Evidence that the natural eye is dynamic

Discussion in 'Eye-Care' started by Otis Brown, Sep 22, 2004.

  1. Otis Brown

    Otis Brown Guest

    Dear LarryDoc,

    You ask for "proof" about the effect that a
    plus or minus lens has on the refractive
    status of the natural primate eye.

    That proof has been supplied many times.
    I is so clear and so certain that I do not
    understand how you could miss the point.

    But then Dr. Judy states, essentially that

    All review of the results of animal
    studies is to be rejected and ignored.

    Under that circumstance I doubt that any
    SCIENTIFIC data can ever penetrate your mind.

    The Human Eye and the Plus Lens.

    I don't argue that you can PRESCRIBE a plus lens --
    for a number of obvious reasons.

    However I do believe that a number of highly motivated
    pilots could figure out that it is absolutly necessary
    if the wish to clear their distant vision
    BACK TO 20/20.

    This would involve the use of a STRONG plus lens,
    as well as the use of a plus-one (advocated by
    Professor Grosvenor) when in the home.

    This action would be under the control of the
    pilot himself.

    The bi-focal studies have a problem, in that they
    retain the minus lens and that fact INHIBITS
    recovery.

    Further, it is almost impossible to get a young
    child to use the plus (in the bi-focal) properly

    In addition, the child can not be taught to
    "push print", and read were the plus can
    and must have maximum "clearing" effect.

    But given all these "problems", the
    plus (in the bifocal) has been tested.

    The results (when properly done) by
    Francis Young and Kenneth Oakley showed
    that the single-minus went down
    at a rate of -1/2 diopter per year.

    This rate is confirmed by almost all
    following bifocal studies (see below)

    Clearly if you can prevent the -1/2 diopter
    per year (with STRONG use of a plus) you
    can PREVENT the development of a negative
    refractive state of the natural eye -- in the
    first place.

    No such preventive study has ever even
    been attempted -- although I have propose
    exactly that type of SCIENTIFIC study
    among engineering students in a four-year college.]

    So hear is a statement of these poorly run
    bifocal studies, for your interest.

    _______________


    Subject: From: How the Accommodation System Works

    Dear Mike,


    Subject: So show us evidence that myopes who wear glasses
    get worse than those who don't. Why do you refuse to
    address this point? Mike Tyner OD


    Here is a study by Leung and Brown, (1) that shows that the
    myopes who wear a strong single-vision minus lens go "down" at a
    rate of -0.61 diopters per year.

    You keep on insisting that both the test group and control
    group BOTH go down at the same rate.

    These were children so NO INSTRUCTION in the use of the plus
    could be given. The fact of a "blind study" would also prevent
    and reasonable instructions from being provided even IF these were
    not children.

    We have proposed a preventive study among college students
    where PRECISE instruction on the use of the plus MUST be provided.

    Since we know the "down" rate of college students is -1/3
    diopter per year (West Point), then if you can prevent this -1/3
    diopter per year from developing in the first place you can
    prevent the development of nearsightedness -- before it develops.

    But this would be a scientific (not medical) effort since
    there would be a test group and a control group, and the "null
    hypothesis" would be tested. The only detail would be that this
    COULD NOT BE a "blind" study. The students whould have to
    understand the goals and method of this type of
    engineering-scientific work.



    Best,

    Otis

    ***********************


    1. A recent study in Hong Kong showed what other studies have
    shown - wearing less than a full correction will slow the progress
    of the myopia. Children selected for the study were between the
    ages of 9 and 12. All were nearsighted, with -1.00 to -5.00 D of
    myopia. The children were separated into three groups. Each
    group was given a different type of eyeglasses to wear for the
    two-year period of the study. The first group wore single vision
    lenses with a full correction; the second group wore progressive
    lenses with a +1.50 add; the third group wore progressive lenses
    with a +2.00 add. All children were examined at 6-month intervals
    to check the progression of their myopia. Sixty-eight children
    completed the study. As expected, more undercorrection meant
    slower myopia progression.

    Minus vision lenses: - 1.23 D increase (2 year)

    Progressive lenses with +1.50 add: - 0.76 D increase (2 year)

    Progressive lenses with +2.00 add: - 0.66 D increase (2 year)


    Source: Leung JT, Brown B. Progression of myopia in Hong Kong
    Chinese schoolchildren is slowed by wearing progressive
    lenses. Optom Vis Sci 1999; 76:346, 354. Published
    10/07/00.


    ***********



    The answer is to look at the experimental data yourself.

    I answered this question about many times previously.

    The Young/Oakley "bifocal" study demonstrated that the
    children wearing a "straight" minus lens go "down" at a rate of
    -1/2 diopter per year.

    The chidren using the "plus" went "down" at 0.0 diopters per
    year. i.e., the plus could be effective for PREVENTION.

    More important than these studies are the "primate" studies
    where the results are always certain (using the term
    refractive-state).

    If you take a popluation of primates an place a minus lens on
    1/2 of them, then the primates with the minus-lens on will go
    "down" relative to the non-minus primates.
     
    Otis Brown, Sep 22, 2004
    #1
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  2. Any eye, human or primate will tend to adapt to whatever lens is
    placed before it.It does not necessarily develop a refractive error.
    When the lens is removed the vision of the animal will soon return to
    normal.

    According to Otis Brown a minus lens placed before a normal sighted
    individual will produce myopia. Admittedly if the lens is worn for a
    few days and then removed there will be a slight difficulty in seeing
    perfectly but conditions will soon return to normal.

    It is not true that all myopic eyes become more myopic as the years go
    by. My wife has been myopic since chilhood and now in her sixties has
    a -l prescription which has varied little throughout her life. The
    same applies to my sight. I have turned 80 and my prescription is less
    than it was when I was aged fourteen. Any optometrist of experience
    will have had similar patients.

    The plus lens therapy advocated by Otis Brown neither prevents the
    development of myopia nor does it improve it. He seems to suggest the
    fitting of plus lenses to children to prevent myopia whether or not
    they have shown any signs of its appearance. Perhaps we should all be
    fitted with lightning conductors to save us from a strike.

    The offered proof that one or two pilots have benefited from wearing
    plus lenses is hardly evidence. Perhaps we should have the opinions of
    the optometrists who treated them.
     
    Robin Parsons, Sep 27, 2004
    #2
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  3. Otis Brown

    A Lieberman Guest

    Otis,

    Please provide proof from a website. Not your website, not some
    hypothetical story, but a real bonifide medical journal website that others
    can read to evaluate your position. I bet you can't.
    The highly motivated pilot wants 20/20 vision. He doesn't care if it is
    corrected or uncorrected so long as he gets 20/20 vision. After all, there
    are no requirments for uncorrected 20/20 vision. Since there are no
    requirments of uncorrected 20/20, your statement of "absolutely necessary"
    is as usual, an incorrect fact.

    Allen
     
    A Lieberman, Sep 27, 2004
    #3
  4. Otis Brown

    Otis Brown Guest

    Dear Robin,

    You have been gone a long time!

    Some commentary.

    Best,

    Otis

    ***********


    Gospel according to Robin Parsons:

    Excellent. Say "change refractive status" ... and you will have it!


    It does not necessarily develop a refractive error.

    According to the "pure" Donders-Helmholtz concept and
    theory a focal status of 0.0 diopters is emmetropia.
    Refractive states that are not zero are a
    "refractive error".

    If you place a minus 2 diopter lens on a hyperopic primate (refractive
    status of +1/4 diopters, then the eye will naturally
    change from +1/4 diopter towards -1/4 diopters, thus going
    from hyperopia to myopia in about 60 days.

    If the animal lives in an "open-pen" and has his eyes
    mostly "in the distance", then his refrative
    status will change from -1/4 diopter to +1/4 diopter
    thus "returning to normal" as you say.

    It depends on what refractive state you call "myopia".
    I just reported what you would MEASURE in terms of
    refractive status. If you wish to call a minus
    refractive status of -1/4 dioper "myopia" then fine.


    Admittedly if the lens is worn for a
    If the primate is living in an "open pen" environment.
    Primates in cages are slightly myopic, and stay that
    way -- for obvious reasons. They don not "return to normal".

    But of course. Fine for you!
    I NEVER use the word "therapy". As far at a person
    clearing his distant vision from 20/50 to 20/30, it
    would be wise if he sees this result himself -- by
    his own efforts. That is the ONLY way he is
    going to trust his ability, motivation and
    intelligence in this matter. Dr. Stirling Colgate
    did it -- but he did not wait for anyone to tell him
    how do do it.


    He seems to suggest the
    I agree that an OD can not do this -- although I wish they
    could. It comes down to a decision the person (or pilot)
    will have to make himself. My sister's kids did it, when
    they realized that the "trade-off" was "take over control"
    and always clear your vision whenever necessary -- thus
    passing the Snellen-DMV, and avoiding any use of the
    minus lens.


    Perhaps we should all be
    Prevention of this nature is honestly difficult. A great
    deal of experimental data suggests that early use of
    the plus for prevention is effective, but, again,
    it must depend on the individual himself to
    decide the issue. The plus is sold all over
    the place, and if the person gets the "right idea",
    he can keep his distant vision clear through
    high school, college and graduate school.

    The scientific proof is that if you place a population of
    normal primate eyes in a sharply confined environment,
    their refractive status moves negative proportional
    to the delta in the average value of accommodation.
    The resultant curve follows the e ^ (-t/Tau) function
    and the correlation coefficient is 0.97.

    The pilots who cleared their vision speak for themselves,
    and pass the required 20/20 line.


    Perhaps we should have the opinions of
    the optometrists who treated them.

    They of course "gave up" on the OD who gave them
    a -1.0 diopter lens. They simply realized that
    they had to "take control" and do it under
    their own control.

    Best,

    Otis
     
    Otis Brown, Sep 28, 2004
    #4
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