Glass glasses and hot coatings

I have been using antireflection coated plastic lenses now for about 18
months. For a while, I was surprised by how well they were surviving
cleaning. Now, scratches and fuzziness is beginning to show up.

How easy is it to get real glass lens spectacles these days? It seems the
plastic is still being marketed more strongly than glass. Is it difficult to
to get hard coatings such as quarter-wave (or higher performance designs)
magnesium fluoride deposited upon hot glass lenses? How do I go about doing
so without getting supercilious lectures on why the customer is totally
ignorant about such matters?

If I want computer glasses, how do I go about getting my distance/reading
prescription modified according my specifications, again without having a
nanny OD or ophthalmologist telling me that they know better. In my case I
would want about a 1.75D addition to my distance prescription with a 1.25D
or 1.50D bifocal add.

I know that one argument for plastic is that it will make for lighter
spectacles. In my case, after double cataract surgery, the thickness of
external corrective lenses can be greatly reduced from what used to be
necessary.

Bill

Repeating Rifle wrote:

> I have been using antireflection coated plastic lenses now for about 18
> months. For a while, I was surprised by how well they were surviving
> cleaning. Now, scratches and fuzziness is beginning to show up.

18 mos isn't bad, and the coatings are getting better (and more
expensive) all the time. There are lots of high quality coatings to
choose from these days.
>
> How easy is it to get real glass lens spectacles these days? It seems the
> plastic is still being marketed more strongly than glass.

Not yet on the black market. No problem, if you don't mind the extra
weight or your nose and the additional safety risk (they will be
hardened, if purchased in the USA, but can still break into sharp, eye
cutting projectiles if hit hard enough.


Is it difficult to
> to get hard coatings such as quarter-wave (or higher performance designs)
> magnesium fluoride deposited upon hot glass lenses? How do I go about doing
> so without getting supercilious lectures on why the customer is totally
> ignorant about such matters?

Glass is the most scratch resistant lens material on the planet, and the
AR coatings that go on them are equally tough. No problem.

>
> If I want computer glasses, how do I go about getting my distance/reading
> prescription modified according my specifications, again without having a
> nanny OD or ophthalmologist telling me that they know better. In my case I
> would want about a 1.75D addition to my distance prescription with a 1.25D
> or 1.50D bifocal add.

OK if you like your monitor "in your face". I prefer a +1.25 add for
the upper part, so I can sit farther back from the monitor, a strong
personal preference. Plus you get greater depth of focus. And why so
strong in the lower? Unless you're less than 20/20 best corrected, you
may regret the narrow depth of focus there too.

>
> I know that one argument for plastic is that it will make for lighter
> spectacles. In my case, after double cataract surgery, the thickness of
> external corrective lenses can be greatly reduced from what used to be
> necessary.

True, especially for computer glasses (I assume you WILL NOT be using
these to run a lathe or some such activity?)>

w.stacy, o.d.

William Stacy wrote:
<snip>
> No problem, if you don't mind the extra
> weight or your nose
> w.stacy, o.d.

Funny enough, the people who discouraged me from getting glass lenses
used this as their primary argument. Weight. For the first few days I
*did* notice the difference, but honestly, after wearing the glasses
for ~ 2 mo. or so, I've gotten accustomed to it (and this is with an Rx
in the mid teens ... should be even easier to do with a lower Rx). But
anyway ...

(E-Mail Removed) wrote:
> William Stacy wrote:
> <snip>
>> No problem, if you don't mind the extra
>> weight or your nose
>> w.stacy, o.d.
>
> Funny enough, the people who discouraged me from getting
> glass lenses used this as their primary argument.
> Weight. For the first few days I *did* notice the
> difference, but honestly, after wearing the glasses for ~
> 2 mo. or so, I've gotten accustomed to it (and this is
> with an Rx in the mid teens ... should be even easier to
> do with a lower Rx). But anyway ...

I wore glass (non-Rx) sunglasses for many years. I was on
the road a lot. Polarized, darkest neutral grey with a double
gradient mirror. Ray Ban used to make a decent one until
the hardening law in ('64?). Somewhat more recently Nikon
made very excellent sunglasses (both lens and frame) with
glass lenses and all the coatings and stuff inside the sandwich.

The weight became very noticeable with all day wear in
hot humid environments (golf). Once my face got oily and
sweaty I couldn't keep them from sliding off my nose.

I recently switched to Rudy Project sunglasses because of
that and becoming a bit more safety concious. They're supposed
to have really good optical characteristics? The glass lenses
were significantly better. I've stayed with the plastic for the other
reasons.

-Quick

Than you for a very informative reply

On 7/17/05 9:45 PM, in article
MtGCe.4376$_%(E-Mail Removed), "William Stacy"
<(E-Mail Removed)> wrote:

<snip a bit>

>> If I want computer glasses, how do I go about getting my distance/reading
>> prescription modified according my specifications, again without having a
>> nanny OD or ophthalmologist telling me that they know better. In my case I
>> would want about a 1.75D addition to my distance prescription with a 1.25D
>> or 1.50D bifocal add.
>
> OK if you like your monitor "in your face". I prefer a +1.25 add for
> the upper part, so I can sit farther back from the monitor, a strong
> personal preference. Plus you get greater depth of focus. And why so
> strong in the lower? Unless you're less than 20/20 best corrected, you
> may regret the narrow depth of focus there too.

With my monitor at a distance I liked, I measured distance to it at about 57
or 58 cm. If my distance correction is optimum and accurate, then 1.75D is
just about right to move the screen to infinity.

Often, while I am at my computer, I want to read smaller print or read
instructions in dimmer than usual light. Seldom am I actually typing copy
from a manuscript or a book. I like the extra bit of magnification.

With intraocular implants, I get no accommodation anyway.
>
>>
>> I know that one argument for plastic is that it will make for lighter
>> spectacles. In my case, after double cataract surgery, the thickness of
>> external corrective lenses can be greatly reduced from what used to be
>> necessary.
>
> True, especially for computer glasses (I assume you WILL NOT be using
> these to run a lathe or some such activity?)>

Moreover, for my computer, I will probably get frames with somewhat smaller
area than I would for general purpose wear.

I must admit that I have been tempted to get the combination lathe, mill,
and drill press made in China as sold by Harbor Freight. So far, I have
resisted that impulse. I would probably get polycarbonate (Lexan) safety
goggles if I ever were to yield to that temptation.

Bill

Quick wrote:
> (E-Mail Removed) wrote:


> The weight became very noticeable with all day wear in
> hot humid environments (golf). Once my face got oily and
> sweaty I couldn't keep them from sliding off my nose.

Although I don't play golf, the whether in Toronto has definitely been
hot and humid lately. I don't think I'll be going out for an extended
period of time though. But yeah, I could see how that would be a
problem. Glass lenses fit my lifestyle quite well. I still think what
everyone was telling me was an exaggerated version of the truth.
Perhaps in certain circumstances they are noticeably heavy, but in most
of the situations I encounter on a daily basis, they are perfectly
fine.