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Medical Forum / General / Vision / December 2006

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What does "Pl" mean?

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John Richards - 14 Nov 2006 22:48 GMT
I just had an eye exam (first in eight years). When I got home
I looked at the prescription and it had "Pl" under Sphere for
one eye. That same eye was -0.75 eight years ago.
Anyone know what the Pl notation means?

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John Richards

Glenn - USAEyes.org - 14 Nov 2006 22:59 GMT
Pl is short for "plano", which means no refractive error. The light
entering that eye is properly focused at the retina.

Glenn Hagele
Executive Director
USAEyes.org
Patient Advocacy Surgeon Certification

"Consider and Choose With Confidence"

Email to glenn dot hagele at usaeyes dot org

http://www.USAEyes.org
http://www.ComplicatedEyes.org

I am not a doctor.

Copyright 2006
All Rights Reserved
John Richards - 14 Nov 2006 23:24 GMT
Thanks. Seems like it would be more comprehensible if the
optometrist would simply write 0.00 for the sphere parameter.

Signature

John Richards

> Pl is short for "plano", which means no refractive error. The light
> entering that eye is properly focused at the retina.
Mike Tyner - 15 Nov 2006 00:31 GMT
> Thanks. Seems like it would be more comprehensible if the optometrist
> would simply write 0.00 for the sphere parameter.

IIRC it's because zeroes can look like sixes, and "pl" is easier to write.

-MT
Glenn - USAEyes.org - 15 Nov 2006 02:24 GMT
Keeping things consistent would be better, but if you consider plus
cylinder and minus cylinder you will understand that the industry
seems quite content with confusion.

Glenn Hagele
Executive Director
USAEyes.org
Patient Advocacy Surgeon Certification

"Consider and Choose With Confidence"

Email to glenn dot hagele at usaeyes dot org

http://www.USAEyes.org
http://www.ComplicatedEyes.org

I am not a doctor.

Copyright 2006
All Rights Reserved
William Stacy, O.D. - 15 Nov 2006 03:09 GMT
Not quite. Pl under the sphere means the spherical component of the
spectacle Rx is 0.00.  I does NOT mean that there is no refractive
error.  There can be cylinder, prism, and there can even be a spherical
component to the refractive error which is being adjusted to zero in the
spectacle Rx for one reason or another (can be many reasons).

w.stacy, o.d.

> Pl is short for "plano", which means no refractive error. The light
> entering that eye is properly focused at the retina.
>
> Glenn Hagele
Norayn - 15 Nov 2006 19:16 GMT
I am looking for a source that can provide Glass Lenses in an Executive
Bifocal.

Is anyone still making this lens??

Thank you, Stacye M.
Robert Martellaro - 15 Nov 2006 20:55 GMT
>I am looking for a source that can provide Glass Lenses in an Executive
>Bifocal.
>
>Is anyone still making this lens??
>
>Thank you, Stacye M.

Stacye,

Not in the United States. It is available in plastic, and you can still get
ST35's in crown glass.

Regards,
Robert Martellaro
~~~~~~~~~~~~~~~~~~
Optician/Owner
Roberts Optical
Wauwatosa Wi.
~~~~~~~~~~~~~~~~~~
"An expert is a person who has made all the mistakes that can be made in a very narrow field."
 - Niels Bohr
William Stacy - 15 Nov 2006 22:43 GMT
>Not in the United States. It is available in plastic, and you can still get
>ST35's in crown glass.
>
>  

The passing of an era. The exec glass was a very good lens, an optically
perfect version of the original bifocal invented by Ben Franklin.  
American Optical made the best quality Exec (aka e-line, no jump,
Franklin) in glass and the plastic versions never seemed to me to have
the quality as the original.  As the years go by, the line gets more
smeared and there is more and more prism at the line (not predictable in
amount).  I don't know what the difference in manufacturing technique is
(I never could figure out exactly how they ground those front surfaces),
but I'd bet they are using old glass molds to form the plastic versions,
and they are deteriorating.

We used to make good frames, too...

w.stacy, o.d.
David Combs - 04 Dec 2006 17:02 GMT
>>I am looking for a source that can provide Glass Lenses in an Executive
>>Bifocal.
>>
>>Is anyone still making this lens??

Unbelievable!

First it was executive trifocals they stopped making (glass).

And now BI-focals?

Any idea WHY?

And, don't Americans care (any more) about decent-VISION
through their eyeglasses?

Or is it simply greedy CEOs wanting every possible extra
penny in EPS, since (often?) many tens-of-millions of dollars
payout is boosted by that?

>>Thank you, Stacye M.
>
>Stacye,
>
>Not in the United States.

QUESTION:
Where then can you get them from?

It is available in plastic, and you can still get
>ST35's in crown glass.

QUESTION:
And what are *they*?

Thanks,

David
William Stacy, O.D. - 05 Dec 2006 03:55 GMT
Not enough demand.  Probably because they aren't teaching ophthalmic
optics like they used to.  New people think the lines are "ugly".
They are programmed to "sell" progressives, and that if a lens is more
expensive, it "must" be better.

>>>I am looking for a source that can provide Glass Lenses in an Executive
>>>Bifocal.
[quoted text clipped - 8 lines]
>
> Any idea WHY?
David Combs - 09 Dec 2006 02:46 GMT
Subject: What's a "flat-top" lens-shape/geometry?  (Was: Glass Executive Bifocal)

I was told (just yesterday) by a glasses-manufacturer I was
briefly talked to that I should look into "flat tops" (no,
not navy ships!).

For bifocals and trifocals, how do these flat-tops differ?

Pros, Cons?

(he said they came in glass too)

Thanks,

David
William Stacy, O.D. - 09 Dec 2006 19:05 GMT
It is a D shaped (with the curved side downward) that is commonly used,
available in 22, 28, 35, 45 mm widths, although I don't think 45 is
avail in glass.  The trifocal version is like the D but with two
straight lines, parallel to each other in the D instead of one, in
various separations (between the two lines, where the power is about
half the add of the lower part) from 7 mm to 14 mm. Again, less
availability in glass than plastic (I've only seen 7x28 and 8x35 in
glass.  My favorite is the E-D trifocal, which has an exec upper line
and a D style "bifocal" seg set 8 mm down from that line.  They used to
have an F-D with a 12 mm separation.  A great lens, but my own usage of
it in my practice was not enough to keep Sola making it.  Alas.

w.stacy, o.d.

> Subject: What's a "flat-top" lens-shape/geometry?  (Was: Glass Executive Bifocal)
>
[quoted text clipped - 11 lines]
>
> David
William Stacy, O.D. - 09 Dec 2006 19:09 GMT
oh and as to the differences between flat top and exec?  The exec has
"no jump" or double vision (when they are made correctly) at the seg
line.  Flat tops all have prismatic jump at the seg line.  The
difference between glass and plastic D segs is that the glass uses two
different indices of refraction glass, fused together so there is no
palpable "ledge" at the seg line as there is on all plastic D segs.

of course all execs have a ledge, but no jumping allowed...

w.stacy, o.d.
David Combs - 14 Dec 2006 14:00 GMT
>oh and as to the differences between flat top and exec?  The exec has
>"no jump" or double vision (when they are made correctly) at the seg
[quoted text clipped - 6 lines]
>
>w.stacy, o.d.

Thanks for the info!

So, for someone who likes executives (can switch eye-direction
from all the way left to all the way right, while keeping
the nose *still*, no-rotation-required) -- in your estimation,
are "flat-tops" (even) better?

(I was told by one seemingly-knowledgeable person that
they were *much* better, newer design, less distortion,
etc.)

Was he right?  wrong?

He also told me that executives were made only in the U.S. --
never got popular in Europe.

(of course(?) they like progressives there, but I can't
stand the idea of having to always twist my head to
look left and right.

THANKS!

David
William Stacy - 14 Dec 2006 20:48 GMT
>So, for someone who likes executives (can switch eye-direction
>from all the way left to all the way right, while keeping
>the nose *still*, no-rotation-required) -- in your estimation,
>are "flat-tops" (even) better?
>  

Not better in theory.  In practice, a 35 mm wide seg flat top works fine
for most, but you can't beat the exec or single vision for what you're
describing.

>(I was told by one seemingly-knowledgeable person that
>they were *much* better, newer design, less distortion,
>etc.)
>
>Was he right?  wrong?
>  

wrong on all 3 counts.  execs are a more recent design than flat tops,
have less prism, less jump, and are a better design for many people.

>He also told me that executives were made only in the U.S. --
>never got popular in Europe.
>
>  

may be true, as it for many years was a proprietory lens owned by
American Optical Corp.

>(of course(?) they like progressives there, but I can't
>stand the idea of having to always twist my head to
>look left and right.
>
>  

Then get an exec or a ft-35.  You can get a ft 45, but there's so much
jump and prism in the seg that I hate them.
David Combs - 22 Dec 2006 01:15 GMT
>>So, for someone who likes executives (can switch eye-direction
>>from all the way left to all the way right, while keeping
[quoted text clipped - 32 lines]
>Then get an exec or a ft-35.  You can get a ft 45, but there's so much
>jump and prism in the seg that I hate them.

Thanks so much!

David
 
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