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Science Forum Index » Medicine - Vision Forum » AR coatings are not durable long-term
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| SQ |
 Posted: Wed Apr 16, 2008 5:11 am |
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Guest
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I got an AR coating for the first time in my life, on high-index
lenses.
Before these, I had regular non-coated glasses that I used to clean
with TP or Kleenex -
the lenses held up well, no scratches. Always followed the same
procedure: Wash with mild
soap solution, clean while wet, wipe until dry. No problems.
Tried cleaning these new AR coated lenses with Kleenex and what a
mess. Caused several
deep scratches and a myriad smaller ones. Never had that issue with
non-coated lenses
for 10 years, not one scratch.
So I switched to a microfiber cloth and cleaned very carefully, using
soap-based solutions
without alcohol, cleaning only when wet. The scratches stopped. But
about 6 months later,
the coating started coming off in chunks, started to see crazing,
blurry spots while
looking through the glasses. It's a disaster.
In a nutshell, with AR, I had issues with:
1) Scratches
2) Coating coming off
3) Staining
The coating I got is junk, plain and simple. Not sure what the brand
is. I took it back to the
store and they promised to replace with lenses with another coating.
I hope it's a premium coating like Crizal and more durable.
Basically my conclusion is that not all AR coatings are created equal,
and that they are all
high-maintenance. My next pair of eyeglasses will not have them. I
never had issues with
glare or anything like that, they fix a problem that doesn't exist and
reduce long-term
durability.
AR coatings are vulnerable to a multidude of things that non-coated
eyeglasses are not
sensitive to:
Having highly acidic perspiration
Cleaning with Kleenex
Chlorine from swimming pools, salt in sea water - if you must wear
your glasses
while swimming
Excessive heat, i.e. leaving them on the dashboard of your car
Hairspray
Acetone
Windex, or any cleaner containg ammonia
My last pair of eyeglasses without a coating lasted for 10 years
without a scratch
and was highly durable.
IMO it's just a way to extract more cash from the consumer by selling
these junk
coatings, saying that you "need" them, like car dealers that push
overpriced,
unnecessary options. I asked my optician if I could get a pair without
AR coatings and
was told "No", that explains everything. |
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| toddster63 |
| Posted: Wed Apr 16, 2008 6:09 am |
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Invest in some lint-free microfiber polishing cloths. Most places just
give them away these days, and if not they are cheap. They clean the
lenses wonderfully, with nary a scratch. You can hand wash them every
so often, and they dry very fast.
I have been using these microfiber cloths on my sunglasses and
eyeglasses, and they truly make a difference--no more TP, or Kleenex
again! That just causes too many scratches with coatings and
sunglasses...!
And you are right--a lot of the AR coating are rip-offs and priced way
too high for inferior quality. I think the prices for Crizal are a
bit of a joke, but it does seem the most durable of the lot, so what
are you going to do...?! |
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| Salmon Egg |
| Posted: Wed Apr 16, 2008 5:17 pm |
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I have complained for a long time that the current style for using
plastic lenses and all the consequent sequelae. Glass lenses just will
have better optical properties and better scratch resistance than
plastic.
Moreover, glass allows the deposition of coatings that require
temperature temperatures so high that plastics cannot be used. High
temperature deposition can lead to coatings s durable that can be
removed only with great difficulty. It still frequires cleanliness and
careful preparation of the lenses.
Unfortunately, it is getting very difficult to get lenses and
practically impossible to obtain hot coatings. Hot coatings are used for
much optical equipment but not for spectacles. I just had to settle for
plastic lenses and compatible coatings. Both were not cheap.
To give you an idea of the durability of good coatings, there are
military specifications that call for testings coatings. This include
rubbing the coating with a soft pencil eraser to insure that the coating
will not rub off. Another test applies Scotch Tape to the coating to
make sure that it will not lift off when the tape is pulled off.
Bill |
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| SQ |
| Posted: Thu Apr 17, 2008 5:02 am |
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toddster63,
I used a microfiber cloth for the last 6 months and it has slowed
down, but not prevented disastrous peeling, crazing and staining. I
wash the microfiber cloth weekly, use it only when they are wet, etc.
and it hasn't helped all that much due to the fragile nature of the
coating. This AR coating is in such a poor shape that it should be
removed totally, if I find a product that can do that. I will try to
find out the name of it so that others can avoid it.
My optician promised to exchange it for free under warranty, so I am
not really loosing anything other than some time and frustration. Plus
I got some experience and education out of it.
Salmon Egg,
Interesting points you make. I noticed that hydrophobic coatings on
high-end optics are so durable as to next to impossible to remove or
dissolve. They are also very scratch resistant. I wonder if they are
"hot coatings". I think my next pair will be glass + hot coatings if
I can find someone to do it. Or else regular plastic without
coatings. But not this disaster. |
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| Salmon Egg |
| Posted: Thu Apr 17, 2008 9:48 pm |
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In article
<b00e3e11-41a5-4d1b-bd93-7237ae37c044@k13g2000hse.googlegroups.com>,
SQ <onestatusquo@yahoo.com> wrote:
Quote: Interesting points you make. I noticed that hydrophobic coatings on
high-end optics are so durable as to next to impossible to remove or
dissolve. They are also very scratch resistant. I wonder if they are
"hot coatings". I think my next pair will be glass + hot coatings if
I can find someone to do it. Or else regular plastic without
coatings. But not this disaster.
What material is used for your lenses? If you can find someone who hot
deposits, please let me know about it.
Bill |
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| Robert Martellaro |
| Posted: Fri Apr 18, 2008 5:24 pm |
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Guest
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On Wed, 16 Apr 2008 08:11:25 -0700 (PDT), SQ <onestatusquo@yahoo.com> wrote:
Quote: I got an AR coating for the first time in my life, on high-index
lenses.
Before these, I had regular non-coated glasses that I used to clean
with TP or Kleenex -
the lenses held up well, no scratches. Always followed the same
procedure: Wash with mild
soap solution, clean while wet, wipe until dry. No problems.
Tried cleaning these new AR coated lenses with Kleenex and what a
mess. Caused several
deep scratches and a myriad smaller ones. Never had that issue with
non-coated lenses
for 10 years, not one scratch.
Kleenex did not cause the scratches.
Quote: So I switched to a microfiber cloth and cleaned very carefully, using
soap-based solutions
without alcohol, cleaning only when wet. The scratches stopped. But
about 6 months later,
the coating started coming off in chunks, started to see crazing,
blurry spots while
looking through the glasses. It's a disaster.
The coating process was done improperly, and/or it was a cheap coating.
Quote: In a nutshell, with AR, I had issues with:
1) Scratches
2) Coating coming off
3) Staining
The coating I got is junk, plain and simple. Not sure what the brand
is. I took it back to the
store and they promised to replace with lenses with another coating.
I hope it's a premium coating like Crizal and more durable.
I've only seen two or three coatings fail in the eight years or so that I've
used Essilor's Crizal. A consistently high quality product.
Quote: Basically my conclusion is that not all AR coatings are created equal,
You got that one right!
Quote: and that they are all
high-maintenance.
Clean with soap and water, dry with a clean cloth, put them in the case when not
worn. AR or not.
Quote: My next pair of eyeglasses will not have them. I
never had issues with
glare or anything like that, they fix a problem that doesn't exist
Surface and internal reflections, starbursting, light loss, and veiling glare
are real issues with optical lenses. If they don't bother you then skip the AR
on your next pair. However, your glasses may have been flawed from the get go so
it might be hard for you to judge the benefits or lack thereof.
Quote: and reduce long-term durability.
Nothing lasts forever. Think of items that you wear every day that last ten
years.
Quote: AR coatings are vulnerable to a multidude of things that non-coated
eyeglasses are not
sensitive to:
Having highly acidic perspiration
Eats up frame finishes, metal and plastic, and sometimes the hard coatings on
the lens. Glass seems to be immune.
Quote: Cleaning with Kleenex
is ok if there's no lotion added. I use Kimwipes at work. I wouldn't use them on
a coated lens that I was keeping for thirty years, like a photo or astronomical
lens. At home and for my clients I use/recommend Luminex's microfiber, made by
Toray Industries in Japan.
Quote: Chlorine from swimming pools, salt in sea water - if you must wear
your glasses while swimming
I've been in some pools where it felt like the chlorine was taking my skin off.
Quote: Excessive heat, i.e. leaving them on the dashboard of your car
I wouldn't put my camera there on a hundred degree day.
You'll need a solvent like denatured alcohol to get it off the frame and lenses.
Don't use this anywhere near eyeglasses.
Quote: Windex, or any cleaner containg ammonia
Ditto.
Quote: My last pair of eyeglasses without a coating lasted for 10 years
without a scratch
and was highly durable.
IMO it's just a way to extract more cash from the consumer by selling
these junk
coatings, saying that you "need" them, like car dealers that push
overpriced,
If you pay for junk then it was probably overpriced. How much did you pay for
this junk coating?
Quote: unnecessary options.
Unnecessary for you, essential for me, and from desirable to essential for about
80% of my clients.
Quote: I asked my optician if I could get a pair without
AR coatings and
was told "No", that explains everything.
I've heard that there's a chain of optical stores that's selling coated lenses
only- might be Sears (Cole National, now Luxottica). I don't recommend it for
everyone; some people are too lazy to clean their glasses everyday, some types
of Rxs, lens materials, and designs may not benefit as much from coated optics
as others, and might be money that could be better spent elsewhere in their
ophthalmic budget. Try this next time- tell the optician that you clean your
glasses twice a week, and then ask if you should have an AR coating. If they say
yes, then grab your wallet and run.
Robert Martellaro
~~~~~~~~~~~~~~~~~~
Optician/Owner
Roberts Optical
Wauwatosa Wi.
~~~~~~~~~~~~~~~~~~
"Science is a way of trying not to fool yourself."
- Richard Feynman |
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| SQ |
| Posted: Fri Apr 18, 2008 9:05 pm |
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Guest
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Robert Martellaro,
Thanks for your interesting comments.
High quality glass should never be cleaned with any paper products,
including Kleenex.I had a pair of eyeglasses that was rather immune to
kleenex (TP is an even cheaper and viable alternative) but these days,
I don't risk it and use Microfiber cloth.
Quote: The coating process was done improperly, and/or it was a cheap coating.
I think so too. I didn't even understand they put a coating on it
until after I got the glasses. I didn't even know what a coating was.
So I got stuck with some cheap coating that came off within months of
use.
Two things just came up:
First, I just got a replacement lenses per warranty, the store was
nice enough to take care of that (on a pair of $500-600 eyeglasses,
you expect nothing less). I inquired what they were, and was told
they are Essilor. (don't know specific model) I asked if they were
AR coatings, and they said no, it's just a scratch-proof coating (and
seems to work BTW, much easier to clean). And it's definitely
hydrophobic. It seems to be a quality coating, but it's not AR.
The other interesting thing I was told was that the previous coating
that got damaged was *not* an AR coating. I have a hard time
understanding this, as it was green when looked at the front of the
lense, a sign of an AR coating, and if not AR, then what was it?
Certainly not scratch-proof as it miserably failed in that regard.
Another thing that I find peculiar is that I *think* these old not-so-
durable coatings gave me a higher contrast than what they replaced it
with. I asked them, did not get very many meaningful answers and just
left it at that.
Now question for you: How durable is Essilor's Crizal long-term? I
don't want to replace my lenses every 2-3 years.
I suspect that these lenses I just got are Essilor's AirWare as they
feel much lighter than the older lenses. They also seem to have more
chromatic abberations and do not have the same high contrast than the
older lenses with the slightly heavier lenses. |
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