
A Look at Eyeglass Lens Materials (2012) - walterbell
https://www.eyecarebusiness.com/issues/2012/august-2012/a-look-at-lens-materials
======
ScottBurson
A blog post of mine explains why I switched to CR-39 for computer work:
[http://scottlburson2.blogspot.com/2016/01/lcd-backlights-
and...](http://scottlburson2.blogspot.com/2016/01/lcd-backlights-and-eyeglass-
lenses.html)

I've learned since then that RGB LED backlights, specifically, are not
actually all that common, as other wide-gamut technologies become more common
-- GB-r and RB-g, which use two colors of LEDs and a phosphor for the third
color; and quantum dots. This doesn't change the outcome, though, as these
technologies also produce spectra with a wider spacing between red and green
peaks than the old CCFLs or WLED.

I wear my CR-39 glasses all the time (except for driving or biking) and am
quite fond of them.

------
city41
I made glasses at LensCrafters throughout college (super enjoyable job btw!).
My main takeaway was to avoid polycarbonate lenses. People returned them often
due to headaches, and I experienced headaches myself as my safety glasses were
required to be polycarbonate. Polycarbonate can be a decent compromise in some
situations as the lenses will be thinner than equivalent plastic lenses.

~~~
walterbell
What do you think of Trivex / Tribrid?

~~~
CalChris
Tribrid is newish (2013) and targeted for stronger prescriptions in the
+/-3.00 to +/-7.00 diopters range. It's a little heavier (1.23 vs 1.11) than
Trivex and slightly worse Abbe (41 vs 44) but has refractive index of 1.60 vs
1.53.

[http://www.visionmonday.com/article/ppg-launches-tribrid-
len...](http://www.visionmonday.com/article/ppg-launches-tribrid-lenses-in-
north-america/)

I want a tool where I can find out if a lens for my prescription is lighter in
one material vs another. Trivex is lighter than Tribrid but has a lower RI.
I'm at -3.

~~~
walterbell
This one calculates center & edge thickness:
[http://64.50.176.246/tools/thickness.php](http://64.50.176.246/tools/thickness.php)

This one claims to calculate weight: [http://www.glassfab.com/tools/weight-
calculators/weight-of-a...](http://www.glassfab.com/tools/weight-
calculators/weight-of-a-lens/)

------
amitp
That was one of the five sites I found for eyeglass materials. These are the
others:

\- [http://www.allaboutvision.com/lenses/how-to-
choose.htm](http://www.allaboutvision.com/lenses/how-to-choose.htm)

\-
[https://web.archive.org/web/20090815102701/http://www.hbutz....](https://web.archive.org/web/20090815102701/http://www.hbutz.com:80/wwwboard/messages/201.html)
(table at end)

\-
[https://en.wikipedia.org/wiki/Corrective_lens#Ophthalmic_mat...](https://en.wikipedia.org/wiki/Corrective_lens#Ophthalmic_material_property_tables)

\-
[https://web.archive.org/web/20160322110111/http://www.optica...](https://web.archive.org/web/20160322110111/http://www.opticampus.com/tools/materials.php)

Trivex is impact resistant and lighter but it's also a little thicker than
some of the high index materials so the weight ends up being the same. MR-8
was the one I hadn't heard of and was most curious about.

[https://www.reddit.com/r/AskReddit/comments/4v3ts4/what_was_...](https://www.reddit.com/r/AskReddit/comments/4v3ts4/what_was_your_why_didnt_i_start_doing_this_sooner/d5vncsk/?context=1)
has some notes about scratch resistance

With high index lenses, the chromatic aberration (low "abbe number") was
annoying me (see ScottBurson's post), especially on a wide screen monitor. I
ended up getting lenses made of _glass_. But these aren't so great outdoors
because you don't want shattered glass in your eye.

I ended up getting glass for use at home at the computer and MR-8 for the rest
of the time (hiking, driving). For the computer lenses, I got a slightly lower
prescription (-4 instead of -5) and they're a lot more comfortable for reading
(people may find these useful after the age of 40). I think next time I'll go
for CR-39 instead of glass, as the glass lenses are rather heavy.

------
gm-conspiracy
Does anybody know where to order high-index lenses (1.74) in the US?

I can get them from China for about $150.

~~~
walterbell
Seiko 1.74 lens + premium hydrophobic AR for $140,
[https://www.39dollarglasses.com/product_info/use_your_own_fr...](https://www.39dollarglasses.com/product_info/use_your_own_frame.html)

Essilor 1.74 + Crizal Avance for $230 at
[http://www.replacementlensexpress.com/single-vision-clear-
ul...](http://www.replacementlensexpress.com/single-vision-clear-ultra-high-
index-1.74-lenses.html)

Jins has frame + lens (up to 1.67) for $120 flat price,
[https://www.jins.com/us/our-commitments](https://www.jins.com/us/our-
commitments)

MR-8 1.60 has better optical quality (higher Abbe, less chromatic aberration)
than 1.67 or 1.74, even though it's cheaper:
[http://ophthalmiclenses.blogspot.com/2012/05/all-about-mr-
se...](http://ophthalmiclenses.blogspot.com/2012/05/all-about-mr-
seriesmr-8-mr-7-mr-10-mr.html)

~~~
troydavis
I’ve had 39 Dollar Glasses’ 1.74 index for 2 years and am very happy.

Before 39DG, I ordered Zenni’s 1.74 (in almost identical lens dimensions and
effective lens PD). The lenses on Zenni’s glasses were much thicker than any
I’d previously had, and than 39DG’s subsequent pair. I don’t know whether
Zenni mis-ground them or what. I’ll gladly reorder from 39DG though.

