Re: Eyeglasses (was Re: Who has done more damage to RCM)

In article <497abd77$0$25462$607ed4bc@xxxxxx>,
"Ed Huntress" <huntres23@xxxxxxxxxxxxx> wrote:

"Joseph Gwinn" <joegwinn@xxxxxxxxxxx> wrote in message
news:joegwinn-AD3CFE.18343523012009@xxxxxxxxxxxxxxxxxxxx
In article <497a32bc$0$25428$607ed4bc@xxxxxx>,
"Ed Huntress" <huntres23@xxxxxxxxxxxxx> wrote:

"Joseph Gwinn" <joegwinn@xxxxxxxxxxx> wrote in message
news:joegwinn-D389FC.14122618012009@xxxxxxxxxxxxxxxxxxxx
In article <4973645c$0$20304$607ed4bc@xxxxxx>,

Hi, Joe. I promised I'd report back on my new glasses.

These are Varilux Physio 360 progressives, anti-reflection coating,
polycarbonate, two-year warranty. Retail price on the lenses is $619.
Don't
try this without good insurance. <g> The Physio 360 supposedly is about
as
good as it gets for people with typical prescriptions, which mine is.

Anyway, they're pretty impressive -- they sharpen my distance vision and
increase my depth of field on the short end (upper lenses) with no
noticeable distortion on the sides. I can even get a sharp read on the
front
sights of my pistols without losing the distance sharpness. That's
something
I didn't expect. Reading (lower lenses) is great, but with slight
distortion
at the sides. It's not bothersome, however.

Good to hear.


The problem is with reading the computer screen. That distance falls
right
between the distance- and reading-lens ranges, in the transition range of
the progression, and, vertically, it's too narrow to be comfortable for
extended periods. And the side distortion there is enough to notice.
Overall, the window of sharpness is a bit small and it's annoying after a
while.

One of my coworkers, a programmer, has progressives, and you see him at
his computer for hours holding his head at an awkward angle. It would
kill my neck for sure.

I don't think I'd be able to tolerate that. I'm wearing some low-power
readers right now and they're better than the progressives for working at
the computer. I'd hoped I wouldn't have to change glasses any more, but it
looks like I'll still need the readers for working long periods at the
computer.

Still, I can't complain. That's a minor PITA compared to having to change
glasses to read every soup-can label.

I wouldn't wear these in the shop, either. My shop glasses turn me into an
instant geek. <g> I wear low-power readers with plastic frames to hold my
B&L swing-away loupe (they're lousy on wireframes), and I usually have my
magnifying visor on at the same time, swung up over my head. My wife can't
stop laughing when she sees me fully equipped. d8-)

The only missing fashion article is a half-mask respirator to handle the
oil mist.

It makes me look like a preying mantis.


A good combination would be computer foucus above (20" or so) and
reading focus below (14"), with progress between. I'll probably get
such glasses, but bifocal.

They'd be a good idea. Maybe I'll try that sometime in the future.



Given all the compromises with progressives, it looks like I'd give up
too
much at the close and distant ends if I had a wider range in the middle.
So
I'm stuck with low-power readers for extended work at the computer. I
think.
What I've noticed is that I'm adapting to them even at the computer, and
I
just spent an hour typing without realizing I was wearing the
progressives.
So maybe it's an adjustment that I'll make naturally.

All in all, I'm pleased. I'm especially pleased that I've been able to
walk
all around town, and up and down stairs, without falling down. d8-)

If they aren't making you sick, you'll likely adjust.

The only time I had a prescription fail was when the lenses were for
very different focus distances. I could feel my eyes racking back and
forth, trying to find a suitable compromise. Got a new, correct,
prescription. The problem was that eyeglasses are normally fitted one
eye at a time, which rarely fails. Now, I always tell them that they
have to do the final adjustment with both eyes open, especially for
close-work glasses prescriptions.

I'll try to remember that. This is the first pair of prescription glasses
I've needed in 30 years, because my only issue was a little farsightedness
that was easy to deal with using magnifying readers. After my laser surgery
late last year, I was feeling some eyestrain at longer distances as well.



It's amazing what people (well, sophmores) can adjust to. There were
some scientific experiments where the subjects wore glasses that turned
everything upsidedown. After a few days, no problem. Less drama on
return to normal.

I remember that research. In fact, they had done that at Michigan State a
few years before I was a student there -- probably duplicating the original
research. Very interesting.

BTW, I got some info on the polycarbonates from Varilux. The thing they push
with their expensive lenses is their laser-controlled feedback system to map
the back side of the lens in grinding, and some other technology I didn't
dig into, but they also have a patented cool-grinding technique for use with
polycarbonate. Apparently the material is very prone to distortion if you
grind them the same way that they grind CR-39.

I didn't question this and I don't know how accurate that is, but it was
interesting.

I thought that CR39 was cast to final optical shape of the blank at the
factory, and then subsequently edge-ground to fit the frames by the
optician. This allows all the fancy, expensive precision optical-level
grinding to be done to the steel mold, which then makes many thousands
of lenses.

I never looked into polycarbonate, but I really doubt that they can
afford to grind each spectacle lens individually. I bet the lenses are
formed (hot-pressed?) in accurate steel molds as well.

Maybe the cool grinding is so the mold won't distort while being ground
to shape. This is widely done when making steel items to 0.0001" (2.54
micron) accuracy, and a wavelength of red light is about 0.6 microns.


Joe Gwinn
.

Relevant Pages

  • Re: Eyeglasses (was Re: Who has done more damage to RCM)
    ... I promised I'd report back on my new glasses. ... Retail price on the lenses is $619. ... One of my coworkers, a programmer, has progressives, and you see him at ... readers right now and they're better than the progressives for working at ...
    (rec.crafts.metalworking)
  • Re: Vision Correction and Golf (longish)
    ... distortion at the edges of the lenses than with progressives. ... the same place with glasses as without glasses. ... I heaved the regular lenses and had my guy put a set of progressives into ... dominant eye is my right). ...
    (rec.sport.golf)
  • Re: Progressive lenses such as Varilux
    ... That could be scratched up lenses, scratched up hard coat (used on ... Glasses that have an anti-reflective coating need to be treated the ... same way you would treat an expensive camera lens -- i.e., ... your money on progressives. ...
    (sci.med.vision)
  • Re: presbyopia
    ... LENS" was registered by Iovision Inc. in 1989 for intraocular lenses, ... went back to single-vision glasses. ... My first bifocals were the progressive kind. ... So I had to keep the old progressives ...
    (alt.usage.english)
  • Re: Reasonable prices for great glasses
    ... D-28 bifocals would add around $100 to the cost over single ... Progressives would add about $200 to the cost over single ... They are the thinnest and most premium lenses ... This is especially true if they were their glasses all ...
    (sci.med.vision)