case based on personal experience. What were the results?
Achim Zehender: If we’re just looking at cleanliness, you find that lenses end up smeared if you use a dry garment. A damp wipe leaves them cleaner. That’s the one finding.

And the other?
Achim Zehender: In the long run, the garment causes visible damage to the coating. We’re talking about 800 wipe cycles, which is roughly equivalent to cleaning glasses 40 times. When you approach 1,600 cycles, the light refracts so much that you can’t really see through them properly anymore. This doesn’t happen with a moist lens cleaning wipe.

I assume you used a specially coated, high-quality lens for the tests?
Achim Zehender: Our hardest coating is called DuraVision, and it’s used on almost all of our lenses. In Europe, you can generally assume that lenses from an optician are coated well. The differences in quality only become apparent over time. But ultimately, it’s this coating and how it’s applied that make all the difference.

With my current glasses, I agreed to everything that was suggested to me. During the fitting, I was told that even eyelashes can damage the coating in the long run. Is that true?
Stefan Kettler: That’s possible. But if the glasses are so close to your face that your eyelashes can scratch them, something’s wrong anyway. Before fitting the lenses, you should know where they sit. Otherwise, I’d say that sweat is the bigger problem. Sweat is very corrosive if you let it dry on lenses. The more often you clean your glasses thoroughly, the better.

Some see ultrasonic cleaners as the ultimate way to get their glasses really clean and swear by them. Others say: «Careful, they’ll ruin the coating!» So, what’s the truth?
Stefan Kettler: It’s not a bad idea in principle, as long as you don’t wear glasses made of natural materials. The next question is what cleaning agent you use. Some people use spirits – that’s where we’d need to discuss it further. Otherwise, you can’t really do much damage.

Is there still a risk?
Stefan Kettler: I once had a major client where lenses suddenly exhibited very strange phenomena. They were polycarbonate lenses that didn’t react well to the ultrasonic coating combination and the additives we’d suggested for other lenses. So, in rare cases, problems can occur.

Which liquids should you generally avoid when cleaning glasses? Some people use high-proof alcohol, while others say that’s a terrible mistake and it’ll destroy the lens coating.
Achim Zehender: Opinions differ on this. Alcohol is the best at breaking down dirt and also dries very quickly. Plus, the glasses aren’t necessarily exposed to alcohol for a long time – which is more damaging to the frame materials than to the lenses and lens coatings.

The usefulness of moist cleaning wipes was also questioned in my first article. The criticism was that you just rub the dust around and wear down the coating like with sandpaper.
Achim Zehender: When used correctly, they can’t damage lenses or coatings. I once showed an optician at one of the largest optician trade fairs in Europe how to do it properly. When I’d finished, he looked at the glasses and said he’d been in the business for 32 years and hadn’t known how to clean glasses properly the whole time.

That’s reassuring… if he didn’t know, it’s likely that hardly anyone does. What was his aha moment?
Achim Zehender:

(Pulls a damp cleaning wipe out of a packet)

Our market research showed that 99.9 per cent of people start waving the cloth around straight away. But our packaging clearly states that you should wipe your glasses with the folded cloth first. Very gently and carefully at that.

(Takes off his glasses and starts cleaning)

If I do it this way, the worst of it is already gone, and I can also get right to the edge under the nose pad. That’s where most of the dirt collects. At home, I do it under running water. The damp cloth works on the same principle when I’m out and about.

And after that?
Achim Zehender: I unfold the cloth and turn it over. This way, I can use the clean, dust-free side to clean my lenses from the inside out, without any smearing or scratching. And that’s it – you can’t go wrong. It’s a microfine cellulose fibre cloth that can pick up even the finest dust particles.

Let's see if that convinces the sceptics.
Achim Zehender: We sell millions of these wipes every year. Over the last six years, I’ve only received one complaint. If you use sandpaper on your glasses, it won’t work. But if you do it right, nothing will go wrong.

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Then there are cleaning kits with a spray for when you’re on the go. What’s the magic ingredient in them? Water and soap? Glass cleaner? Or maybe strong alcohol?
Achim Zehender: It’s magic! (laughs) Of course, we’re not going to reveal the formula. But the thing is, the spray doesn’t contain any alcohol. It’s a liquid containing surfactants that cleans very gently. It’s the more sustainable option because you can use the spray and a microfibre cloth multiple times.

What can I do wrong?
Achim Zehender: Here too, it’s important to first carefully remove any loose dirt and dust. After that, I wouldn’t spray it directly onto the glasses – stick to a corner of the cloth. Clean the lenses thoroughly with that, and then with the other side. Otherwise, we’re back to the issue that microfibre doesn’t absorb liquid. But it works with very little moisture. This makes cleaning your glasses as quick and easy as with a moist lens cleaning wipe.

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Anti-fog wipes are a relatively recent innovation, which my first interviewee somewhat controversially dismissed as grease when we were discussing cleaning.
Stefan Kettler: Of course, you’re applying something to the lens. I’d agree with him there. And when you polish something, it has an optical effect: the lens can reflect a bit more light. Anti-fog wipes were in particular demand during the pandemic. I also use them for my swimming goggles, and they work quite well for three swims. But rinsing them with water after that removes the anti-fog coating.

So, it’s a question of weighing up the pros and cons. When does the benefit justify the effort?
Achim Zehender: When we go skiing or from outside into a warm room, our glasses fog up. There’s no simpler or more convenient way to solve the problem than with this anti-fog cloth. As an optician, you don’t always have to look for the effect in the light; sometimes you just have to say: close your eyes and get on with it, the customer will be happy.

Thanks for the chat! I can see things a bit clearer now, even without an anti-fog cloth. You’ve definitely convinced me to leave the t-shirt alone in the future.
(Both laugh)

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Michael Restin

Senior Editor

Michael.Restin@digitecgalaxus.ch

Simple writer and dad of two who likes to be on the move, wading through everyday family life. Juggling several balls, I'll occasionally drop one. It could be a ball, or a remark. Or both.

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