When and why would you use 1.56 index. What is this index good for?
When and why would you use 1.56 index. What is this index good for?
all about lenses and their index:
http://www.opticiansfriend.com/lenses.html
It is a great mid index alternative for Rx ranges between +/-1.00D to +/-4.00D; also much cheaper than 1.53 Trivex and better optical characteristics than 1.59 Poly.
Abbe, AR coatings and scratch resistance are decent. The only downside is availability with Trans and polarized.
The only reason I was using it was in Sunsensors.....
Cheap thinner lenses.....
not good for logo...
It also tints really well.
Have I told you today how much I hate poly?
When you are too cheap to use 1.60, and scared of the poly monster. Even then, I've seen a lot of pricelists where this material in anything outside of SV and generic photochromics butts up against 1.67.
Beyond snark, I honestly don't see the purpose of this material, other than extensive backstock/existing manufacturing infrastructure providing a solution to a nonexistent problem, or at the very least a problem which has been solved by other materials. Thickness benefit over CR is negligible in most Rxs and offset by the brittle nature of the material/1.60 is thinner anyway/Trivex is more impact resistant. Let's face it: cost is the only good reason to use this material, and CR-39 trumps it there for a debatable gain in thickness.
Makes a great prank, though. Used some extra blanks in an office we acquired to pretend I dropped and shattered an rx. It got laughs.
1.56 is fairly brittle in my experience. It's alright, but be careful edging into nylor frames - chipsville
I'm sure I remember reading it's actually the most brittle plastic
There is a new 1.56 Hivex material that is more impact resistant. its NOT like the ormex 156 that was very chippy.
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