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Home > Archive > Vision > June 2005 > My Electroretinography (ERG) Results Questions, Please
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My Electroretinography (ERG) Results Questions, Please
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| Robert11 2005-06-27, 10:01 am |
| Hello:
68 year old white male; fairly good health overall.
Last year, and just recently, I had a Visual Electrophysiology, ERG test
done.
Results were: "full field flash ERG b-wave amplitudes continue to be
abnormal for both scotopic
and photopic stimuli. Amplitudes are 50% lower than a year ago"
I will be seeing my regular opthamologist in about a week, but would very
much like to know a bit more about my condition so I can ask him the most
meaningful questions.
Tried to read up on it from various sites, but find the explanations
confusing.
So, thought I'd ask here, where I have obtained very good information
before, for which I again say thank you for all the time various folks have
taken in answering some of my questions.
Guess I'm really worried about losing my sight with this. Sounds pretty
scarry.
Funny thing is that I truly don't perceive of any change in my vision over
the last few years, either during the daytime, or at night.
a. Is it (usually) degenerative ?
b. Is loss of sight, eventually, pretty much a certainty ?
- Is it a slowly progressive disease ? Time frame (I'm 68 now) ?
c. Is this the same as RP (Retinal Pigmentosa) ? Exactly what is it that
I likely have ?
d. What specific questions should I be asking my opthamologist ?
- Are there other tests to pin this down more definitively that I
should ask about ?
Any information, suggestions, etc., would be most appreciated.
Should also ask, I guess, if there are any "specialists" for this in the
Boston area, or elsewhere ?
Sugtgested web sites relative to ?
Much thanks,
Bob
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I am not an ERG specialist but I do know something about it.
The ERG b-wave is caused by the combined electrical activity of the retinal
cells that are connected to and adjacent to the photoreceptor cells
(amacrine, Mueller, etc.). Any pathological process that affects these
cells can result in a decreased b-wave response. Some examples include
reduced blood supply, degenerative changes, toxins, etc. This is the
problem with ERG testing-- it does not give specific information. However,
when combined with other tests, like a good funduscopic exam, visual field
analysis, etc. it can be useful in developing a diagnosis.
The ERG is most often used as a test to support the diagnosis of a
degenerative disease, like retinitis pigmentosa, but not necessarily limited
to that condition. It sounds as if the person interpreting your ERG results
is indicating that the results are consistent with some type of degenerative
process.
Retinitis pigmentosa is actually a disease that can occur with a wide
variety of characteristics. Usually it has a genetic component. Usually it
occurs at an age earlier than your age but not always. Usually it affects
the periphery of the retina first and then later it affects the central
vision. Usually it affects your night vision first. Usually it produces a
characteristic appearance of the retina when it is viewed in a funduscopic
exam. Usually it results ultimately in total loss of functional vision
although the rate of progression varies.
Ask your ophthalmologist what all the positive findings are that make him
suspect a degenerative disease. Ask him what exact types of degenerative
disease he suspects. Ask him if there are some genetic tests that can be
performed that confirm the diagnosis (some of the mutations that cause
degenerative diseases have been discovered and genetic tests can be
performed to screen for them although they are probably only done in a
research setting in just a handful of labs at this point).
I hope this is somewhat helpful. Feel free to post additional information
when you get it so we can provide more targeted advise.
RM
PhD OD
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| Dr Judy 2005-06-27, 10:01 am |
| "Robert11" <rgsrose@notme.com> wrote in message
news:5KidnemuM4ZsaSbfRVn-pg@comcast.com...
> Hello:
>
> 68 year old white male; fairly good health overall.
>
> Last year, and just recently, I had a Visual Electrophysiology, ERG test
> done.
>
> Results were: "full field flash ERG b-wave amplitudes continue to be
> abnormal for both scotopic
> and photopic stimuli. Amplitudes are 50% lower than a year ago"
>
> I will be seeing my regular opthamologist in about a week, but would very
> much like to know a bit more about my condition so I can ask him the most
> meaningful questions.
>
> Tried to read up on it from various sites, but find the explanations
> confusing.
> So, thought I'd ask here, where I have obtained very good information
> before, for which I again say thank you for all the time various folks
> have taken in answering some of my questions.
>
> Guess I'm really worried about losing my sight with this. Sounds pretty
> scarry.
>
> Funny thing is that I truly don't perceive of any change in my vision over
> the last few years, either during the daytime, or at night.
>
> a. Is it (usually) degenerative ?
>
> b. Is loss of sight, eventually, pretty much a certainty ?
>
> - Is it a slowly progressive disease ? Time frame (I'm 68 now) ?
>
> c. Is this the same as RP (Retinal Pigmentosa) ? Exactly what is it
> that I likely have ?
>
> d. What specific questions should I be asking my opthamologist ?
>
> - Are there other tests to pin this down more definitively that I
> should ask about ?
>
> Any information, suggestions, etc., would be most appreciated.
>
> Should also ask, I guess, if there are any "specialists" for this in the
> Boston area, or elsewhere ?
> Sugtgested web sites relative to ?
The ERG is a test of rod/cone function, it does not diagnose a particular
condition as many conditions can have an abnormal ERG.
To answer your questions, we would need to know which condition you have.
Even then, outcomes vary considerably between individuals so the best
answers will come from your own doctor. However, given your age and the
fact that your vision is still good, you likely have one of the disorders
that is not severe. Most the conditions with severe vision loss occur early
in life and the led to blindness by the age you are now.
Dr Judy
>
> Much thanks,
> Bob
>
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