1.6 material or Poly ??

[beejay]

Dear Friends,

I would like to know which is better in terms of impact resistance. For rimless frame, what should I suggest, poly or 1.6 material. I heard that 1.6 materials are impact resistant material suitable for rimless. Kindly advice

Regards
Maju

Atleast here in the Indian market place. The most widely used lenses for rimless are poly. Essilor does Airwear in 1.59 index. Check them out.
Benny

[DragonLensmanWV]

All polycarbonate is 1.59 index, Essilor does not make theirs any different, just more expensive. For drill mount lenses, at my place they ONLY get Trivex, nothing else. Have never had a single breakage or crack.

[sharpstick777]

Most rimless frame manufactuers recommend the MR-8 1.60 because it has very good tensile strenght, but the patient appreciates the thinner lenses.

I also think 1.60 finishes cleaner than Trivex. With an ABBE of 42, the advantage of Trivex is very very small.

[DragonLensmanWV]

Am I the only one who's tried 1.60 in drill mounts and had them break?

[fjpod]

We do OK with 1.60 in drill mounts...but we also do fine with poly. We just hardly ever see cracks with OUR work. We do see it frequently with work patients bring in from other sources. I attribute it to our drill-edger (NO 7e).

Would you really do a -4.50 drill mount in Trivex? Too thick.

[DragonLensmanWV]

I did a -15 in 1.70. (they were mine) Tricky part was drilling into the lens just enough to seat the frame. The back of the lens was undrilled. Then I had to invent a compression plier to mount them with.

[fjpod]

My optician complains that Trivex seems to drill unevenly. More bushings come loose even though they seem to fit well originally.

[beejay]

All polycarbonate is 1.59 index, Essilor does not make theirs any different, just more expensive. For drill mount lenses, at my place they ONLY get Trivex, nothing else. Have never had a single breakage or crack.

As I said earlier, this is the most commonly used Poly in the Indian market. And its not that expensive here in India.
Cheers.

[Java99]

Am I the only one who's tried 1.60 in drill mounts and had them break?

Nope. I've seen everything crack or break or chip, except Trivex.

[Michael Walach]

How about HI-VEX: hi-velocity impact resistant, COLTS Laboratories certified for all rimless and safety, refractive index 1.556, ABBE 46, specific gravity 1.25 g/cm^3. Try it you will like it

[sharpstick777]

I prefer 1.60 for drills, it finishes with a very clean edge, I have never chipped one, and the drill holes are clean and straight. We get more irregular drill holes on Trivex, the edges don't look as crisp, and patients are dissappointed that its just not that much thinner. It has the perfect amount of shine on the edge, not too much.

Most premium rimless lines, like Lindberg, recommend 1.60 over Trivex and Poly.

Poly has been cracking more and more the last few years. I order it extra thick to compensate, so it ends up thicker than 1.60.