Medical Forum / General / Vision / June 2006
Question About "Add" Value
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Rich - 25 Jun 2006 21:11 GMT 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
otisbrown@pa.net - 25 Jun 2006 21:53 GMT > Greetings, Is it 0.5 + 2.00=2.5 diopters
Otis> That is correct.
(I am not an OD -- but I think they will agree.)
> Rich Rich - 25 Jun 2006 22:08 GMT >> Greetings, > [quoted text clipped - 5 lines] > >> Rich 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
Mark A - 26 Jun 2006 00:36 GMT > 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 [quoted text clipped - 3 lines] > > Rich That is correct.
otisbrown@pa.net - 26 Jun 2006 02:00 GMT 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:
> 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? 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
> Thanks, > > Rich A Lieberman - 26 Jun 2006 02:05 GMT > 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. 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
otisbrown@pa.net - 26 Jun 2006 02:10 GMT 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
++++++++
> > 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. [quoted text clipped - 7 lines] > > Allen odisbrown@pa.net - 26 Jun 2006 02:52 GMT 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
Rich - 26 Jun 2006 02:56 GMT > Dear Rich, > [quoted text clipped - 24 lines] >> >> Allen 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
Mark A - 26 Jun 2006 04:42 GMT > 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 [quoted text clipped - 43 lines] > > 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.
Nooblet - 27 Jun 2006 14:05 GMT 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.
Quick - 26 Jun 2006 02:26 GMT > Dear Rich, > > I will make this statement as an Engineer. This begs the question of what you make all your other posts as...
-Quick
Anon E. Muss - 25 Jun 2006 22:15 GMT >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. The "Add" is added to the distance prescription, so in your case the maximum power in the reading zone should be +2.50D.
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