Lens thickness question

Hi, I'm getting ready to buy a backup pair of glasses, and they'll be
the first pair of glasses I'll have been able to really research, since
I've finally learned my lesson (+my prescription is settling down...
only changing by a decrease of -0.25 spherical power diopter every 2
years, and an increase of -0.25 cylinder power in one eye (OD) over the
last 4 years.

Anyways, I'm curious both about lens thickness and optics. I know that
the frame matters a lot to thickness - and my current frames are the
tiniest ones I've had yet (I'm 21, on my 6th pair of glasses, and I've
noticed every pair I get gets smaller). I also got my first contact
lenses this time! But I don't really like wearing them (Ciba
O2Optix)... My eyes get tired more easily, I get more headaches (partly
since unlike glasses I can't just take them off to read and use the
computer), etc... Anyways, my current frames are these:
http://framesdirect.com/framesfp/Candies-tapfm/r.html (size
46-18-130). They were bought at Pearle Vision and I have Seiko 1.60
index aspheric lenses that were stock and stock AR coated. I'm very
satisfied with the thickness and optics - though I don't care for the
greenish AR (before I had Zeiss Gold ET on a non-aspheric, unnamed,
1.60 index). Pearle Vision did have to redo them *three* times until I
got a pair of lenses that didn't have tiny scratches in the coating!!!

I LOVED the Zeiss Gold ET but needed glasses-in-an-hour (and that meant
stock lenses) this time (my old ones literally fell apart when cleaning
them one day - they were a cheap plastic frame with tons of tiny cracks
in it)

Historically, before my last pair I had always had what my parents
bought for me - uncoated polycarbonate. The stuff gave me terrible
headaches from glare and the chromatic aberration really bothered me.
But I was a kid and teenager - I didn't know there WERE any other type
of glasses, and the possibility of different lens materials being
optically better (I was TOLD as a kid by opticians that polycarbonate
was "far better than plastic") and coatings was never presented to me.
I was told by a good friend of mine when complaining about how I hated
glasses that I needed AR coating and better lenses - both he and his
(then ten, now twelve year old) daughter had high-index AR coated
lenses for the same problems I had and both said they made all the
difference in the world - and they do!

Anyways, sorry for all that but hopefully it helps you provide me
recommendations for the best cost for money for me in a backup pair of
glasses. Are Costco's glasses decent? Anywhere else cheap? In a frame
the size of the one I'm wearing now - what will the edge thickness of
the different materials on the market? How would CR-39 look in my
prescription with my frame size - these 1.60's are SO thin in this
frame, I'm thinking CR-39 might not be TOO bad for backup glasses. How
would they compare optically? What are the best (non-glass) optics I
can get? What is cheap and still great for backup glasses (which I'll
probably be wearing quite often - they won't be sit-in-a-drawer backup,
they'll probably be a slightly different style and color so I can match
outfits better than being stuck with one pair)

Thanks for any recommendations you can make - I've learned my lesson
that lens and coating choices can change how I see my world -
literally. Headaches as a kid are gone. Hate for wearing my glasses -
70% gone. (Of course, part of that is finally getting some nice tiny
frames vs. the huge things I used to wear (at the encouragement of the
optician!) But the AR, in addition to getting rid of glare also makes
me feel better about wearing them). That's why I want to get some
professional (and experienced amateur ) opinions before I go
shopping for this pair!

Thanks so much in advance,

Mark

 

OOPS, I forgot my prescription *blushes*

It's:

OD -3.00 -0.50 170
OS -3.00 -0.75 011

Thanks again in advance!

Mark

 

Stores like Costco and Wal-Mart/Sams carry a large variety of lenses, some
very good and some mediocre. Unlike chains such as Lenscrafters and Pearle,
you can find out exactly what brand and model of lens you are getting from
Costco and Wal-Mart/Sams.

For your Rx, I would recommend that you consider Sola lenses made from
Spectralite material. This is a light weight and very high quality (high
abbe value) lens that is about 1.53 index, which should be fine for your Rx
and small frame. I believe that Wal-Mart sold these at one time, but not
sure if they still do.

You are correct to stay away from polycarbonate, unless you need safety
glasses, in which case Trivex would be better (Hoya Phoenix or Younger
Image).

 

I don't need safety glasses and I know from past experience that I
can't stand polycarbonate and non-AR lenses. I'm curious how CR-39
would be - is my prescription too strong to get reasonable thin CR-39
lenses. My current Seiko's are quite nice - what would I be looking at
for CR-39 thickness compared to these? Twice?

Thanks,

Mark

 

CR-39 (1.50 index) would definitely be thicker and heaver than a higher
index lens. Sola Spectralite (1.53) would be a definite improvement in
thickness and weight, with almost no loss in quality.

The edge thickness is what would be noticeable in a minus lens like yours.
How much it would be noticeable depends on the frame size and configuration.
Most people with your Rx would probably use something a little thinner and
lighter than CR-39.

 

Thanks! That's what I was wondering as CR-39 is so much cheaper and
said to be good.

I'm very happy with the 1.60 aspheric Seiko lenses - there's zero
noticeable edge thickness (the lens is at most a mm thicker than the
frame at the sides and since it's balanced half to the front, half to
the back, you can't tell from any distance over a few inches that the
lens is thicker than the frame). I like that. It's not really worth
giving that up to save a few dollars. Though is CR-39 really any
HEAVIER? I've been under the impression that the low specific gravity
made the product sill LIGHTER. My current glasses are essentially
weightless (I can't feel the weight), the first pair (including ones
with another 1.60 material) I can say that about.

Isn't Spectralite MORE expensive than 1.60? If I'm optically happy with
the 1.60's (which I very much am especially these new tiny aspheric
ones- it's just the polycarbonate I couldn't stand) what would be the
reason to spend more on Spectralite? I'm kinda looking CHEAPER
suggestions that still meet my needs But thanks very much for your
info!

Sincerely,

Mark

 

Thank you VERY much That's exactly what I needed to hear! Yeah,
twice as thick and I'd actually see the lenses and all, no thanks!
Question - why then would anyone buy CR-39 compared to at the least,
materials like Trivex? I mean other than cost, why would someone put up
with such thick lenses?

Are there any really great materials I should be looking at? And any
suggestions on a good commonly available AR that's not green? (boy was
Gold ET tough to get and expensive but I loved it)

 

To be honest, I just choose the cheapest lenses possible. The most
important thing is that you are able to see. Minus three is not thick
at all, so just go for normal lenses, whatever the cheapest is. What
did glasses wearers do before all of these types of lenses? Well,
that's a European standpoint. You in the States are so capitalistic.

 

That's why most Europeans sound sort of nasal.
Those heavy glasses have squashed their noses... -

-Quick

 

CR-39 is probably more expensive in Europe than Spectralite is in the US
(especially at Wal-Mart).