Special vision test for computer glasses?

I'm going to be getting glasses to use with a new laptop
computer. I assumed that the correct add would just be a
function of the working distance form the eye to the
computer's display.

But then I saw claims that because of all the little dots,
the eye focuses differently on a computer screen than it
would on printed text at the same distance. In fact,
there's a product designed specifically for determining the
correct refraction for computer use. It uses a simulated
computer display to do the eye test. The implication is
that you would get a different result than using an eye
chart at the same distance. Here's the link:

http://www.prio.com

And here's a picture of the testing device:

http://www.prio.com/consumers/solution.cfm

Frankly, this looks like pure BS to me. But I've been
fooled before. What do the experts think?

> http://www.prio.com/consumers/solution.cfm
>
> Frankly, this looks like pure BS to me. But I've been
> fooled before. What do the experts think?
>
>

You are right on. It IS pure BS. I've looked at their research and
THEIR OWN DATA proves they are screwed up; they just don't know how (or
refuse to) understand it.

w.stacy, o.d.

"Sherman" <(E-Mail Removed)> wrote in message
news:457b4b98$0$1986$(E-Mail Removed) news.com...
> I'm going to be getting glasses to use with a new laptop
> computer. I assumed that the correct add would just be a
> function of the working distance form the eye to the
> computer's display.
>
> But then I saw claims that because of all the little dots,
> the eye focuses differently on a computer screen than it
> would on printed text at the same distance. In fact,
> there's a product designed specifically for determining the
> correct refraction for computer use. It uses a simulated
> computer display to do the eye test. The implication is
> that you would get a different result than using an eye
> chart at the same distance. Here's the link:
>
> http://www.prio.com
>
> And here's a picture of the testing device:
>
> http://www.prio.com/consumers/solution.cfm
>
> Frankly, this looks like pure BS to me. But I've been
> fooled before. What do the experts think?


There are two issues:

1. Is there a difference in the Rx with their method of using a computer
screen instead of a chart (both at computer distance)?

2. What is the difference in the lens they sell, compared to other computer
lenses?

I don't know anyone who always views the computer screen at the same exact
distance each time, or views the entire screen at the exact same distance.
It is hard to believe that their measurement technique with an actual
computer screen will come up with a different Rx compared to a regular chart
held at computer distance.

If the distance alone was a factor, then it could easily be corrected by
moving further or closer to the screen by a few inches.

Is there something about the lens that is an improvement over other computer
lenses. I doubt it, except that most computer lenses are made from a normal
Rx with distance and reading power without a specific measurement of
computer distance, and a 'standard" adjustment (instead of a custom
measurement) is made from the reading power to the computer power to achieve
the optimal computer power in the upper portion of the lens. For example, I
believe that Zeiss Gradal RD always assumes that the right power for
computer distance is .50 subtracted from the reading power.

So their could be some advantage for taking a custom Rx to the computer
distance, but I don't think using an actual computer screen helps, and a
good OD could come up with the exact Rx to make a pair of customized
computer glasses with any of the name brand lenses like Zeiss Gradal RD.

Mark A wrote:

> Is there something about the lens that is an improvement over other computer
> lenses. I doubt it, except that most computer lenses are made from a normal
> Rx with distance and reading power without a specific measurement of
> computer distance, and a 'standard" adjustment (instead of a custom
> measurement) is made from the reading power to the computer power to achieve
> the optimal computer power in the upper portion of the lens. For example, I
> believe that Zeiss Gradal RD always assumes that the right power for
> computer distance is .50 subtracted from the reading power.
>

Confused here -- "optimal computer power in the upper portion of the
lens" makes no sense to me, especially with a lens like the Gradal RD,
which I understand is designed to allow a presbyope the ability view
with clarity far-intermediate targets at 2 or 3 meters through the
upper portion of the lens. Near-intermediate viewing (computer screens)
would be through the middle area of the lens...correct?

http://www.zeiss.de/c125679b00315836...25679e004c6aa9

bg

"Burke Gilman" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Confused here -- "optimal computer power in the upper portion of the
> lens" makes no sense to me, especially with a lens like the Gradal RD,
> which I understand is designed to allow a presbyope the ability view
> with clarity far-intermediate targets at 2 or 3 meters through the
> upper portion of the lens. Near-intermediate viewing (computer screens)
> would be through the middle area of the lens...correct?
>
> http://www.zeiss.de/c125679b00315836...25679e004c6aa9
>
> bg

Yes, that is correct. The Zeiss Gradal RD has a wider intermediate area that
is used for computer distance. As you mentioned, and unlike a normal
progressive, the upper portion does not have the correct distance power
(usually 2-3 meters max), so you cannot use them for driving.

Also, some opticians use regular progressives to make custom computer lenses
with the upper portion optimized for computer distance, and the lower
portion for reading, and one cannot even see clearly at 2-3 meters in the
upper portion of the lens. In theory this gives a larger area for computer
distance, but is less flexible in seeing beyond that (like being able to see
someone sitting across the desk from you).

If you go the custom route, you can do whatever you wish, but as you say the
Zeiss Gradal RD does allow one to see up to 2-3 meters if you give them a
normal progressive Rx and they make the standard adjustment.

Mark A wrote:
> "Burke Gilman" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed) oups.com...
> > Confused here -- "optimal computer power in the upper portion of the
> > lens" makes no sense to me, especially with a lens like the Gradal RD,
> > which I understand is designed to allow a presbyope the ability view
> > with clarity far-intermediate targets at 2 or 3 meters through the
> > upper portion of the lens. Near-intermediate viewing (computer screens)
> > would be through the middle area of the lens...correct?
> >
> > http://www.zeiss.de/c125679b00315836...25679e004c6aa9
> >
> > bg
>
> Yes, that is correct. The Zeiss Gradal RD has a wider intermediate area that
> is used for computer distance. As you mentioned, and unlike a normal
> progressive, the upper portion does not have the correct distance power
> (usually 2-3 meters max), so you cannot use them for driving.
>
> Also, some opticians use regular progressives to make custom computer lenses
> with the upper portion optimized for computer distance, and the lower
> portion for reading, and one cannot even see clearly at 2-3 meters in the
> upper portion of the lens. In theory this gives a larger area for computer
> distance, but is less flexible in seeing beyond that (like being able to see
> someone sitting across the desk from you).
>
> If you go the custom route, you can do whatever you wish, but as you say the
> Zeiss Gradal RD does allow one to see up to 2-3 meters if you give them a
> normal progressive Rx and they make the standard adjustment.


Am I correct in my understanding that the Gradal RD always has 0.50 in
the upper portion of the lens and that the lower areas simply add more
*diopter* as needed to provide the viewer with clarity at closer
ranges?
-bg

Burke Gilman wrote:
>
> Am I correct in my understanding that the Gradal RD always has 0.50 in
> the upper portion of the lens and that the lower areas simply add more
> *diopter* as needed to provide the viewer with clarity at closer
> ranges?


roughly correct. I think they also have rather wider intermediate and
near zones than do conventional progressives.

w.stacy, o.d.

actually, I should add that the .5 in the distance is in addition to any
distance Rx that has been prescribed.

w.stacy, o.d.

William Stacy, O.D. wrote:
> actually, I should add that the .5 in the distance is in addition to any
> distance Rx that has been prescribed.
>
> w.stacy, o.d.



Interesting that some computer glasses are chosen for viewing the
screen through top portion of the lens. My purposes for an occupational
progressive are more conventional, however: I need to see clearly and
find objects at room distances -- up to 3 meters, no more, but also
need to read up-close and view computer screens at more than arm's
length. I do require distance correction also, but that's being
accomplished with contacts (+1.25) and I intend to keep wearing the
contacts all the time. Instead of continuing to rely upon an assortment
of OTC readers for near and intermediate distances, I'm thinking the
Gradal RD might provide an optimal solution for my sometimes demanding
"room distance" requirements -- provided I can find a pair. -bg

Mike Tyner wrote:
> "Burke Gilman" <(E-Mail Removed)> wrote
>
> > Am I correct in my understanding that the Gradal RD always has 0.50 in
> > the upper portion of the lens and that the lower areas simply add more
> > *diopter* as needed to provide the viewer with clarity at closer
> > ranges?
>
> Yes.. if your distance prescription is +1.00 and your near "add" is +2.00,
> RD lenses are modified to +1.50 for distance with a +1.50 add (still
> totaling +3.00 at near.)
>
> There are many benefits and one of them is that +1.50-add progressives will
> always be "wider" than +2.00 progressives of the same design.
>
> I wear generic progressives modified this way, and the blur driving is
> tolerable for short trips in daylight.
>
> -MT


Ok, I see. The Gradal RD, for the upper area of the lens, always adds
+0.50 to whatever the user's distance prescription is and that makes
the "distance" area of the lens a bit blurry for actual far-distance
viewing, but possibly tolerable for far-distance viewing over short
period of time.

Question: I wear +1.25 contacts for distance viewing and continue to do
so. On top of the contacts, my prescription calls for a near "add" of
+2.50 for fine reading and +1.25 for reading a computer screen at arm's
length. If this prescription is applied to an order for a pair of
Gradal RD, then what will these lenses actually provide? (I'm thinking
it would be an actual +0.50 in the upper part of the lens, but can't
figure what the lower up-close viewing area of the lens would provide
with the Gradal RD design.) -bg