Question About "Add" Value

Greetings,

I am primarily Presbyopic & my prescription I OD & OS +0.5; add 2.00. I
have progressive lenses & my question is about the reading strength of
the lenses. Is it 0.5 + 2.00=2.5 diopters or just 2.00 diopters at the
bottom of the lens.
Thanks.

Rich

 

Is it 0.5 + 2.00=2.5 diopters

Otis> That is correct.

(I am not an OD -- but I think they will agree.)

 

Thank you for the reply. If I were to get bi-focal glasses for computer
use, the prescription would be something like OD, OS 1.5, add 1.00 &
that would yield a 2.5 diopter lower lens to read with?

Thanks,

Rich

 

That is correct.

 

Dear Rich,

I will make this statement as an Engineer.

I do not know how old you are, but your refractive state is +0.5
diopters
as you state. The "range" of accommodation (stop-to-stop) reduces
as we get older. If you "range is 2.5 diopters (let us say), then
you can see clearly through a +0.5 diopter lens, down to
about a distance of about -2 diopters. ( -2.0 diopters is
a distance of about 20 inches -- or normal reading distance.)

You might take you glasses off and check this. If at 20 inches
the reading is blurry, then you will need some "plus" to read.

You can obtain a "simple" plus in the drug store off-the-shelf.

You might try a +1.25 diopter lens, and see if that meets
your "near" requirements.

And further, you might check your distance vision on my
site:

www.myopiafree.com

on Eye-Chart #2 and determine your visual acuity
with no plus.

These are easy checks, and do not require OD involvement.

Just "fun" things to do.

To further respond:

Otis> If you Snellen is good, then you need to obtain a "weak" plus,
so that reading or the "computer" are comfortable for you.

Otis> Only YOU can check this -- if you wish.

Best,

Otis

 

Dear Rich,

Please disregard Otis's postings. He is not in the medical profession and
not in any position to give medical advice like above.

Thank you!

Allen

 

Dear Rich,

Please disregard Allen's postings.

He thinks you are intellectually incompetent -- and
I would bet that you are not.

To much "paternalism" here. AFTER you have
done these simple checkes YOURSELF -- you
can go back to your OD, and talk to him/her about
them.

Think for yourself.

Otis

++++++++

 

This begs the question of what you make all your
other posts as...

-Quick

 

Dear Rich,

Subject: Think for yourself.

To expand a bit further, when I say "think for yourself,"
I DO MEAN that you should ignore scientifically
verifiable human evidence, commonly-accepted
beliefs, and standards of practice from evidence-based
medicine.

I DO MEAN that you should ignore ALL of those "majority
opinion" trappings and instead pay attention to the widom
found here:

www.chinamybunghole.com

You will find many on sci.med.vision who disagree with me, but
perhaps NONE as adamantly as my niece who
listened to me and became highly myopic nonetheless.

Best,

Odis
Avuncular, but Insane

 

To all that responded to my original question, I thank you. To the
optometrists on the board, I did just visit one & had my eyes examined.
My question was just a technical question & replies from both
professionals & "buffs"(for want of a better term) were helpful. The
reason I asked was that I had been prescribed progressive lenses with
the aforementioned prescription after stating that I spend all day on a
computer at work, not to mention a couple of hours at home. I currently
had a prescription pair of glasses from another optometrists 4 years
old(unknown diopter powers & I had forgotten them at work before my
appointment with the new optometrists). I had told the former
optometrist(from another state) that I primarily need them for computer
use. He prescribed a bi-focal with an intermediate power on top for the
screen & lower for reading. To this day, the prescription is perfect for
my needs. The single power intermediate is not quite strong enough for
me to read paper documents, so I need the bi-focal. I can get by with a
single lower power reading glass(which I did when these frames broke)but
prefer a stronger bi-focal. The problem is that the new optometrist told
me progressives were just what I needed for computer use, to read with &
to correct the slight fuzziness I have at distance. No sooner did I sit
down in front of a computer when I realized that they were functionally
useless for me at work. I am a mail service pharmacists who sits at dual
17" LCD monitors with an image of a prescription on the left screen &
various data on the right(patient profile, what the tech entered for the
prescription, etc.). This requires constant checking back & forth with
some speed for efficiency) to make sure the data-entry matches the
prescription. With the older bi-focals all I needed to do was move my
eyes back & forth. The progressives had such a narrow intermediate field
that it not only took constant head movements to acquire sharpness but
it also slowed me down to the point of uselessness. I usually ended up
just tilting my head all the way back to read the screen through the
near area & not the intermediate. However, after research, I discovered
that only near vision progressives are appropriate for use on a computer
& I liked the progressive for walking around, so I went back & changed
them to transitions(I live in Arizona, very sunny)& decided to order a
new 2nd pair of inexpensive computer-use bi-focal on-line to replace my
old one(frames 10 years old, lenses 4 years old, scratched with a slight
crack from trying to pop them back into a slightly bent frame). Hence,
my questions about how to order the "add" value. I'm just surprised that
the computer screen appears clear at 26" through the 2.5 diopter lowest
part of the progressives. I suppose I should take them to another shop
to confirm the correctness of the new prescription & obtain the powers
of my old bi-focals.
I welcome any insights on my saga & any flames for posting a needlessly
unsolicited long post.

Thanks again,

Rich

 

Ideally, you should measure the distance from your eyes to your monitor and
have an OD prescribe an appropriate pair of bi-focals or specially made
computer progressives for that purpose (that would place computer monitor
distance vision on the top and then you would add whatever power is
necessary to get to +2.50 for your reading area on the bottom).

Progressives are very difficult to fit properly, and a poor lens or frame
fitting could be causing the problems (or discrepancies) you are noticing
compared to what you expected. Or the lenses could have been made wrong. I
would take them to a different optical shop and have them measured (even
Wal-Mart optical will do this for you).

There are specially designed progressive lenses available for computer usage
such as Zeiss Gradal RD, but an experienced optician could design a pair
using regular progressives (with a high quality progressive lens design) to
function as computer lenses suing your custom Rx measured by your OD.
Progressives have some advantages, but your vision will never be as good
with progressives as it could be with bi-focals at those two exact
distances.

 

So if some one was -5.00 and had and add of +1 the would really have be
reading through -4?

I have always wondered this.. Thanks.