Essilor prog. lenses? Why don't they offer Trivex?

**jeffsoptical** · 09-11-2006, 09:50 AM

I use a lot of Essilor progressive products and I don't understand why they don't have them in trivex. I have a smart drill II digital and I love it. Chuck from Smart drill lab says to use trivex first, then 1.60, 1.67 or higher index for my drill mounts to avoid stress cracking in drill mounts. He said that the resolution poly is good to use but not other poly. He said that even CR-39 is better than poly.

I have noticed since I've been doing my own drill mounts that Poly does fine in drill mounts that don't use screws to hold them together. The silhouette style compression mounts do very good with poly. I think because there is less stress on the drill holes. I always chamfer the drill holes after drilling, so that is not the problem.

An Essilor rep. told me to use 1.67 MR-10 resin for all drill mounts, but chuck told me that 1.60 works just as well. I don't want to charge my customers a 1.67 price if I can use 1.60 for about the same price as poly. Please give me your input and explain why essilor isn't getting into the Trivex market.

Also is NXT which is 1.53 index the same thing as Trivex?

P.S. What is the best glue to keep screws from loosening in drill mounts?
Jeff

**For-Life** · 09-11-2006, 10:28 AM

From the Essilor rep who posts on this board, Essilor does not use trivex, because it just really does not fit in well with the product line. Other than drill mounts why would you use it?

Drilling poly has been a question in the past. The cracks that develop have nothing to do with whether it is a screw or compression mount. These cracks originate in drilling and expand over time. There is a solution, use a drill sealent. OMS has a few. Here is their Edgit product:

http://optochemicals.com/poly_edgit.htm

You drop a tad into the hole and it will then not crack. Simple, inexpensive, and now you can use poly.

**Chris Ryser** · 09-11-2006, 11:34 AM

Originally Posted by For-Life

These cracks originate in drilling and expand over time. There is a solution, use a drill sealent. OMS has a few.

And here is another one:

http://optochemicals.com/products/info_drillseal.htm

**Traci** · 09-11-2006, 11:50 AM

I agree. I use Trivex whenever possible and 1.6 alot! I don't like to use 1.67 when I could use 1.6 even for a non-drill job. But sometimes feel forced to if I choose to use Varilux product - Ellipse, Physio, (same with Ziess on their new products). I wish that even if they don't make trivex that they could at the very least offer 1.6 Index in more of their products.

**Jacqui** · 09-11-2006, 12:08 PM

Originally Posted by jeffsoptical

Also is NXT which is 1.53 index the same thing as Trivex?

Jeff

Yes

**hcjilson** · 09-11-2006, 12:36 PM

The main reason is that Essilor has invested heavily in polycarb production facilities. Trivex is a competing product, but Essilor in their wisdom, has come to realize the value of Trivex. I have heard "unofficially" that they will be releasing a product in Trivex by years end. (Definity) Yahooo! My prayers have been answered!

In answer to For Life,

For Life said: "Other than drill mounts why would you use it?"

First, its lighter in weight!
Second, it is more impact resistant ergo, safest!

and then we can talk drilling,

Third, it is drillable 100% of the time at no risk other than putting the holes in the wrong place or size! Source for that is Billy Brock who has done hundreds with no failures.

**For-Life** · 09-11-2006, 01:06 PM

poly is lightweight and safe too

**Grubendol** · 09-11-2006, 01:20 PM

Originally Posted by For-Life

poly is lightweight and safe too

and a pain to clean the grooving on ;)

**Cherry Optical** · 09-11-2006, 04:17 PM

Originally Posted by For-Life

poly is lightweight and safe too

Also, Trivex (-) powers come standard with 1.0 CT.

Adam

**For-Life** · 09-11-2006, 05:15 PM

Originally Posted by Cherry Optical

Also, Trivex (-) powers come standard with 1.0 CT.

Adam

doesn't poly.

Anyways, I am Canadian, so with us pretty much everything, except CR-39 comes witht he standard 1.0CT

Either way, isn't poly still thinner?

**fjpod** · 09-11-2006, 05:20 PM

Make sure your drill bit is SHARP. A dull bit will create microscopic cracks along the edge of the drill hole. The cracks will spread later under normal stress, strain, and temperature changes.

RT · 09-11-2006, 07:20 PM

Either way, isn't poly still thinner?

Nope. Not always. It's easy to engineer cases where it's not, particularly when the standard center thickness for poly from many labs is 1.5 mm, and for Trivex is either 1.3 or lower.

For example, for drill and and groove mounts in lower powers (you know, the powers that make up 90% of the jobs in North America), the edge thickness needs to be a minimum. So for poly and other higher index materials, you end up having to have a THICKER center to hit the minimum edge thickness. So the poly lens has the exact same edge thickness, but is thicker at the center, has greater volume, and due to its higher specific gravity, weighs quite a bit more. But at least the power is low enough that you won't notice the low Abbe value.

**Barry Santini** · 09-12-2006, 06:21 AM

Originally Posted by RT

For example, for drill and and groove mounts in lower powers .... the poly lens has the exact same edge thickness, but is thicker at the center, has greater volume, and due to its higher specific gravity, weighs quite a bit more.

"...weighs quite a bit more."

More? as a percentage....yes, but in fractions of grams, some nose pad changes will amount to "more".

Be careful of comparatives....they can be misleading

Barry Santini, ABOM

**For-Life** · 09-12-2006, 09:08 AM

Originally Posted by RT

Nope. Not always. It's easy to engineer cases where it's not, particularly when the standard center thickness for poly from many labs is 1.5 mm, and for Trivex is either 1.3 or lower.

For example, for drill and and groove mounts in lower powers (you know, the powers that make up 90% of the jobs in North America), the edge thickness needs to be a minimum. So for poly and other higher index materials, you end up having to have a THICKER center to hit the minimum edge thickness. So the poly lens has the exact same edge thickness, but is thicker at the center, has greater volume, and due to its higher specific gravity, weighs quite a bit more. But at least the power is low enough that you won't notice the low Abbe value.

well of course

**Cherry Optical** · 09-12-2006, 11:33 AM

Originally Posted by Barry Santini

"...weighs quite a bit more."

More? as a percentage....yes, but in fractions of grams, some nose pad changes will amount to "more".

Be careful of comparatives....they can be misleading

Barry Santini, ABOM

Barry,

You are correct when it comes to grams. However, to be correct we must agree that Trivex is the lightest material. The logic of "it's just grams or millimeters" can be used to describe the differnce in weight or edge/center thickness between lens materials.

Maybe a way to look at it is like the Periodic Table of Elements. The differences may be small between the elements (in this case lens materials) but there is a differnce non-the-less.

Another thing I haven't seen anyone state yet about Trivex is the outstanding chemical resistance and the availiablity of the industries must scratch resistant AR coating, HOYA Super HiVision.

And while I'm at it. Those of you that are into the Free-Form progressive technology, you can soon (or maybe even now) get the Kodak Unique Free-Form design in the Trivex lens material. For a material that there is 'no-need for', plenty of non-french lens manufacturers seem to be finding a niche for the material.

Adam