EyeglassExam: Meaning Of "Red-Green Corrected" ?

Hello:

Received a prescription from an opthamologist for new eyeglass lenses during
visit.

He mentioned that I should make sure to request in the future that any new
eye exams, and prescriptions,
say "Red-Green Corrected".

Might someone please explain this a bit for me.

e.g. Is it for the prescription exam, or in the making of the lenses ?
what exactly is being corrected ?
etc. ?

Should have asked him, but things were rushed, and i didn't.

Thanks,
B.

I've been in the business a long time and don't know what that means.
Ask him for clarification.

w.stacy, o.d.


> Hello:
>
> Received a prescription from an opthamologist for new eyeglass lenses during
> visit.
>
> He mentioned that I should make sure to request in the future that any new
> eye exams, and prescriptions,
> say "Red-Green Corrected".
>
> Might someone please explain this a bit for me.
>
> e.g. Is it for the prescription exam, or in the making of the lenses ?
> what exactly is being corrected ?
> etc. ?
>
> Should have asked him, but things were rushed, and i didn't.
>
> Thanks,
> B.
>
>

perhaps he means that the prescription should be red-green balanced.
to assure the patient is not overminused and that both eyes are equal.

<(E-Mail Removed)> wrote in message news:(E-Mail Removed) oups.com...

> perhaps he means that the prescription should be red-green balanced.
> to assure the patient is not overminused and that both eyes are equal.

Perhaps he means achromatic, which is a term known to lensmakers.
After that, there is apochromatic (corrected for three colors c.f. two
for achromatic).

Well, I noticed here that some eyeglasses are aspheric. So, why not
color-corrected as well. There's a bunch of folks for who good enough
is not enough, so why not go the whole ten yards. Maybe it can be done
for contacts and IOLs.

Will there be some special eyeglasses for pseudomyopes. My dentist
is wearing little telescopes sticking out from his eyeglasses -- maybe I
should have had some of those.

--
Dicky
(implanted now)

he means red/green balance as pclarkii said correctly.

Personally, I don't think the guy knows what he is talking about (the
ophthal, not pclarkii) as:

1) ophthals can't refract
2) not many people do red/green balance
3) I can't do it and I know what I am supposed to be looking for
4) easy to stuff it up if you are an active accommodater, you will
easily get more minus than you need
5) push plus method is much more effective
6) finish in a trial frame with +/- 0.25 flippers to correct for muscle
tone and proximal factors.

cheers,

dr grant

The theory is, we want to get you to determine if the letters are
sharper on the red or green background.This is using chromatic
aberration, or green being bent more easily than red to get the resting
point of the script. If the correction is too strong on the + side, the
letters look sharper on the red background, if too much minus or not
enough plus, then the letters look sharper on the green.

This does not work well, in my experience, for hyperopes, who like to
accommodte and are used to it, so get too low a script often with this
method, and myopes, especially those who do a lot of near work and have
an accommodative component to their script, and again get too much
minus correction which can lead to asthenopia.

dr grant

In article <(E-Mail Removed). com>,
CatmanX <(E-Mail Removed)> wrote:
>The theory is, we want to get you to determine if the letters are
>sharper on the red or green background.This is using chromatic
>aberration, or green being bent more easily than red to get the resting
>point of the script. If the correction is too strong on the + side, the
>letters look sharper on the red background, if too much minus or not
>enough plus, then the letters look sharper on the green.
>
>This does not work well, in my experience, for hyperopes, who like to
>accommodte and are used to it, so get too low a script often with this
>method, and myopes, especially those who do a lot of near work and have
>an accommodative component to their script, and again get too much
>minus correction which can lead to asthenopia.
>
>dr grant
>

MY problem is that when looking at eg an ad that has green and
red letters near each other, one of them (I forget which, I think
it was the red) seems, like in 3-D, to stand up out of the paper
and be closer to my eyes.

Any idea what that's all about?

Thanks,

David

David Combs wrote:
>
> MY problem is that when looking at eg an ad that has green and
> red letters near each other, one of them (I forget which, I think
> it was the red) seems, like in 3-D, to stand up out of the paper
> and be closer to my eyes.

Completely normal phenomenon. The red and green wavelengths are
refracted to a different extent (red bent less, green more), setting up
a disparity at the junction of the colors that give an (erroneous) depth
sensation. Ignore it, or filter it (red OR green filters would do).

w.stacy, o.d.

In article <ajJuf.45771$(E-Mail Removed)> ,
William Stacy <(E-Mail Removed)> wrote:
>David Combs wrote:
> >
>> MY problem is that when looking at eg an ad that has green and
>> red letters near each other, one of them (I forget which, I think
>> it was the red) seems, like in 3-D, to stand up out of the paper
>> and be closer to my eyes.
>
>Completely normal phenomenon. The red and green wavelengths are
>refracted to a different extent (red bent less, green more), setting up
>a disparity at the junction of the colors that give an (erroneous) depth
>sensation. Ignore it, or filter it (red OR green filters would do).
>
>w.stacy, o.d.

Thanks for the info.

However, of all the people I've mentioned it to,
I'm the only one who's experienced it.

Plus, you're the only o.d. or similar who even
recognizes that it happens!

Thanks for the nice explanation.

David