We order stock cr39 and poly SV lenses from a local stockhouse. They also have 1.56 on their menu (at approximately the same price as the other two) but I've never used it. We use Poly for most jobs and cr39 if the patient doesn't want the poly upgrade. For higher prescriptions we tend to surface with poly 1.0 or we use 1.67. I don't quite see the need for 1.56 or in what circumstances I would use it. Theoretically, we could replace our cr39 with 1.56 if there are any real advantages.
It's a good alternative to poly with superior acuity.
Originally Posted by ilanh
In my experience the 1.56 product is thinner and lighter than CR-39, not as thin or as safe as poly but better optics. I think it is also a bit on the brittle side and does not do particularly well in rimless. 1.60 would be a lot better, it has more tensile strength, is thinner, and has better ABBE values than the 1.56 or the 1.67. If 1.60 is not thin enough for our customers, we jump to Hoya 1.70.
I can't wait to see what the world looks like through normal lens materials, like Trivex.
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
Good Point.In my experience the 1.56 product is thinner and lighter than CR-39, not as thin or as safe as poly but better optics. I think it is also a bit on the brittle side and does not do particularly well in rimless. 1.60 would be a lot better, it has more tensile strength, is thinner, and has better ABBE values than the 1.56 or the 1.67.
I generally use 1.56 for plus prescriptions in full frames. It seems to balance weight, thickness, and higher abbe better than does poly. I try to avoid poly for most things. +3.00 to +5.00 works well with this index (Spectralite).
Don't let a billy goat guard your cabbage patch.
I mostly use EvoClear from Armorlite in the +/- 5 range.
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
The advantage is limited. It's actually more brittle and easier to flake than CR-39. I even see full metal frames w/1.56 that are flaked.
I use it for higher plus in medicaid (stock only)
AR doesn't adhere well to it. SCR doesn't adhere well either
It comes in high cyl from ELOA. That's an advantage for medicaid jobs that would otherwise need to be surfaced or use Resolution at a much higher price.
I also use it for readers over 3.00 or so. I never buy it surfaced because it it too expensive. No benefit for a surfaced lens, except for a rare instance where you need an extra-thick blank for 10D of prism.
I've never used it until now. Just had someone give me about 1000 pairs for the charity work.
I used to use it exclusively for my higher RX tint jobs!
trivex, trivex, trivex.
Let the refining and improving of your own life keep you so busy that you have little time to criticize others. -H. Jackson Brown Jr.
If the only tool you have is a hammer you will approach every problem as though it were a nail
How does it tints/neutralises??
We use 1.56 as an inexpensive alternative to jobs that fall over the -4 range. Never had a problem with it flaking or with coatings peeling. 99% of the time we sell it with an AR coat but I've tinted a couple in the last week or 2 and they turned out nicely.
I've only had a chance to try 3 or 4 pairs of the ones given to us, but it seems OK. I don't know why more of it isn't used, it seems to be a good material, so far.
We also do a lot of 3rd party jobs. When the government says High Index they mean 1.56. Doesn't matter if you're a plus 10 or a minus 10
I was always under the impression that 1.56 was good UP TO 4.00 diopters not OVER 4.00 diopters.
Regards,
Golfnorth
I hope you're totally wrong. :)
"When do you use 1.56?"
Never!!!!
:D:cheers:;):cheers::D
Try to tell the government someone should be bumped into a 1.6.
THE CANADIAN GOVERNMENT!
Well it's my understanding that with an Rx over 4.00 diopters a 1.6 or Poly will control the thickness better.
Regards,
Golfnorth
I'll refrain from making a sex joke at this moment but just barely.
Ahhhhh......the Blasted Maple Leafs and the Mounties can............!
;):cheers::bbg::cheers::)
i was wondering if someone could give me a gudeline of approximate powers that should be used for plastic of different refractive indices?
ie,
1.5 ... power range +3 to -4
1.56
1.6
1.67
1.7
thanks!
In my humble opinion you wouldn't be needing to ask that question if you had a licensed optician on staff.
Why on average don't OD's, and you specifically, recognize the value of a licensed optician?
Regards,
Golfnorth
Good swing. You have hit the nail squarely on the head.
I know a lot of opticians that make bad lens choices.
Or their customers do not want to pay for the right choices!?
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
Bookmarks