Help me resolve a question about CR39 vs Poly

[Prentice Pro 9000]

Short story: Coworker order a two sets of lenses for a patient. One set Zeiss. One set Essilor. We try not to do this because it's better to keep stuff all in one house for each patient. The reason he did this is because he wanted both sets to be CR39. One was a comfort, and the other a Zeiss LightD.

So I thought about this... In a polarized lens I don't think ordering it in poly vs CR39 would really make a difference. My thinking is that, since less light is being allowed through the lens, the ABBE value becomes less important (since there's less light overall becoming dispersed as it passes through the lens). This, in my mind, is doubly so at lower prescriptions.

What do you think?

[DanLiv]

Totally agree. I put lots of people in poly sun who I have fit with CR-39, Trivex, or 1.60 in their clear eyewear. No problems. Cyls over 3D, or 1D or more prism I'll try to stick with the higher ABBE materials just to be safe.

This is orthogonal to your question, but for the same reasons I use simpler progressive designs in sunglasses too. I have many customers wearing fully customized top-tier lenses in clear, and inexpensive house brand digital or Ideal in sun. No problems. The light attenuation smoothes over all kinds of potential issues.

[Prentice Pro 9000]

Totally agree. I put lots of people in poly sun who I have fit with CR-39, Trivex, or 1.60 in their clear eyewear. No problems. Cyls over 3D, or 1D or more prism I'll try to stick with the higher ABBE materials just to be safe.

This is orthogonal to your question, but for the same reasons I use simpler progressive designs in sunglasses too. I have many customers wearing fully customized top-tier lenses in clear, and inexpensive house brand digital or Ideal in sun. No problems. The light attenuation smoothes over all kinds of potential issues.

to your 2nd point, I end up having to do this by default since the X design and MyStyle are not available in Polarized. Do you prefer any particular corridor lengths for your sun-wearers?

[NAICITPO]

Short story: Coworker order a two sets of lenses for a patient. One set Zeiss. One set Essilor. We try not to do this because it's better to keep stuff all in one house for each patient. The reason he did this is because he wanted both sets to be CR39. One was a comfort, and the other a Zeiss LightD.

So I thought about this... In a polarized lens I don't think ordering it in poly vs CR39 would really make a difference. My thinking is that, since less light is being allowed through the lens, the ABBE value becomes less important (since there's less light overall becoming dispersed as it passes through the lens). This, in my mind, is doubly so at lower prescriptions.

What do you think?

This is a great point, thanks for bringing it up. I typically don't see much aversion to polycarbonate anyway. I see opticians steering away from poly whenever there is something wrong with an order as a throw it all at the wall and see what sticks approach. But true aversion I think is much rarer than the poly haters put forward. I used to be one of them, put everyone in trivex. This article has helped me undestand why I may have been wrong.

https://www.2020mag.com/article/does...atients-vision



And as far as progressive lens designs to use for suns, I have become a fan of the little used Varilux Stylstic. Especially for the more wrapped sun frames. Customers seem to like it better than the previous options we have put them in.

[drk]

It's bias. I put everyone in poly and no complaints. It's fine.

And I doubt the chromatic aberration is reduced in a sunlens.

[Hayde]

The question should be 'difference for whom?' Many clear polys with a decent AR come back with abbes in mid or even high 30s. For strong scripts, sure it's worth bringing up so the Px can make an informed decision of the (unfortunately-oft exaggerated) risk of chromatic aberration. For the majority, there's no point in even bringing it up. I still prefer trivex for its relative superiority of aging condition, clear and especially shades more likely to endure exposure to the elements. Given the choice of poly to CR39--poly 99:1.

And I doubt the chromatic aberration is reduced in a sunlens.

I'm thinking the tint color could affect this widely...even more so with mirror.