Re: Change in lens power with distance

On Wed, 20 Feb 2008 13:51:31 -0600, Robert Martellaro
<robopt@xxxxxxxxxx> wrote:

On Wed, 20 Feb 2008 01:53:02 -0600, John O'Flaherty <quiasmox@xxxxxxxxx> wrote:

I wonder if someone could help me understand something about glasses.
I am 62, myopic, and don't think I have any accommodation to speak of.
My prescription is about -2,-2.25, averaging in the astigmatism.
When I got my eyes checked, I mentioned that I wanted a special pair
of glasses to watch TV, at a distance of 11 ft. (3.35 m),


because I found my old glasses blurry at that distance.

That's a common complaint when the Rx changes towards less minus or more plus.
Has it changed? Are your eyes healthy? Post the new unmodified (distance) Rx and
the lens powers of the old glasses.

I had (2004):
-2.5 -.5 90
-3.0 -.5 50

add +2.25

I now have (2008)
-1.75 -.5 90
-2.25 -.5 50

add +2.25

It's changed a lot. It may be worth saying that the older
prescription was obtained by an automatic instrument, while the new
one was obtained by a phoropter and "is this better, or is this
better"? How much variation will there be between these two methods?

I have had one pair of glasses made to the new script, and the
bifocals are almost unusable, because the lower segment has no
remaining correction at all, which may be ok for reading, but I don't
need glasses for reading. What I do need is some way to see the
speedometer of my car clearly, and to see items on grocery store
shelves or on a table in front of me without removing my glasses. I
guess that's another matter, along with the fact that the bifocal line
lies almost within my level-headed field of vision.

Anyhow, referring to the original problem, the old glasses were ok
for driving, but not sharp and clear for watching TV, while the new
ones are good for watching TV but not sharp and clear for driving. I'd
like to order a new pair of bifocals that will be sharpest for
driving. At this point, I'm thinking of going with -2, -2.5 (restoring
one quarter diopter of convergence), with add of 1.5, which would make
the bifocal segment equal to my current computer glass prescription,
which is -.5, -1, and which works fine.
--
John
.

Relevant Pages

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  • Re: Prescription Question (old vs new)
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    (sci.med.vision)
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  • Re: Prescription Question (old vs new)
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    (sci.med.vision)
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