Polycarbonate
I have a ? on polycarbonate lenses. I personally, do not like them because they seem to scratch more on the backside of the lenses more than any other lens, however, since it is the safest lens available, I am supposed to recommend to everyone including children who are rough on glasses. I agree the very first important factor is saftey which would definatley be poly, but what about the scratches? Does anyone know how trivex compares to poly and should I be recommending that?
Trivex seems to scratch the same, is thicker, and has better optics.
Please also note that with kids poly is not always nessecary for safety. Many kids are high plus +6 etc. In this case a 1.60 surfaced lens wouls stop a diesel locomotive, and is safe.
With kids scratches are just a way of life. Optically I prefer trivex or high index.
What type of coating do you have on them. If you have a coating like UT or TD2, or a good AR coating like Crizal or Zeiss then it should be pretty scratch resistant.Originally Posted by April_01
I have a ? on polycarbonate lenses. I personally, do not like them because they seem to scratch more on the backside of the lenses more than any other lens, however, since it is the safest lens available, I am supposed to recommend to everyone including children who are rough on glasses. I agree the very first important factor is saftey which would definatley be poly, but what about the scratches? Does anyone know how trivex compares to poly and should I be recommending that?
For-Life,
I don't think a scratch coat protects for 4 year old attack!
A super hard-coat like the ones I mentioned would cut down on it though.
I am not sure what kind of scratch coat is on the basic lens of the poly, but I will look into it. However, I am kind of leary about putting an anti glare coating on a kids lens because of the fact they are usually so rough on the lenses and parents don't want to pay extra for something their child won't take care of and might scratch.
[QUOTE=April_01]
However, I am kind of leary about putting an anti glare coating on a kids lens because of the fact they are usually so rough on the lenses and parents don't want to pay extra for something their child won't take care of and might scratch.
[/QUOTE]
Selling AR coatings on kids Rx's is plain and pure rippoff of parents wallet by the optical trade.
Kids have forever mistreated their glasses and should be given just good strong frames and a pair of resistant frames at a basic price.
I totally agree about the anti glare coating on kids lenses, but my boss came up to me the other day and asked me how places like walmart can get almost all kids and adults in a/r lenses. He based this opinion on the fact that almost every pt that has come into our office (after having gone to walmart) had antiglare coating on their lenses, including kids. I can not recall one pt in our office who elected to go with anti-glare for their kids. What's wrong with this picture? Is walmart more conviencing or is it price? Or both? Either way the kids usually have scratches on the lenses due to the coating and their parents either elect not to go with it or didn't know what the a/r was. When told that their child had it, they thought it was the just a bad scratch coat! I don't feel so bad after all! :)
This is from a thread last week questioning whether or not to offer AR, among other things, to kids:
AR on kid's lenses??? He** YES! It has to at least be a consideration. New coats, such as HOYA's Super HiVision, Essilor's Crizal Alize, and Sola's Teflon (to name a few) offer an order of magnitude better abrasion resistance than simple scratch coating. Scratched and dirty lenses that Junior can't see out of? That's precisely the reason to offer the newest offerings in AR--far harder to scratch, far easier to keep clean, so the lens can do its job. And if a nice looking AR helps the child with the stigma of wearing glasses, so that he/she actually wears them...
Funny how the wisdom here is to not offer cheap frames, but then offer cheap lenses (you know--the part that actually corrects the child's vision). You'd offer AR coats to relieve eye strain to the teacher working under schoolroom lighting, but wouldn't offer it to a kid trying to learn under the same conditions? How's that fit with the "No Child Left Behind" program?
You at least have to present the AR, and let the parent make an informed decision.
RT
It is my understanding that the WalMarts around here offer a Poly with A/R as standard with their children's package. I have had many folks come in with a walmart a/r that was ruined after just a few months. I have been told they use a Zeiss coating.
I agree that an A/R (a quality A/R with a good warrantee) should be offered to children. Some of these kids are going to have brand new cars at 16, expensive summer camps every year, and all the latest and greatest brand name clothes. Why should we refrain from giving them all the options and prices? Let the parents decide. An a/r has all the benefits for children as for adults (with the exception of improved night driving), so why not offer it?
As for scratch resistance, I would take a shv, alize, or other similar lens over a stock poly of sr CR39 any day of the week for longevity.
AA
What is UT amd DT2 coatings
Sorry, Chris, but you're wrong about the abrasion resistance of the newer coatings. Here's some sample Bayer Abasion Scale results for various coats:
HOYA Super HiVision 10.9
SOLA Teflon 6
Zeiss Carat 5
Crizal 3.6
Older AR coats 2.2
I don't have figures on Crizal Alize, but I believe it to be similar to SOLA Teflon at about 6.
As you can see, the newer coatings do perform better, as measured by the most commonly used metric for abrasion resistance. And that's precisely my point--opinions about AR coating durability formed several years ago need to be reviewed in the context of newer product offerings. The fact of the matter is that a lens with Super HiVision offers an order of magnitude better abrasion resistance than lenses with a standard scratch coat.
RT
RT
Are you telling me that there is some super new hard coat on top of the AR coating which gives an AR coating better scratch resistance ??????
The thing is that most AR coatings use a better quality scratch coating like UT or TD2, so that is why there are more scratch resistant that the regular plastic SRC lens. I don't think there is a difference between UT and UTMC, or TD2 and Crizal or Alize. The only difference might be that the AR is hydrophobic, Anti-Static, and/or Oliphobic, so it repels stuff like dirt that can be wiped into the lens; however, I do not know if there is any fact to that.
UT(Ultra-Tough) is Sola's superior scratch resistant coating. A UT coated lens, unlike the ready made hardcoated lenses with one side or both side hardcoat, is vaccuum sealed. It offers a superior scratch resistant coating. The UT is the foundation of UTMC (Ultra-Tough Multi-Coat) Sola's AR coating (before the new teflon). Apparantly it has the same scratch resistances at UTMC.
It is the same thing with Essilor's TD2. It has the same scratch resistances as Crizal and D Alize, but with the glare. I know Nikon also has their HC coating, and some other companies have their super-hardcoat.
The only problem with these hardcoats is that like AR you cannot tint them. You can tint the lens before you apply the coating, but not after. However, for the argument of if we should or shouldn't provide AR for kids, we can still give them a superior hardcoat without giving them AR.
I think part of the AR coat for kids equasion is the lab. My lab offers a lifetime warranty against scratching if Crizal, Alize, UTMC, or the like is chosen. The child can come back once a month for two years and my lab will replace it under warranty at no charge. This is certainly no rip off, and in fact, like purchasing a warranty for the parents. It costs more up front, but benefits the child and the parent in the long run. If your lab doesn't offer a similar warranty, you may want to shop labs. I pay a little more, but easily make up for it with two year polycarb scratch warranties and AR coat warranties.
In the imortal words of Socrates, 'I drank what?'. -Chris Knight (from the movie Real Genius)
You are now jumping into my ballpark.
Polycarbonate lenses can be scratched with a Kleenex if not hard-coated.
In order to make the lenses tintable manufacturers or you wholesale lab apply a backside coating.
The more tintable the backside coating the softer it gets. Tintable backside coatings on poly are usually softer than an uncoated surface of a CR39 lens.
That is the real reason why the backside surface of poly's and other non tintable lens materials scartch easily. Only if non tintable coatings are used you will NOT have this problem.
All I can add is that we sell a lot of poly and AR (sometimes even on the same Rx) but I don't wear it, much happier with Trivex.
MRBA
I dispensed a progressive to a first time wearer Monday. She is 93 years old and didn't want to see lines on her new drill mounts that she put Crizal on. Her exact words were "I'm really tickled by these no-seeum bifocals!"
When's the last time you got to tickle a 93 year old lady ?
If you do not at least offer AR to the parents of the children you are dispensing to, you are not doing your job. Just because a child "may" scratch a lens, that does not outweigh the benefits an AR coating. Many kids in school are dependant on computers, go to classes with fluorescent lighting, and rely on excellent vision throughout the day, why not offer AR. If you think that $75 dollars or a $100 is a rip-off or a waste of money for an AR coating on kids glasses, then fine don't make those glasses for your kids, but at the very least offer the product to other parents, don't make their decisions for them.
When are you guy's going to remember the teachings on this board by specialist's as from Essilor and others ?
New coats, such as HOYA's Super HiVision, Essilor's Crizal Alize, and Sola's Teflon (to name a few) offer an order of magnitude better abrasion resistance than simple scratch coating. Scratched and dirty lenses that Junior can't see out of? That's precisely the reason to offer the newest offerings ........................
The hard coats mentioned on a AR coated lens are NOT to protect against scratching. These hard coats have been applied on the lens surface to give a proper adherance to the AR coating which would not adhere properly on plastic lenses. Therefore there is NO hard coat on top of the AR coating itself, and above statement is false.
Some products now offer a slick coat that seals the surface and makes it easier to clean. There are also slick coats available that you can easily apply yourself in your office on any AR coated lens for little money. You can lool it up at at http://optochemicals.com
So, do you think plastic is better for people that complain about the lenses scratching too easily? I thought poly was stronger, but wonder about the scratching.
Thanks
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
Bookmarks