I am very near-sighted - -10.75 R, -8.25 L. Before I went in for my
annual exam last week, my L lens prescription was -9.25. In the exam, I
could see only 20/40 with my L lens. So the doctor changed the
prescription to -8.25. Now I am confused. If my eyes got worse,
shouldn't the -9.25 have been increased to -10 or so? It seems
backwards to me. Can anyone explain?
otisbrown@pa.net - 06 Aug 2005 13:47 GMT
Dear Tenplay,
You should ask you doctor about this.
If you want the stronger minus -- I am
certain he will provide it.
There are doctors who believe that
a very strong minus results in
your vision going "down" at a
steady rate -- and will attempt
to "under-prescribe" for that
reason.
You should ask him to explain, and
-- if that is the case -- then he
should have explained before
he gave you a "reduced" prescription.
Best,
Otis
(Engineer)
p.clarkii@gmail.com - 07 Aug 2005 14:29 GMT
if you are a hammer, everything looks like a nail
Dr. Leukoma - 06 Aug 2005 14:06 GMT
> I am very near-sighted - -10.75 R, -8.25 L. Before I went in for my
> annual exam last week, my L lens prescription was -9.25. In the exam, I
> could see only 20/40 with my L lens. So the doctor changed the
> prescription to -8.25. Now I am confused. If my eyes got worse,
> shouldn't the -9.25 have been increased to -10 or so? It seems
> backwards to me. Can anyone explain?
You neglected to say whether the reduction in prescription made your
vision better or worse.
The goal of prescribing for myopia is to give only the power that is
required to achieve clear, comfortable vision at far...no more and no
less. There are various techniques for determining this. The eye
doctor must have determined that your prescription was too strong, not
too weak, and made the necessary adjustment. By itself, a Snellen
acuity of 20/40 says nothing about the cause. You could be farsighted,
nearsighted, astigmatic, a combination of the above, or have a retinal
lesion.
DrG
Mike Tyner - 06 Aug 2005 14:23 GMT
>I am very near-sighted - -10.75 R, -8.25 L. Before I went in for my annual
>exam last week, my L lens prescription was -9.25. In the exam, I could see
>only 20/40 with my L lens. So the doctor changed the prescription
>to -8.25. Now I am confused. If my eyes got worse, shouldn't the -9.25
>have been increased to -10 or so? It seems backwards to me. Can anyone
>explain?
Normally this means during refraction you told your doctor that -8.25 was
just as clear as -9.25.
Typically myopia increases for several years and then levels off. At that
point, many people see some slight improvement. Some even get lots better.
Between ages 30 and 50, the whole population changes in that same direction:
hyperopes get worse and many myopes get better, tho usually not much.
-MT
William Stacy - 06 Aug 2005 15:03 GMT
> Between ages 30 and 50, the whole population changes in that same direction:
> hyperopes get worse and many myopes get better, tho usually not much.
Isn't it interesting that this process doesn't fit some
pseudo-scientists' pet "theories", so they can't accept, acknowledge or
even understand it? I find it amusing.
w.stacy, o.d.
Dr. Leukoma - 07 Aug 2005 14:59 GMT
> I am very near-sighted - -10.75 R, -8.25 L. Before I went in for my
> annual exam last week, my L lens prescription was -9.25. In the exam, I
> could see only 20/40 with my L lens. So the doctor changed the
> prescription to -8.25. Now I am confused. If my eyes got worse,
> shouldn't the -9.25 have been increased to -10 or so? It seems
> backwards to me. Can anyone explain?
Since I glossed over the fact that this patient is wearing RGP lenses,
I will add to what others have already written by saying that I have
long observed a trend in RGP lens wearers of having to adjust the
prescription downward over time. Presumably this is due partly to the
effects of changing corneal shape as a result of wearing the lenses.
DrG