Trivex
1.67
1.60
Polycarbonate
1.74
cr-39
Trivex
1.67
1.60
Polycarbonate
1.74
cr-39
in order of best to worst
trivex
1.60
1.67
1.74
poly
cr39
I will only use Trivex, 1.60, and 1.70 depending on correction.
Do not vote out Poly because you did not know.......................
The most durable and resistant, plus least expensive lens is still Polycarbonate.
If properly mounted as per instructions of the main sponsor of OptiBoard, "Vision Ease", Polycarbonate lenses are totally trouble free lenses in rimless drill mounts and not as the survey vote above indicates.
If optical labs that are mounting polycarbonate lenses into "drill mounts" and are not doing it the recommended way, one should not blame a material.
One should use a lab and technicians that know what to do, to produce a job with a material that is perfect and will not craze and break and of which bullet proof car windows are made.
Read and follow the proper instructions : http://www.vision-ease.com/Portals/V...lessMounts.pdf
When was the last time your tried to do what they suggest? It is poor info at best!
I do 70% drill-mounts and zero % are poly! We do 95% trivex and would do 0% drill-mounts if we had to drill first and then get them ar coated; that is not practical and a waste of time. The only reason to use poly instead of trivex is to save money!Originally Posted by Chris Ryser
This sheet should have a disclaimer that if you have all this time for one job, you might need another way to do business.
there are a few things to consider. first is the prescription. for minus jobs with some edge thickness, i like 1.6 (mr8) and 167 (mr10), these are very resistant to breakage. for low minus to low plus trivex is great, but you should inform clients about the way these slightly yellow over time. i dont like poly in drills very much, its a crap shoot and the stress cracks around drill holes is a PI the A.
I have no yellowing over time on trivex, it depends on the scratch coat used. We show clients how poly starts out yellow and trivex is much clearer with better optics. You might find trivex is suitable for all RX's from -4 to +4, it is so light that it feels best at the end of their nose.
We put folks in the lightest weight lenses, not the thinnest for the RX. We have happy folks in a -4 trivex with great optics.
Find a new lab if your trivex is turning yellow.
Thanks for the reply Craig, I've used Hoya Phenix and younger too. I've tried it from at least 4 different sources in Canada. Generally people are not bringing them back and complaining, but 3 or 4 years or so later, the lenses come back in decent shape but absolutely yellow-tinged. I've discussed with sales reps here from a couple of labs and they acknowledge the issue. I'd love to know what they may add or do differently to trivex in your region, because for sure your clients will be more UV exposed than us pale white Canadians who get little sun....
I just replaced a set of 6+ year old set in my glasses today and they are slightly yellow, but it has been over 6 years.
It is only noticable on a white piece of paper. My lenses are coated and cured thermally, mabe you have a UV coating that is continuing to yellow over time?
Yellowing can happen to any lens if the coating is UV cured.
All things considered, Trivex is presently the best material for ophthalmic lenses.
1. Dispersion...............Medium Low.
2. Weight....................Very low.
3. Safety.....................Very High.
4. Thickness................Medium.
5. Chemical resistance..Very high.
5. Availability...............Medium high.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
By sealing the the inside of the drill holes there are no more stress cracks on poly.
optimensch.....................obviously you did not look at the link in my above post. The problem with stress cracks on poly has been solved a few years back.
By sealing the the inside of the drill holes there are no more stress cracks on poly. Have them done by a lab that does do the sealing or do it yourself. It's not hard to do and not expensive either.
The drill holes in poly tend to stretch or elongate to the point where the mounting becomes loose. Another reason not to use it.
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
"The most durable and resistant".............compared to what?
"Least expensive"..................compared to what?
I do not have anything to sell to fix its shortcomings, so I may not be understanding your statement? Could you elaborate?
+1!
B
I prefer 1.60 over Trivex, it finishes cleaner and no one complains about how thick it is. Many manufactures recommend 1.60 for their rimless frames as well.
I agree with the statement of poly holes enlarging. Trivex is an excellant choice and along with the MR8 and MR10 materials which have a higher tensil strength than poly, you have 3 very good choices.
Here is a picture of the frames I have.
I have a fairly high prescription (-9.00) and I have a pair of small (46 eye size) compression mounts (not the ones with the screws) made up with 1.67 index, premium anti reflective coating, and grey transitions. I have had zero problems with the lenses cracking from wear or getting loose or wobbly. In fact, the lab did such a fantastic job with them, I have never been happier. :)
Last edited by EyeSeeYou; 02-25-2013 at 03:50 PM.
Trivex
How about strain...............................
Now that we had plenty posts (18) on which lens material is best suited for rimless drill mounts and Trivex seems to have won the "Oscar",
it is time to let you know that most have forgotten the original material of rimless drill mounts ---------------> GLASS
Anybodythat is still around from the times when glass was the only material available for rimless frames, from "Numonts to Wilsedge" can certify,
that properly mounted products, where the secret for a long life of the product, and any type of breakages was accidental or bad treatment by consumers. You could not blame the material, you had to blame the workmanship.
Every optician had a polariscope to test the finished job for tension and if there was any, it went back to the lab to correct it. These days the holes are drilled by automatic devices who work computer driven without any finger tip feeling. I have not seen on OB that anybody even checks for strain on the lens when freshly mounted.
Chris,
I've got the cross polarizers top drawer and pull them out pretty regularly. It is interesting sometimes to check the tension overall - I believe frame-induced tension is a problem in a lot of cases, especially high index, flatter-base curve lenses, mounted into frames with a curve-mismatch. Most optical frames are fit with 5 or 6 base demo lenses and our lenses are mostly flatter than that. I have a feeling that the fanciest digital lenses are the MOST susceptible to this tension, and the performance of the product is affected more than the old "grinder" lenses. So yes, drill holes need to be checked for tension, but the overall lens too.
You should have included 1.70 in your list. The Thindex 1.70 from Optiboard sponsor Vision-Ease has excellent surface tensile strength and is suitable for drill mounts.
Me, Chris, or I could not do CR 39 in plus.
b
Yes...glass was the first material to be used back then and l really appreciate that it worked, but nowadays don't you think safety also plays a huge role. People are so busy these days and sometimes care is the last thing on their mind...so l still vote for trivex.
I drill about 4 pairs a week in PC (I don't sell, I just fill orders, don't give me any crap.) and very rarely have a problem. Its been a few years since I've seen cracking and I don't even use the Vision-Ease method. I edge my uncut coated with the Evil Empire AR, slap the in the Smart Drill, tap my (sharp) twist drill though at ~10,000RPM (about .5mm at a time), bevel the inside of the holes, and mount with the frame pieces flush to the front of the lens. This sets us up quite well, the final step is to adjust the frame properly so that there is no strain on the frame while wearing them, and to educate the Pt on the delicate nature of their new 'optical Jewelry'. We do a vast majority of compression mounts, and I don't usually check them for stress. The odd bolt together frame comes through and they get tuned in the polariscope to minimize stress caused by the hardware, also plastic top hats and washers galore.
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