Does your average plastic lens get back-side SRC automatically or is it a separate, additional process?
Thanks!
Does your average plastic lens get back-side SRC automatically or is it a separate, additional process?
Thanks!
I never offer *ANY* non-AR lens as scratch protected, nor with any warranty for the same.
Keeps things simple.
Other than that, I'm not sure. I expect it may well depend on the particular supplier, and cost paid for said CR lens??
I agree with your policy, but I had a guy ask for "both sides coated" on his 1.67 lenses.
Now, he's getting AR so that answers that.
But I'm curious. If a lab has semi-finished blanks and surfaces the back side, is that the end of the process, unless otherwise requested?
Then it's an additional coating process?
Not to beat the dead horse of semantics, but we also don't offer *ANY* "coated" lenses. Those cheap pieces of flop are for onliners, and chumps. All of our lenses have varying degrees of scratch protection as it seems that's what your bloke had in mind. You did the right thing getting him into AR.
Getting into the lab side of things, I expect that yes, any lab worth their salt would utilize some form of final sealant on the finished "naked" backside - material dependent of course. Can you give your lab a quick call to ask about that specific area of their processing? I'm sure they can give you at least a rudimentary version of that process.
They still may not warrant it unless it's either a quality AR, or a scratch protection process like TD2 etc.
Any lens that gets a/r must be src on both sides or will you have coating failure very rapidly.. non a/r lenses of high index must have src. Cr is the only one where it is not essential. If the lab supplied a semi lens with coating on the front backside is optional on cr. Speak to your lab for their individual process.
(So, I'm getting the vibe that "coated lenses" is passe. There are just "non-glare" lenses, and they're "durable".)
Lensman you are saying:
1. If naked backside (that sounds obscene) on 1.67 (or other higher-index materials), it would scratch, so some process is prudent (AR/TD2, etc)
2. if naked backside on 1.49, you can get away with it.
Correct but not just 1.67 poly or 1.56 or anything except cr
I'm still trying to think in terms of what your pt was *really* asking for Doc. I'm guessing scratch resistance. You did the right thing with an AR lens (I'm guessing you also offer some form of lens warranty against defects and scratching for a set period of time?)
I just want to know.
We've done a TOOOONNNNN of naked poly over the years. We haven't, frankly, had issues with back surface scratching. I guess I've never thought about it for awhile.
I'm determined to get coating on everything as much as possible, though, and scratch resistance (oddly) is probably another good reason.
Doc, you’ve never had a “naked poly” lens, as lensman11 said, every, Every lens that’s surfaced automatically gets a src on both sides except for surfaced cr. All plastic lens materials are soft compared to cr, from the beginning with poly, they have all only come with both sides src coated. Most all semi-finish come with a factory src front. Labs usually only need to coat the backside.
Virtually all stock lenses, including cr come with factory src.
AR’s (good ones) require a stable lens surface src to adhere to.
All Rx’s you order, other than cr come with an src, even non-AR.
Reminds me back in the day when LC had associates “sell” src on poly. You simply can’t get those without an src, you even look at poly wrong and it scratches. You’d know after the 1st time you tried to clean a “naked poly”.
DRK
i am sure you never had poly that was uncoated on the back they would become unusable within days of purchase if you did.
What's your definition of "coating" in this context Doc? And are you simply trying to offer durability to your patients? If so, again I'll say you did the right thing with the AR lens. That way you're covering both durability and visibility. I, personally, also strongly discourage continuing to push the verbiage of "coatings" to your pts. It's not really accurate with most modern decent quality AR lenses particularly. And remember that 1000000% of the time, you say "coating" and the ONLY thing your pt hears is CHEAP, PEELING, SCRATCHING, FAILING lenses.Originally Posted by drk
They can get that online with any number of vendors for way less than your office. Why bother hanging out in the proverbial swamp with those lesser creatures?
I'm misunderstanding, then.
So most/all labs will do a backside SRC on every surfaced lens, then. (CR39 may or may not be an exception.) Do I have that right?
I honestly have been using "AR coating" terminology but I am going to change that immediately, after listening to how you all do it. So much better.
I'm merely conceptualizing the whole thing.
It seems that scratch resistance is not an added benefit of AR "coatings" then---just optical/cosmetic effects---because scratch resistance is a "given" on any lens. (CR39 may or may not be an exception.)
This guy said (believe it or not) "I want 1.67 lenses with Transitions. And I want scratch coating on BOTH sides, this time. I found out the hard way last time." To which I though to myself "hmm...do we ever NOT give people scratch resistance on both sides?"
I'm not exactly sure what you're saying here, but there ARE gradiations in the scratch-resistant properties of different AR lenses.
I'm Andrew Hamm and I approve this message.
Yes, I'm sure that's true.
What I was trying to say was, "in regards to scratch resistance, AR-coated lenses are not necessarily superior to non-AR-coated lenses, because non-AR-coated lenses have at least some SRC applied."
You are saying, I believe, "in regards to scratch resistance, SOME AR-coated lenses ARE superior to non-AR-coated lenses, because some AR-coated lenses have a superior-quality SRC applied."
I don't even push scratch coating as an a la carte option, because people end up thinking their lenses are supposed to be scratch proof. (When I worked at MyEyeDr we had to separately offer scratch coat for an additional fee and it felt like people saw it as nickel and diming. Any time a patient mentions scratch coating, I make sure to have the "there is no such thing as scratch proof lenses but all our lens options come with scratch resistance treatment included, and we offer a two year warranty for premium AR treated lenses." I also explain that proper care goes a long way to preventing scratches. I was under the impression that poly has to be scratch coated on both sides because it's too soft otherwise.
Krystle
Let me start by saying that the market where I work (Europe) is 99% characterized by RX lenses without preventive treatment on CX and therefore practically all of them are HC (SRC) and around 70% AR (on both sides).
In our laboratory I carry out scratch resistance tests daily on lenses produced by us or on competitors. The most significant test is called the Bayer test and is a test of variation in haze light after abrasion with grains of zirconium oxide and alumina oxide.
The higher the value, the better the scratch resistance
Poly 0.3
MR1.74 < 0.5
MR10 around 0.5
MR8 around 0.5
CR39 1 (reference value)
CR39 + HC (SRC) if not tintable 3-6
CR39 + HC (SRC) if tintable 2-4
MR8/MR10 + HC 3-5
If you put AR the Bayer value increases, if HC is of quality the increase is considerable, if HC is bad the increase is almost zero
for example:
CR39 + HC (SRC)if not tintable + AR 4-12
MR8/MR10 + HC 5-10
The absolute values of the measurement vary depending on the measurement methods but essentially the scale does not vary.
Consider that a BK7 lens obtains values around 10
I actually LOVE these sort of conversations! Allows you to forcefully and professionally take the lead to give the pt exactly what he's asking for - though he didn't know it! The perfect response from you:
"Excellent Mr. I-scratch-everything! We have the perfect lens for you, and it includes features that will perfectly meet your needs, including anti-glare properties that will make your vision as clear as in my exam lane, improve night vision, and even make your Transitions lenses more efficient and faster to change. Additionally, these lenses offer some of the best scratch resistance available today, since as you know, no lens is scratch "proof".
We love this lens because in addition to incredible visual characteristics, it also is backed with a 2 year scratch warranty. Should you have any issues with scratching whatsoever, simply let my office know, and we'll get a new pair of lenses ordered for you, completely free of charge! Your bases are all covered, and we're very happy to provide you with what we sincerely hope is the best pair of glasses you've ever worn! Will that be on a card, cash, or check today?"
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