I am buying new reading glasses and the optician highly recommends buying lenses with so called lotus effect coating. This makes them much easier to clean, or so he claims, though it is not for free: around additional 100 Euro/Dollar for both lenses. I just wonder: is there really such a thing as a lotus effect coating for optical glasses, or is it just a fancy name for a different kind of coating? With different kind of coating I mean one that is surely effective for preventing dirt adhering to the lens, but that is not based on the lotus effect but another mechanism, whatever that is. I am lead to believe that without any quotable basis apart from my skepticism for marketing hype because the lotus effect is based, if you allow the simplified explanation, on a microscopic coating of a surface with tiny bumps that make it difficult for water to stick to it. The bumps are minuscule and prevent water, which has a high superficial tension, from sticking to the lens, so it forms a round drop that, well, drops off easily. But how can this be achieved without ruining the optical properties of the lens? Would those bumps not scatter the light, making it foggy? Lenses are polished for a reason after all. Would the microscopic bumps not wear off with cleaning?
I am not denying that there is a coating that keeps the lenses cleaner just like the optician claims, I just wonder whether the name is technically correct. Does anybody know? A cursory search of the web gives results about how great this coating is, but not about how it is really made. Thanks to the experts in advance!
If anybody wants to discuss optical glasses in general and/or this thread is moved to miscellaneous and personal stuff I must share I do not object.
Do you have any extra details about the manufacturer of the coating? Even a trademarked term would be useful.
Hydrophobic (and super-hydrophobic, and ultra-hydrophobic) coatings are a thing, and don’t necessarily interfere with the optics. But I agree about the wear risk. The coatings I’ve seen have poor durability.
It’s possible they’ve come up with a more durable system. Maybe they etch the glass itself. But I’d definitely look into the company making the coating.
I found a few articles referencing “lotus effect” for glasses (see below). Seems a super-hydrophobic coating that acts like lotus flower leaves.
I make NO claims to the quality or value of this. Just found some citations. It does seem the one cite suggests that opticians charge a lot for this but, of course, they are selling their own thing so…grain of salt.
I will say, for me personally, water and dirt is not the problem on my glasses. Oil from fingers or my face or sometimes I have no idea where seems the main culprit and difficult to clean. I do not know if hydrophobic coatings help with that (since, obviously, oil is not water).
The second type of self-cleaning is a type that is applied with a hydrophobic coating also known as having the “lotus effect” which refers to the very high water repellence exhibited by the leaves of the lotus flower. Dirt particles are picked up by water droplets due to a complex micro- and nanoscopic architecture of the surface which enables minimization of adhesion. - SOURCE
Nanotol nano coating replaces the expensive lotus effect coating by the optician. Finally, spectacle lenses can be refined in such a way that they repel dirt and dust. Cleaning is therefore very easy and gentle. The invisible protective layer also counteracts scratches caused by conventional cleaning. - SOURCE
SOURCE 2 (more info on their coating)
Similar to the well-known lotus effect, the droplets all rolled off the superhydrophobic glass surface, as shown on the left side of the glasses in Figure 4a and Figures S2 and S3 in supplementary informa- tion. - SOURCE
I’ve been wearing glasses 16 hours a day (or more) for 50 years now. I’m not sure why cleaning them is so difficult for some people.
I do know that some of the coatings promoted are very fragile and easily messed up/worn away. Are these easier to clean but require special treatment for cleaning?
I forego coatings for the most part. Just how I roll, you may have a different opinion.
No, I don’t have a trademark ready, but I will ask the optician next time I speak to him.
I have worn contact lenses more time than glasses, but I agree with you, I still wear glasses every day before and after putting the lenses in and out and it is not hard to clean them. But what intrigues me is whether this lotus effect sales pitch is marketing bullshit or really the lotus effect.
The lotus effect in itself, btw, is quite cool. I just doubt it can be used for spectacles.
Did you see my links above? The last one literally shows it working.
Whether the coating is fragile and not worth it I do not know.
Yes, I read your last link now: OK, so the name is not a mere marketing ploy but real bumps on the glass surface. Not bad, I will check how it works in real life. Thanks!
I bought the glasses with the coating and must say that it works like a charm. They are easier to clean and stay clean longer. I was skeptical, I am convinced. The glasses are completely transparent, no scattering of light at all, and the coating does not seem to rub off (after only two months of cleaning). Thanks again for your links, @Whack-a-Mole and FYI the coating works great against grease too. It is very easy to swipe off leaving no traces. The 100 extra Euro were well spent.
I’m curious if they’re better in rain than regular lenses. Does the rain run off more easily?
I have not tried them out in the rain: they are reading glasses, I use them in dry closed rooms. Sorry! But: probably yes.
Wear them in the shower and report back! 
That is a simple test, I will. Tomorrow morning, promised.
Bring a book with you.
Or an ebook reader.
They stay fog free (of course it is warm now, perhaps not so good in winter when you come in from the cold into a warm room) and relatively dry on the shower. The water pears off like from a duck’s back when you shake your head a little, some smaller droplets remain. Not perfect, but good.
ETA: Instead of an ebook reader I took my phone with the amazon reader app: IP68 works as advertised too. Still, it is silly to read in the shower. That is what bath tubes are for.
Thanks for the report!
I’m wondering if this coating can be applied to already-been-used lenses. As in the ones I currently wear. It’d be nice to have lenses that the water slides off of when I’m out bicycling in wet weather.
That is a question for your optician, but I guess he will try to sell you a new frame with the new glasses. The wind while cycling, on the other hand, will probably help to sweep the drops away, it was like that on the motorcycle’s helmet years ago, when the coatings were more primitive, I guess that has improved.
They didn’t when I had the lenses made earlier this year for these frames. And I’m not buying new lenses; these were pricey enough. I’ll give them a call.
Go to McD and buy a Big Mac … Will Coke be your beverage? … Medium or large fries?
→ those poor min.wage.worker had training to “upsell” you … to increase the ticket avg. for this particular venue.
the same is happening here … the guy is trying to tack on as much moolah as possible as he can extract from you … (did he offer insurance?) … I loathe when healthcare-“professionals” try to leverage the trust you deposit in them to milk you for what its worth.
Dentists are normally the worst offenders for trying to bump the bill.