We dont realy use poly and triwex in Denmark, but i just made a par for my self in triwex,
and is very imprest whit the lightnes, and i am thinking about using it more.
what do i have do to know before i start using these "new" materials.
pleas tell me all the "Cowboy tricks"
Best regards
Peter
First off, don't use poly, nasty stuff, not fit for human consumption..... Especially when Trivex has all the strenght of poly and the clarity of cr-39....
Sure Trivex is great stuff...........and now for the rest of the story.Originally Posted by kentmitchell1961
Trivex is great stuff as far as vision goes.......and it also makes your lenses heavier and more expensive.
So make your choice as to what your priority is.
+1
Totally agree.....we rarely did poly jobs in our 26 years in this town. Only if a patient insisted, or one lens to match up. We often had patients we moved into Trivex (Phoenix for us) who were amazed at the improved clarity. We had a large clientele of those who came for custom rimless product. While Poly would starburst on the screw holes, as well as had one split (while the patient was wrestling with his son), we had MANY stories from patients on the durability of Trivex. One gentleman was working on his 29,000 pound bucket truck, took them off and laid them on the ground (single vision) to see up close, then got up to run it forward and see how his repair worked. Rimless frame broke one part, lenses did not break any where. I just recently disposed of the Flexon case a patient left with her rimless Flexon in it on her car and drove off.....found it later on the highway, smushed very thin, and obviously beat up. The glasses were bent but nothing was broken at all. Not the Flexon frame, not the lenses at all. We did have to redo them as the A/R got smudged off right in the center of each lens from the continued process of being run over. I have story after story after story of rimless glasses with Trivex that have withstood horse trailers, 280 lb men stepping on them, etc. We always used the verbiage that it turned a 'use with care' pair of glasses into a 'sturdy pair of eyewear.'
They are a harder lens, so depending on how updated your edging system is, you may have difficulty getting precise shapes cut, but there's no reason to use Poly in my estimation, once you've tasted the sweetness of Trivex.
Mother Theresa - MRS. "CoolOptican"
Most of our so-called reasoning consists in finding arguments for going on believing as we already do. —James Harvey Robinson
News to me. I've heard of Trivex being thicker than poly, but was under the impression that it was more lightweight.
Same here.....in fact, it's supposed to 'float on water' I thought??? Just included all my old sample lenses with an equipment sale, so I can't test it out!
Mother Theresa - MRS. "CoolOptican"
Most of our so-called reasoning consists in finding arguments for going on believing as we already do. —James Harvey Robinson
You will get widely varying opinions on this. Poly has worked very well in my practice. Trivex is good, but it is way more expensive in the US than poly. Trivex, while it may be lighter, is thicker. Trivex may hold up better in drill jobs, but it will reduce how high you can go on the Rx especially on the minus side and still have it look decent.
So, pick your poison.
Love Trivex. If the power in a drill job is too high for Trivex, we move to 1.67 skipping poly altogether.
+100
Mother Theresa - MRS. "CoolOptican"
Most of our so-called reasoning consists in finding arguments for going on believing as we already do. —James Harvey Robinson
Just t clear up some misconceptions.
Trivex is soft not hard, hence the impact resistance.
Trivex can and can't float on water. Water has a weight of 1g/cm3 Trivex is 1.11g/cm3 so it will sink in water, but the surfaface tension of water will allow a lens to float if placed properly. Poly with a weight of 1.2g/cm3 has the same properties in water.
Trivex is interesting to process, it will melt when surfacing if too aggressive and cut dry. While edging I prefer to rough edge wet with a trivex wheel which has cut outs on the wheel to allow for the lens to stay cool while cutting. Then the finish or bevel wheel is best dry with a wet last cycle to put a low luster polish on it. Without a good routing edger it is tough to get sharp shapes without a new dressed wheel. Drill holes don't experience the same elongation or star cracking as poly so is our preference for drilling. It does have a slight hue barely noticeable. Trivex can be tinted easily especially compared to poly and the material itself allows tint between the material matrix rather then poly which only allows tint of the top coat. Tint with a low temperature setting to avoid destroying any hard coats.
Poly has been traditionally cheap for the index, commonly refered to as the poor mans high index. This has lead to it's proliferation amoung chain stores which prefer materials and lenses based on a specific cost benefit analysis with optics and carity taking a back seat. For SV and for low to moderate prescriptions poly is a suitable choice. Poly is very susceptible to checmical degradation and at low powers when surfaced thin can warp and crack due to flexture.
Trivex has great clarity with a high abbe value of 43 to 45 depending upon manufacturer, whereas poly is at a 30. Once again as long as the power is moderate and the lens does not require off axis viewing such as PALs or Multifocals poly is an acceptable choice. One poster here has an interesting approacj which I admire, Barry Santini suggests that with FF processing and proper OC placement some of the compounding effects of aberrations can means a higher acceptance rate amoung clients when fit with Poly or other low abbe lenses.
Hope that helps in your quest to make a decision on which materials to use and when.
Thanks for pointing this out, Trivex w/ HC is NOT more scratch resistant than CR-39 with a basic $2 hard coat is.
There is some quote creep going on here, if you look around the world you will find listing for Trivex for a 43-45 Abbe, so I checked out some websites and did some testing myself. In the tests I ran, 43.6 was the highest Abbe I could verify for any Trivex. Whoever was quoting a 45 (and they are, not your fault) I asked them to send me independant test results to verify their numbers, and NONE OF THEM COULD. If anyone has actual test results for a Trivex at 45 I would be interested in seeing them, then I will believe you.
And some Polys did test higher than 30.
Last year, I looked around the world at Hoya's websites they quoted different numbers in every country for their 1.70 both in Abbe and Spec. Gravity. Quote creep.
Both true, trivex is slightly thicker than poly because it has a lower refractive index (1.53 vs 1.59) but since trivex is less dense than poly the thicker lenses are still lighter.
Except poly has good enough optical quality that they perform quite well on weaker prescriptions. One of the questions I've never gotten a definitive answer to is at what power is it worth the cost to upgrade from poly to Trivex?
????You did some testing yourself????
Well zeiss claims that their trivex has a 45 abbe and to be honest with you I don't have access to the equipment to verify any of their claims and in the past I know for a fact that none of these companies are going to give you access. Even when they print in their ads that resuts are available.
Secondly on that continent NXT was available before trivex (same thing different name) The claim is that NXT has an abbe of 45.
Third being in the part of the world that the poster is posting from I don't know what effect their reference wavelength is going to have on trivex's abbe value.
Please do not attempt to put words into my mouth, I said nothing to compare CR-39 to Trivex and I discussed nothign about hard coats, those are your words not mine.Thanks for pointing this out, Trivex w/ HC is NOT more scratch resistant than CR-39 with a basic $2 hard coat is.
On another note bare CR-39 compared to bare Trivex is going to be a harder material and therefore a bit more scratch resistant. With hard coats both CR and Trivex are comparable in scratch resistance, both materials have enough scratch resistance in their uncoated state that they would be acceptable to dispense uncoated, though not recommended.
To the original poster, while your looking into new materials get prepared for Trivex's cousin Tribrid to be more available in the near future. 1.6 index, 41 abbe, and 5x stronger than other high index lenses. My understanding is that the same nitrogen enriching process was used to enhance a higher index eurathane. My guess is over then next so many years we can expect to see all eurathane based hi index lenses enriched with nitrogen to increase the impact resistance.
Wrong! Trivex is lighter than Poly! Look it up.
Where would I find this ?
You can start here...
http://www.laramyk.com/resources/edu...polycarbonate/
But PhiTrace answers the question in post #10
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