Polycarbonate vs. Trivex (NEW THREAD - edited by Moderator)

[Pete Hanlin]

They say you should try to learn something new every day...

Today, I had the distinct pleasure of touring the COLTS testing laboratory located here in Clearwater, Florida. Suffice it to say I have covered myself for a couple of weeks (i.e., I learned quite a few things during the tour).

Anyway, I thought I'd put one of the items up as a poll... enjoy!

[John R]

Well i hope you are going to post the result in a while...


.

[Pete Hanlin]

I will post the correct answer on Friday... I'm just curious to see what the perception is (perception being reality and all). As of right now, all four have one vote a piece... interesting.

[chip anderson]

I know that various ecconomic, manufactureing, political, and government agencies have axes to grind on optical materials but:
Does anyone have any actual statistics both US and international about how many eyes are lost or damaged due to :
1) Glass
2) Polycarbonate
3) Trivex
4) Other
Optical lens materials in everyday non-industrial non-sports life? Is it any? Is it a significant (of course one is significant) number?
Is the whole thing hype to sell more materials?

Is this just a sham like mandatory motorcycle helmets (head injuries are no more frequent in motorcycles than automobiles but helmets are not required in cars). But someone has sold a lot of helments.

Chip

[chip anderson]

Is ninety nine percent of the whole poly/trivex/whatever push just to protect ourselves from lawyers, or to protect the public?
Think of the poor ladder manufacturers, 80% of thier cost is safety labels and liability protection. They can't afford to make a safer ladder if they wanted to because the legal cost of produceing the same old ladder they have produced eats up all their cost an profit.

Are we allowing ourselves to fall into the same boat. Are we promoteing "safer materials" to drive up our bottom line and protect ourselves from a legal system gone mad?

Chip

[Joann Raytar]

Chip,

I think that liability issues may have a good deal to do with "Duty to Warn." I also think many people want thinner, lighter lenses. How do you create a lens that will be as thin as possible and safe at the same time.

We use both materials for drill mounts. I never had a problem drilling CR-39 if the process was done correctly and the customer wasn't too tough on their glasses. However, Polycarbonate and Trivex allow more people to get those 3-Piece mounts by being tougher to break.

[John R]

chip anderson said:
about how many eyes are lost or damaged due to :
1) Glass
2) Polycarbonate
3) Trivex
4) Other

I guess by others you mean frames, which must be the biggest cause of injures around the eyes no matter what material is used...

[Pete Hanlin]

I said I would post the info on Friday, and I am still trying to get more specific data on the impact resistance of Trivex. Unfortunately, I don't have some of the really cool instruments that R&D gets to use here in my office, or...
;)

I think the poll is rather interesting, however. Even after all the discussion, people are voting for option number one. Only three have voted for the correct answer (#2), and one of them was me, so...

Concerning Chip's question on eyes lost to various lens materials, I have always thought that anyone over the age of 18 should be able to choose whatever s/he wants for their lens material and design (including 1.8 index at 1.5mm if they so desire- given a thorough education concerning the material's tendancy to break). Of course, I am a proud card carrying member of the Republican Party's Conservative Branch (R.C.P.B.). Sorry Steve, that was too good of a description to pass up! Plus, its fitting- since I received my new voter's registration card just last week... just in time to vote for the President's younger brother!

Really though, what have we come to in this country? Perhaps we should keep people from buying Corvettes (they are capable of acheiving very unsafe speeds). Maybe we should require auto dealers to adhere to a "Duty to Warn" if their client doesn't purchase a Volvo (which is, after all, the safest car out there).

Perhaps John can look up some figures on just how many lenses are returned for shattering in the UK (since they allow the use of materials and designs the FDA has outlawed here in the states)?

Is ninety nine percent of the whole poly/trivex/whatever push just to protect ourselves from lawyers, or to protect the public?
I sure hope not! Polycarbonate stands as a terrific material even without the fact that it is the most impact resistant material currently used for ophthalmic lenses. Its light weight, high index, UV blocking properties, and ease of manufacture makes it a very attractive product.

Polycarbonate is the only ophthalmic product out there (other than Poly Methyl Methacrylate, which Chip is familiar with from his PMMA contact lens days) that is a thermoplastic resin. This means a manufacturer can take it in solid form, heat it up, press it into a shape, let it cool and BAM- you have a lens (whole process takes about five minutes, and you can chop up the material left over at the end of the process and sell it to other manufacturers who use lower grade polycarbonate for re-use).

All other materials are thermoset:
Allyl Diglycol Carbonate becomes CR-39... it must be activated (which makes the material start to heat up) and "sets" or "cures" into its cast shape. Once it has been locked into its final form, it will never melt again (it will ignite if sufficiently heated, but it will never be molded again), and anything left over at the end of the process is simply wasted. Also, it takes a considerable amount of time to properly cure the material if you want to end up with a quality product.

Methacrylate becomes your mid-index materials and is generally a UV curable product (you cast it and plop it under a UV lamp and it hardens). Once its set, that's it for this material too. The advantage of this material is that UV curing doesn't usually take as long as some other forms of curing.

Styrene and Thiourethane become your higher index materials and producing them involves toxic by-products that are basically unacceptable given the the EPA (Environmental Protection Agency) in this country. That is why most of your higher index materials come from abroad (mostly Japan). This is a cured product as well, and the curing can be very tricky.

Again, sorry for the length... however, the point is (I'm trying to find a way to win Steve over to Polycarbonate, and he is a proud card-carrying member of the Green Party), if you like efficiency and a relatively "green" product, Polycarbonate is for you! Given proper processing, poly is a financial, optical, manufacturing, environmental, and retail dream!!! Cue the poly theme song "Poly's great, poly's good, its used in lenses and in hoods" to the tune of the Barney song...
Thus concludes this installment of "Poly- A better way of life!"
;)

[Joann Raytar]

How impact resistant is Trivex? I can take a carpenter's hammer to polycarbonate and only dimple the surface; can you do that to Trivex?

[Chris Ryser]

Pete Hanlin,

Coming back to Poly on which you must be THE expert. When is anybody starting to apply a GOOD hardcoat to these lenses ?

I am talking purely in the interest of tinting these lenses.
So far I have been able tint the SOLA Oracle lenses to any dark tint we want. The hard coat, a polysiloxane which I can strip without problem, can take just about any punishment possible and tints superbly, but......................

these lenses have have been dip coated and retrieved to fast during the dipping process. Therefore the lower half on these lenses when retrieving has a considerably thicker coating and the lenses look like gradients. A good coating but with problems.

Any input is appreciated.

[Pete Hanlin]

Coming back to Poly on which you must be THE expert. When is anybody starting to apply a GOOD hardcoat to these lenses?
Actually, I would hate to be considered an expert on poly (I think there is a whole poly council or something who would be doubtless be able to provide much better info... does anyone know of a link to the poly council?).

As you no doubt know, Essilor approaches hardcoating poly from two angles... Our GLC (gotta learn how you guys put the copyright logo in on optiboard... one belongs after GLC and PDQ) coating is very scratch resistant- but not tintable to a significant degree.

Our PDQ (yep, it stands for "pretty dang quick") coating should provide pretty good tinting properties (according to our research, anyway).

Scratch coatings tend to be either/or when it comes to tintability and scratch resistance. The SOLA product does tint well, but I have been able to tint Essilor poly pretty dark as well. Of course, poly could be cast in a material that is already tinted to some degree (with a src that would allow darkening/coloration of the tint to taste), but there has to be enough demand for the product to make it feasible.

[Chris Ryser]

chip anderson said:
Is ninety nine percent of the whole poly/trivex/whatever push just to protect ourselves from lawyers, or to protect the public?
Think of the poor ladder manufacturers, 80% of thier cost is safety labels and liability protection. They can't afford to make a safer ladder if they wanted to because the legal cost of produceing the same old ladder they have produced eats up all their cost an profit.

Are we allowing ourselves to fall into the same boat. Are we promoteing "safer materials" to drive up our bottom line and protect ourselves from a legal system gone mad?

Chip

I still remember the good old days of glass lenses. People dropped them, they broke a lens or two. They went to their optician and got themselves a new lens replaced and never questioned the quality. Glass was glass and it could and would break, it would even scratch with time.

These days you get the lawyers involved when you scratch a lens that is so called scratch proof.

There is nothing in this world that undestructible and there should not be.

Maybe some day an inventor comes out with a lens that is undestructible and with age increases the power so you wont need any more than 1 pair of lenses for the rest of you life.

[Cindy Hamlin]

I have heard a lot about Trivex, but with my current position do not have much interaction with it.

I was reading an article in Lenses and Technology's October 2000 issue about "Dispensing Trivex Lenses" which I found quite informative. It was with the Vision Monday October 28, 2002 issue.

[Pete Hanlin]

Okay, our R&D department called back this afternoon with the information I requested. Essilor does not make a practice out of releasing specific results attained on other manufacturer's products (for legal reasons and because Essilor has a policy of selling lenses by describing benefits of our own product- not shortfalls of other company's products).

Now that the disclaimer is out of the way, what can be said (in general) about the impact resistance of Trivex is basically this- the impact resistant properties of Trivex are dependant on the manner in which the material is processed. Trivex can be processed in a way that leaves it more impact resistant than anything else other than poly- but it can also be processed in a manner that leaves it with the level of impact resistance we find in other ophthalmic materials that are not typically associated as having "high-impact resistance" properties. Likewise, depending on how it is processed, it can either meet or fail to meet the Z87 standards for high speed impact testing. There are some impact tests that Trivex may perform "better" than poly in (e.g., you can create a test where a weighted pointy object that pierces poly will bounce off a Trivex lens). Using the generally accepted impact resistance tests that the industry uses, however, polycarbonate- without question- is more impact resistant than Trivex.

I'm sure that, given time and broader usage within the market, a clearer picture of Trivex will be developed. Without a doubt, if you want to drill it, it has excellent tensile strength (its hard to make it split). My original (and remaining) point is that Trivex (contrary to the notion that had somehow impressed itself upon me and the vast majority of opticians I've spoken with) is NOT the highest impact resistant material on the market. How that affects your opinion of the material is up to you, of course.

[John R]

Pete Hanlin said:
impact resistant properties of Trivex are dependant on the manner in which the material is processed.

This has got to be true of any product for optical lenses....

What get me is everbody goes on about how strong the lens materials are but they can be as tough as steel but they are only held in a frame by a small bevel or even less a couple of screws...
I still think you are in more danger of injury by frames than any lens material on the market....

[RT]

Hmmm, Pete. Maybe a butterfly ballot is in order for this one <g>

Taking a giant step backward from the impact resistance issue, clearly both Trivex and Poly offer levels of impact resistance that are in a distinctly separate class from other materials. When both materials exceed the FDA requirements by several orders of magnitude, who cares whether one or the other shows miniscule superiority? I think we all agree that each material can take an arbitrarily hard hit that will leave the lens intact, and the frame embedded in the wearer's skull. Younger has a really cool film showing the "test" that you "could" create where the pointy thing penetrates poly slightly and bounces off Trilogy (Trivex). The point really, however, is that all other materials practically disintegrate. Difference in impact resistance, as you've suggested, can flip-flop based upon the engineering of the test.

Until, of course, the lenses are exposed to certain chemicals (acetone being the most common), at which point the lens performance deviates radically as we all know. As our Fearless Leader Steve has pointed out in other threads, material selection is really more than a single issue decision (oops--getting seriously close to nasty political tie-in, which would compromise my Independent status). Hey, we sell a ton of Poly and make good money on it. And we also sell a ton of Phoenix, which we position against ALL materials, not just Poly. Its a combination of mulitiple features, not just one, that makes the material what it is.

[sticklert]

I did answer you poll correctly (yeah!) and would like to point out or simply add to the statements about the impact testing on trivex. In any "real life situation" poly and trivex perform better than any lens material currently out. With that said there are ways to make poly or trivex fail depending on the test that is done on the lens. For example their is a device made with a spring loaded plunger that is pointed and about 10mm in diameter. You take this device and lift the spring loaded rod and release it into the lens which is sitting on a hard flat surface. This is a great test to show how polycarb flexes more than trivex because it can dent a quarter that is placed under the lens. However if you put a Trivex lens under it in most cases it would fail. (let me add that this was based on a 75mm blank size, and if the blank size is reduced to simulate the actual size of a normal edged lens say 50 mm the trivex lens passes) The bottom line is that regardless of which lens survived, if real human head was under the device then the person would be DEAD!. We all have to keep in mind that the tests done by independent testers are done to simulate "real life situations" and anyone can create a device that will make either polycarb or trivex testing fail.

We have to weight the cost, feature and benefits, and consumer expectations when dispensing eye-wear and I hope everyone will do what is in the best interest of their patients.

I am speaking from a perspective as an optician, but I do work for a Hoya Laboratory.

[Chris Ryser]

I am still trying to have an opinion on tinting trivex, anybody done it?

Tinting time? Color deviation from CR39 if tinted in in dye pot?

[Pete Hanlin]

The bottom line is that regardless of which lens survived, if real human head was under the device then the person would be DEAD!. We all have to keep in mind that the tests done by independent testers are done to simulate "real life situations" and anyone can create a device that will make either polycarb or trivex testing fail.
I think that sums things up pretty well!

I am still trying to have an opinion on tinting trivex, anybody done it?
The pair of Trivex (from Hoya, as I recall) that I ordered a few months back were to be made into sunglasses. Unfortunately, there was a defect in the application of the scratch coating (unrelated to the material, it was a processing error).

Anyway, as a result, I was able to notice how the material tinted with and without the scratch coating. From what I could tell, Trivex does tint (unlike poly, which just doesn't absorb tint), but not to the same degree as CR-39. I'm not sure how dark you could tint a naked Trivex lens... Why not order some Trivex lenses with and without coating and see what kind of results you get?

[Chris Ryser]

Pete Hanlin said:
The bottom line is that regardless of which lens survived, if real human head was under the device then the person would be DEAD!. We all have to keep in mind that the tests done by independent testers are done to simulate "real life situations" and anyone can create a device that will make either polycarb or trivex testing fail.
I think that sums things up pretty well!

I am still trying to have an opinion on tinting trivex, anybody done it?
The pair of Trivex (from Hoya, as I recall) that I ordered a few months back were to be made into sunglasses. Unfortunately, there was a defect in the application of the scratch coating (unrelated to the material, it was a processing error).

Anyway, as a result, I was able to notice how the material tinted with and without the scratch coating. From what I could tell, Trivex does tint (unlike poly, which just doesn't absorb tint), but not to the same degree as CR-39. I'm not sure how dark you could tint a naked Trivex lens... Why not order some Trivex lenses with and without coating and see what kind of results you get?

I CAN GUARANTEE ALL OF YOU...............that I can tint anything that is slightly tint able from Poly to Trivex to lenses of whatever material , to the darkest tint ever possible, right to the saturation point, in record time using the new tinting technology.

Chris Ryser

[jofelk]

I CAN GUARANTEE ALL OF YOU...............that I can tint anything that is slightly tint able from Poly to Trivex to lenses of whatever material , to the darkest tint ever possible, right to the saturation point, in record time using the new tinting technology.

Chris Ryser left his reply to tinting using the " NEW TINTING TECHNOLOGY" wide open.
Chris what is this new tinting technology you are selling? I have been looking for the technology that allows any tintable material to be tinted to any percentage and have the colors match consistently.
Can I finally get rid of my tinting units along with the mess and overhead expenses?

[John R]

jofelk said:
I have been looking for the technology that allows any tintable material to be tinted to any percentage and have the colors match consistently.
Can I finally get rid of my tinting units along with the mess and overhead expenses?

Enfatic NO.
Even Chris's MicroTintscan't tint to
ANY percentage. They will only go to saturation point..and the consitencity is all down to the coat the manufactures put on. But, Yes they can tint poly better than present tint tanks.

[Chris Ryser]

John R said:
Enfatic NO.
Even Chris's MicroTintscan't tint to
ANY percentage. They will only go to saturation point..and the consitencity is all down to the coat the manufactures put on. But, Yes they can tint poly better than present tint tanks.

I love this color setup, fancy computer technique,..............

But your are right John...............there is a limit...........but nothing to do with the way we'r tinting, the lens or the coating is the limit,
but we go darker faster than the smelly old tint tank, NO SMELL and the dyes last too long.

Chris Ryser

[Chris Ryser]

jofelk said:
Chris Ryser left his reply to tinting using the " NEW TINTING TECHNOLOGY" wide open.
Chris what is this new tinting technology you are selling? I have been looking for the technology that allows any tintable material to be tinted to any percentage and have the colors match consistently.
Can I finally get rid of my tinting units along with the mess and overhead expenses?

Jofelk,

I am not on the Optiboard to peddle my product. I am actually explaining a new idea that has evolved into a new tinting technique (US patents just issued Oct 15) which is the first time that there is a change from the original conventional over 30 year smelly, old dye pot system.

Yes you can really dump the dye pot if your willing to to learn how the new system works. Send me an e-mail and will give the details.

Chris Ryser

[chm2023]

chip anderson said:

Is this just a sham like mandatory motorcycle helmets (head injuries are no more frequent in motorcycles than automobiles but helmets are not required in cars). But someone has sold a lot of helments.

Chip

20% of all vehicle accident head injuries are to motorcycle riders, 12% to bicycle riders, so I don't see how the above can be true. (Source: Dept of Transportation/NHTSA website. )