Re: polycarb vs 1.67 for weak prescription

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Re: polycarb vs 1.67 for weak prescription

Mark A

24 Jun 2006 01:00

> <snip>
>
> I have found that 1.67 performs better in a rimless frame, however the
> lower abbe value of 1.67 versus poly may be an issue.
>
> <snip>

I believe that 1.67 has an abbe value of 32 and polycarb has a abbe value of
30 (the higher the less chromatic aberration).
Here is a link from an Essilor (parent of Varilux) site in UK:
http://www.essilor.co.uk/lensinfo/pdfs/Stylis%20Brochure.pdf
(see page 6 of the doc).

Anon E. Muss

24 Jun 2006 00:10

>Ok, Doc is really advising against CR-30 and recommends
>polycarb, or as an alternative 1.67, 'cause I'm getting drill
>mounts. Air Titanium rimless.

For drill-mounted frames, my preference for materials is this, from
best to worst: TRIVEX, 1.67, polycarb, CR-39, other mid-index
plastic.

>O.D. +1.25 sph add +2.25
>O.S. +0.75 -0.25 add +2.25
[quoted text clipped - 8 lines]
>So...
>I don't expect the difference in thinness to be measurable.

It isn't in that prescription.

>I don't expect the difference in weight to be noticeable.

It won't.

>Is there any possibility I could see any material caused abberations
>with either (I'm very sensitive to that sort ofthing)?

Yes, but that possibility is low with that small of a precription.

I second Dr. Leukoma's opinion. For a rimless frame, I would ask if
you could be prescribed a progressive you can get in TRANSITIONS V
TRIVEX such as Hoya's Summit ECP. Essilor will not/cannot apply
Crizal Alize to a TRIVEX lens, but I-Coat's Vivix Stainless and Hoya's
high-end A/R coat (Super HiVision?) are just as good IMHO.

I would be surprised if you are one of the rare birds that find a
noticable negative difference being prescribed a Hoya Summit ECP
versus a Varilux Physio 360.

>Would there be any difference with the transitions performance?

I have found all of the TRANSITIONS V materials to perform about the
same. Make sure you are aware of the pros/cons of TRANSITIONS lenses.

>Price difference is about 10% of total so not a factor if there is any
>advantage to the 1.67

That is a low price difference.

I have found that 1.67 performs better in a rimless frame, however the
lower abbe value of 1.67 versus poly may be an issue. 1.67 performs
better as in less risk of the spider cracks at the drill points that
is not uncommon after time with polycarbonate.

However, both poly and 1.67 have lower abbe values than TRIVEX or
CR-39.

Quick

23 Jun 2006 05:28

Ok, Doc is really advising against CR-30 and recommends
polycarb, or as an alternative 1.67, 'cause I'm getting drill
mounts. Air Titanium rimless.

O.D. +1.25 sph add +2.25
O.S. +0.75 -0.25 add +2.25

Physio 360
Crizal Alize with Clear Guard (gold)
Transitions (grey)

Yea, I know, I don't need the 360... it's only $20 more.
I don't play Jai Lai

So...
I don't expect the difference in thinness to be measurable.
I don't expect the difference in weight to be noticeable.

Is there any possibility I could see any material caused
abberations with either (I'm very sensitive to that sort of
thing)?
Would there be any difference with the transitions
performance?

Price difference is about 10% of total so not a factor
if there is any advantage to the 1.67

-Quick

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