# Optical Forums > General Optics and Eyecare Discussion Forum >  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... :Rolleyes:  


.

----------


## 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. )

----------


## chip anderson

Wish I could find an E. Mail I once received on how we survived the 50's (the last time America was happy) for you.  Then you might begin to understand.  But I doubt it as you probably grew up in a world that believes it needs government protection.

Chip

----------


## chm2023

Actually I grew up in the fifties.  I completely agree it was a wonderful time.  Some of us even learned math!!!

----------


## Shutterbug

I just have to add my $.02.  I tried poly lenses for myself (not aspheric though) and could not tolerate the "tunnel vision" I experienced.  I'm about a -3 myope.  I wear mid-index comfortably, but poly and me just did not get along.

About the tinting of poly - as Pete said, raw poly will not tint at all.  If you want super scratch resistance, you have to settle for lighter tints.  The softer the coat, the better the tint.  Remember that ALL of the tint is on a thin little layer of coating on the back side, so don't hope for great sunglasses unless you are willing to sacrifice the scratch resistance.  Adding the tint to the manufacturing process was a good idea.  Unfortunately it did not catch on.  I'm pretty certain that trivex has the same inherant problems but does absorb tint in its raw form.  If you add scratch resistant coating, you have the same issue.

As to the matter of safety - when you drill anything, safety is no longer a selling point.  Drilling creates a weakness in the material that is measurable when compared to undrilled lenses of the same material.  If safety is an issue, don't sell drilled rimless.

There you have it.  $.02 worth, at least.  :D

shutterbug

----------


## Billy Brock

hello all, very interesting variety of posts on the thread.....here is a photo of my personal test between a Trivex  blank, concrete and the tire on my car

before Trivex came along, in my opinion there was not a better choice than poly, and I still beleive "choose the best product for the current situation"

thanks Pete for all the technical stats....... education is the key to helping me do a better job

B

----------


## Pete Hanlin

That's the best use of a Trivex lens I've seen to date!!!  I would encourage everyone to do the same!

(Sorry, I couldn't resist...)

This past year, I've been able to look at a LOT of failed lenses- of all materials, shapes, and sources.  I am more convinced than ever that proper processing techniques make all the difference in the world when it comes to how well a lens will hold up.

Long story short, _any_ lens can fail if it is processed poorly enough.  For example, if you have a Trivex or poly lens actually crack (I've seen both), take a long, hard, magnified look at the bevel of the lens.  My bet would be you will see several small microcracks in the edge of the lens.  This usually comes from a dull cutting surface and it creates a sort of "rip" in the edge of the lens.  This "rip" can develop into a crack- especially if the lens is oversized or otherwise poorly mounted (take a look at your glasses in a polariscope and look for areas of tension...  you will definitely be able to notice an oversized lens).

Happy processing, and keep using those Trivex lenses as speed bumps!!!
;)

----------


## Billy Brock

LOL   LOL  ! ! ......... good one Pete ! ........ "speedbumps"  ...........:)

I wish I could have used that speed lens under my tire on this time intensive design.......... the pictured poly lens was not very old when it split ......... (notice in the closeup it had been chamfered) ...... :(

I processed this poly Rx utilizing all the steps Pete & others have posted over the last few months & it still failed ...... (always occurs on the expensive stuff)

Recently technology has afforded us a wealth of alternative lens material choices............. IMHO, the patient would not have been inconvenienced had Trivex been the initial material of choice.

I stand by Pete in saying try to process the best lens material to compliment the frame of choice Rx.


B

----------


## keithbenjamin

Has everyone seen the impact test videos put out by Younger that RT mentioned? Regardless of whether or not there was any bias engineered into the test, the results are still pretty dramatic. Besides, who is to say whether a person in more likely to get hit in the eye with a pointed object or a blunt object?  :shiner: 

The links for the videos on the Younger site are dead, so I went ahead and posted them. You can see them via the link below.

(Pointed) Impact Test Videos 

I omitted the spectralite test. If anyone is interested, I can put that one up too.

-K

----------


## Chris Ryser

I wish I could have used that speed lens under my tire on this time intensive design.......... the pictured poly lens was not very old when it split ......... (notice in the closeup it had been chamfered) ......  


If you would have put a drop of *OMS "EDGIT" or "POLY EDGE POLISH"* into those holes, you would have sealed the microscopic cracks that you produced while drilling and NO crazing would have occurred !

----------


## Billy Brock

thanks Chris,

which one of the two products is the absolute best one for stopping poly from splitting ........... I'll try anything  ! !

This is another perfect example in my personal situation where Trivex has been the better choice ......... I don't have to hunt down fix me solutions for Trivex:  drill it, mount it & you don't see the job back again until it's time for a new Rx........... hopefully your chemical will make poly a drill it, FIX  IT   and ship it  product

appreciate the help !

B

----------


## Chris Ryser

which one of the two products is the absolute best one for stopping poly from splitting ........... I'll try anything ! ! 

Billy,

Actually they are both the same with the difference the "Edgit" contains color that fuses with the poly.

Send me your name and address by e-mail and I will send you a sample with a glass dropper to get it into the hole and make your trial.

----------


## Gov't Mule

I also have looked for the answer to the above question.  Colts Labs folks should know?  Why don't we ask them?




> 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...





> Even after all the discussion, people are voting for option number one.  (Trivex is more impact resistant and has more tensile strength than Polycarbonate)
> 
> Only three have voted for the correct answer (#2) , and one of them was me, so...(Trivex has less impact resistance but more tensile strength than Polycarbonate)


Pete Hanlin
St. Petersburg, FL
Essilor Lens Group




> A subsidiary of Essilor International, S.A., Gentex Optics, Inc. is a leader in the manufacture of ophthalmic lenses, specifically the revolutionary new polycarbonate lenses.


I am not too sure how revolutionary an abbe value around 30 and little 'spider-web' cracks on drilled rimless are.   I know that I always find this 'debate' redicilous.  I hope I am doing all this quoting and linking right...  Follow this link to find out what is known about the two lens materials:

http://www.ppg.com/chm_optical/trivex_ppg.htm

Another thing I know to be true is that if I owned an extremly large polycarbonate plant, I would be doing whatever I could to protect it.  Not to mention the fact that a Trivex Varilux Comfort would be one of the easiest lenses ever for a patient to adapt to.  Along with being extemely light weight, optically pour, and scratch resistent we now know, from reading the information in the link above, that it passes FDA drop ball tests @1.0mm CT and meets ANSI Z87.1 '89 standards.  Trivex is also the only material, other than polycarbonate, that passed the High Velocity Impact test.  So we know it is impact resistent.

Perhaps they have to try and change the name of it a few times before it will take off.  

Just some facts to ponder.

----------


## Shutterbug

Pete - the darn thing wouldn't let me vote.  Said I already did!  I'm afraid old timers disease has set in!

 :Rolleyes:  

To the post:

As to lenses causing the loss of eyes - it's almost never the lens at fault, but some other impact that the lens could not stop.  If you are hit hard enough to break a standard plastic lens even, you are going to be hurting.

 ;) 

shutterbug

----------


## Oha

Here's the link to the poly council.  Its a great site!

http://www.polycarb.org

----------


## Pete Hanlin

Wow, I hadn't visited this thread for some time.  I didn't realize there had been so many posts as of late.

I'm not sure where the "revolutionary new polycarbonate" quote came from.  I don't believe I made that statement (especially since polycarbonate has been around for decades now).

Regarding the cracks you have experienced, there is quite a bit of R&D being done right now to make those a thing of the past.  So far, they have determined that the cracking does not occur on uncoated polycarbonate lenses.  Also, the cracking occurs because of the microcracks created during edging/drilling (as Mr. Ryser has noted).

Just to revisit an old, tired subject, however...  Trivex is- IMHO- never going to "take off" as a lens material (and I don't care what you call it).  Not because there will be some conspiracy to keep it off the market, but simply because the material does not offer that much of a benefit over existing products that are produced at lower expense.

Additionally, it is not as if Trivex doesn't have its own processing difficulties.  The material heats up quite a bit when edged and takes longer to process.  In a high volume laboratory, this is a serious impediment.  We've seen accounts that have tried to switch some business to Trivex- only to switch back to polycarbonte.

Now, when someone with the obvious experience and technical expertise of a Billy Brock has difficulty with a material cracking, does that lead me to believe there _is_ a problem to address?  Sure enough!  I believe we need to continue to find ways to reduce the heat involved in drilling and addressing the microcracks that result.  However, I still maintain that polycarbonate is a very easy material to properly drill.  If you are experiencing massive problems with cracking, you probably aren't drilling with proper technique.

PS- I have some pretty pictures of Trivex lenses that have crazed after drilling as well... its not just a poly issue

----------


## Shutterbug

d

----------


## keithbenjamin

Most thought provoking Shutterbug! I'll have to say I agree completely ...I think. :D

----------


## sticklert

Hey Pete,

Why don't you post those pretty pictures of Trivex?  I am sure I am not the only one who would like to see them......

----------


## Chris Ryser

> *sticklert said:* 
> Hey Pete,
> 
> Why don't you post those pretty pictures of Trivex?  I am sure I am not the only one who would like to see them......



Could become a very heated thread      ....................   the spokesman of another large corporation is challenging the competition to a debate.........................


To bad that there is a quite week coming up because of all the poeple taking time off before the long holiday weekend.

----------


## Gov't Mule

Here are some examples I was able to find... Since I don't know how to do this attachment stuff, bear with me.

----------


## Gov't Mule

Let me try this gain

----------


## Gov't Mule

Next two are Poly.

 

 

This last one is a Trivex lens where the frame broke.  We simply pushed out the bushing and remounted lenses into new chasis.  More to come... and I personally challenge anyone to show the opposite of these pictures to be true on drilled rimless.  

I strongly caution you all to remember where you are getting your information from on the Poly v Trivex issue.  As I have stated before, if I owned, or worked for a company that owned, an extremly large Polycarbonate manufacturing facility, I wouldn't be too warm to the idea of promoting Trivex.  My two cents worth.

----------


## Pete Hanlin

I strongly caution you all to remember where you are getting your information from on the Poly v Trivex issue. As I have stated before, if I owned, or worked for a company that owned, an extremly large Polycarbonate manufacturing facility, I wouldn't be too warm to the idea of promoting Trivex. My two cents worth.
I agree that one must consider the source when receiving information on any product.  After all, I do work for a company which specifically chose _not_ to manufacture Trivex lenses.  Such a "strong caution," however, seems to imply that false information has been provided...   

Factually speaking...
Trivex is a material that has a lower specific gravity than polycarbonate.Due to polycarbonate's higher index of refraction, Trivex and polycarboante lenses of the same power will have the same weight.When ground to the same center thickness, a polycarbonate lens will be thinner than a Trivex lens of equal power.Using the "drop ball" test, polycarbonate performs better than Trivex- because polycarbonate's impact resistance in this test is less affected by SRC and ARC coatings than Trivex.A test can be devised (using a weighted, pointy projectile) where Trivex outperforms polycarbonate.Trivex performs very well in drill mounted applications, however, so does polycarbonate.  It can be demonstrated that, when mounted properly, polycarbonate has excellent properties for drill mount applications.The cause for polycarbonate lens failures in drill mount applications seems to be SRC and ARC (uncoated lenses do not fail).  Micro-cracks in the coating have the potential to propogate into full lens failures when not removed by chamfering.  These coating cracks can be observed on drilled Trivex lenses as well.

Whether or not I work for a company that has made an investment in the fastest growing lens material of the past decade (polycarbonate) doesn't alter the fact that Trivex is neither thinner nor lighter than polycarbonate in real application.  It also doesn't affect that fact that Trivex is available in a relatively small number of PAL designs, and costs more than polycarbonate.  

The _only_ thing that has been a positive for Trivex is its suitability for drill mounting- and it does appear to be a good material for this purpose.  However, I would urge the optician to excersize _strong caution_ when a Trivex manufacturer tells them Trivex is the only material suitable for drill mounting- this is simply false and misleading.

In real life, polycarbonate and pretty much all of your high index materials perform very well in drill mount applications.  Naturally, their performance will be greatly affected by the quality of the drill mount.

If you are using Trivex and feel it is providing the best combination of value, cosmetics, and safety for your patients- well, keep using it.  Trivex is by no means a "horrible" product.  In my opinion, however, it offers very little in the way of added value to the patient or the eye care professional.  

I admit that some people who I respect very much claim that there is really something to this Trivex stuff (they "see better" through the lens, or it "drills better").  All I can go by is my own observation, however, and my lensometer, eyes, and drill don't tell me that this material offers anything that justifies its added expense for a 1.530 index product.  For my money, I will invest in a readily available, proven product that is light and thin- polycarbonte.

----------


## keithbenjamin

In your comparison Pete, you basically outlined two very equal lenses, in your eyes. The concensus does seem to be however that Trivex does drill better and is better optically, which you seem to have a hard time conceding. 

As far as price, if you're not comaparing apples to oranges there is little, if any difference. You have to remember that Phoenix is spheric and the Trilogy is aspheric. Between spheric poly and spheric Trivex (apples and apples) there is NO difference in price. Between aspheric poly and aspheric Trivex the difference is FAR LESS than indicated in other posts.

So, in summary you have two pretty equal lenses in terms of thickness, weight and safety. Trivex is probably better for drilling, is certainly superior optically, and is easier to tint. Trilogy comes with a lifetime guarantee against drill mount cracking. There is little, if any difference in  price when comparing apples to apples. 

...bang for my buck goes to Trivex.

----------


## Chris Ryser

> *Shutterbug said:* 
> * If you want super scratch resistance, you have to settle for lighter tints. * 
> 
> There you have it.  $.02 worth, at least.  :D
> 
> shutterbug


* WRONG:

By using MICRO-TINTS you can go up to 2% to 3% transmission on a Poly with a hard tintable coating in 5 to 8 minutes of tinting time.

Uncoated Trivex will tint by any method but the tint comes off by applying any solvent as lens cleaners containing Isopropyl which most of them do. The only way Trivex is colorfast is by having a coating applied*

----------


## Gov't Mule

"I admit that some people who I respect very much claim that there is really something to this Trivex stuff (they "see better" through the lens, or it "drills better"). All I can go by is my own observation, however, and my lensometer, eyes, and drill don't tell me that this material offers anything that justifies its added expense for a 1.530 index product. For my money, I will invest in a readily available, proven product that is light and thin- polycarbonte."

Wow!  And to think we are all trying to give people the best possible vision.  It is ridiculous to think that it is not worth an extra $1.50 for better vision.  

Perhaps I had this all wrong.  

For awhile there I forgot we were all in this to make money, not to offer the best possible lenses to the final consumer.   Maybe this is what separates the French and their sympathizers from the rest of us.

Here is another thing to consider.  Let's say we were all in the hearing aid business.  Would you want to offer the hearing aid that allows there to be some muffled sounds, or would you want to offer the one that has nice crisp sharp sound?  I believe you get the point.  

Thank you for the debate, I consider my job here finished.

----------


## Billy Brock

Pete has always stood by his  motto: choose the best product for the job for each individual situation......  I appreciate all  the help he has given me personally to help process my poly Rx's ...... thanks and the poly orders do seem to be doing somewhat better by utilizing the technical info you have so kindly posted ............. thanks also to Chris Ryser for sending me the chemical poly polish. I'm with Pete on trying to choose the absolute best material based on optics, mounting selection & Rx.


 There is a special  factor in my personal opinion only that DOES  justify any additional fee for Trivex material: in over 26 months of active use I have never replaced one single lens due to material failure of any sort .......................   it sure makes me happy to stand in line at the bank to deposit  $ $ $ instead of sitting in the banker's office begging for a loan to cover lost expenses due to lens material failures.

     "IF" the patient receives better visiual accuity ,in my opinion that's just a bonus...................................... as far as "easier" drilling goes,  depends on how you define "easier"  ? ? ? .................................  my personal definition includes: I don't have to be careful, I don't have to chamfer edges, I don't have to use nylon washers to cushion , I don't have to worry about any chemical compatibility, I don't have to use chemicals to retard splitting, crazing & cracking, I don't have to worry   during the mounting and pre-alignment phase....................... that being said , Trives  IS  easier  (in my situation) to work with  because I'm confident it will not be returned for a material failure redo.................. bottom line, my choice for Trivex in drill mounts rests with the "ease" of processing and no failures ........ as always this is only my personal observation & opinions based on my extended use of PPG products.

hope everyone had a nice holiday season ...... looking forward to 2004 with all you Optiboarders


B

----------


## Laurie

Hello Everyone,

Maybe I skimmed through this thread too quickly, but I did not notice anyone talking about the ABBE VALUE of TRIVEX...MUCH better than polycarb!

Of the five specular aberrations, clients will subjectively complain the most about chromatic aberration.  Of the aberrations, we can adjust for 4 of them through lens design...the 5th (chromatic aberration), cannot be adjusted for...it is inherent in the material.  The best we can do is choose lens materials with the lowest amount of chromatism, which is indicated by a high abbe value.

A high abbe value indicates low amounts of chromatic aberration (chromatism).  

Trivex is better both optically and practically (processing).  

Pete, you know I love you like a brother...but are you still singing the praises of polycarb over high index, and now, trivex?

Must I report you to Clifford Brooks and Moe Jalie?

smooch,

; )

Laurie

----------


## For-Life

I want to address the abbe debate.  I saw previously that someone wrote that they wore ploy and they got tunnel vision.

Over the last few years I have worn 1.67, 1.6, CR - 39, Trivex (Phoenix), and Poly (Essilors Airwear aspheric and non-aspheric).  I am currently -5.50 OU.

I have not had difference in my vision in either of these products.  Now not having any astigmatism, the aspheric or non-aspheric lens will not really have an effect.  But I have had no colour deviations, nor any vision problems.  We have used the Airwear Aspheric lens on a lot of our customers ranging up to 11 diopters, and the 1.67 (which has the same abbe value) up to about 13 diopters.  We have not had any vision problems, and if anything have had more success.  Actually recently I had someone in who had glass lenses and he had an RX of (it is not the exact value, but of by maybe only a quarter diopter or 10 degrees)

-7.00 -7.00 x 090
-6.00 -7.25 x 090

He developed a cist on his nose from the weight of the glass, so we put him into the Airwear Aspheric.  He said it was the best vision that he has ever had in his life (he did not have a prescription change from his last pair).  So I honestly believe that the Essilor Airwear Aspheric (we always do it with Crizal) is one of the best materials on the market, even though it has an abbe value of 32.  

The only problem is the cracking in 4-points.  But I am going to try edgit and poly edge polish.

----------


## For-Life

I saw that the survey bumped this post so I will give you an update.  I have been using Edgit on my poly rimlesses and I have not had one crack since.

----------


## Tjcjdc9462

Trivex tints very well.  You can do gradients and sun tints just like CR39.

----------


## dadoody

The optician told me they think polycarbonate is better for my 3 piece mount rimless glasses. They say it is softer and gives better than Trivex, so they say it won't crack.

----------


## Tjcjdc9462

That is absolutely incorrect.  The only reason they are telling you that is because they don't sell trivex and they don't won't to lose a sell.  Take it from someone with 15 years experience who sells approximately 10 pairs of Silhouettes a week alone, you will regret your purchase if you get poly.  My advice is to keep shopping.

----------


## For-Life

We do a lot of poly in a rimless.  You just have to use a good product to seal in the cracks.  If you use that then you will have no problems.

----------


## blackbirdy4444

_




 Originally Posted by 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)?_
> ...





Clearly your handle on the various manufacturing technologies of monomers etc is great.  However, you fail to mention the fact that the fabulous way in which poly is made directly results in a great deal of internal stress that creates yet another reason that human beings do not see well out of it.  Low ABBE, heightened amounts of internal stress, poor coating capabilities....

No offense here, but Essilor's main reason to promote poly as heavily as they do is because it costs them the least.  They charge more for it than other superior materials and purposely mis-market it.  The FDA gives Trivex and Poly the SAME impact rating of >60x that of CR39.  That is the highest it goes.  Essilor owns and manufactures more poly than anyone, therefore they promote it.  Not because it is good for the masses.

Drilling a poly is a huge mistake.  It is not a matter of ''IF" it will crack, it is a matter of "When".

I am currently working for HOYA and have helped numerous private practitioners transition away from this horrible material.  The Triangle (so to speak) of perfect lens balance good ophthalmic optics, light/thin, and impact resistance.  This makes Trivex and its derivatives the best possible lens material to put MOST people in.  In higher power ranges, patients deserve to be put into a 1.67.  Poly has in many respects become the 'poor man's' high index because we can buy it cheap and surface it to a 1.0.  Would you like to comment on how good an idea that is?  Why don't you mount ANY 1.0 poly in a full metal frame and then watch it flex with the last turn of a screw driver.  And then we wonder why people don't see well.

In the past, there were times that availability made it tough to take a person out of poly, but those times are gone.  

Your explanation of poly and its manufacturing characteristics is really cool, and clearly well informed.  I don't really feel it is fair though when your remark that poly is "a better way of life".  People don't see well out of it!!!!  They now have an alternative that is just as safe.   I don't understand why you would market an outdated technology at full price!  Would you pay full price for a ten year old car?

----------


## Judy Canty

Ummm...5 year old thread and counting.

----------


## chip anderson

Why do we even rate or care what the tensile strenght of lenses are?   No one is going to pull them apart.  Has nothing to do with impact resistance.  Has nothing to do with scratch resistance.  Has very little if anything to do with distortion in manufacture or mounting.

Chip

----------


## HarryChiling

I know this is an old thread, but I have to ask.  When poly is compared to trivex in impact resistance, is the base curve an power taken into consideration?

Reason I ask is, the flatter a curve gets the less impat resistant the lens becomes no matter what the material.  Since poly has a higher index that trivex the poly lens would aslo have a flatter base for the same power as a similar trivex lens would.  Has this been factored in or are we looking at a standard base across all materials?

BTW, I choose wrong.:hammer:

----------


## DragonLensmanWV

> I know this is an old thread, but I have to ask.  When poly is compared to trivex in impact resistance, is the base curve an power taken into consideration?
> 
> Reason I ask is, the flatter a curve gets the less impat resistant the lens becomes no matter what the material.  Since poly has a higher index that trivex the poly lens would aslo have a flatter base for the same power as a similar trivex lens would.  Has this been factored in or are we looking at a standard base across all materials?
> 
> BTW, I choose wrong.:hammer:


In choosing wrong, you chose wisely.:D

----------


## hcjilson

I haven't checked with Pete lately...but now that Essilor has released Definity in Trivex, perhaps he has upgraded his opinion of the product.

----------

