My Electroretinography (ERG) Results Questions, Please

Discussion in 'Optometry Archives' started by Robert11, Jun 24, 2005.

  1. Robert11

    Robert11 Guest

    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
     
    Robert11, Jun 24, 2005
    #1
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  2. Robert11

    Robert11 Guest

    Hello:

    Should have included that the test results also had
    the statement: "Results are consistent with widespread rod-cone dystrophy"

    Bob
     
    Robert11, Jun 24, 2005
    #2
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  3. Robert11

    RM Guest

    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
     
    RM, Jun 26, 2005
    #3
  4. Robert11

    Robert11 Guest

    Hello:

    Just would like to say a quick thank you for such an excellent explanation.
    Just what I was seeking.

    Really appreciate the time you took to write it.

    Will post again after I have some more info.

    Thanks,
    Bob
     
    Robert11, Jun 26, 2005
    #4
  5. Robert11

    Dr Judy Guest

    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
     
    Dr Judy, Jun 26, 2005
    #5
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