Scientific truth (i.e., facts) that determine the eye's behavior

Discussion in 'Eye-Care' started by Otis Brown, Jul 8, 2004.

  1. Otis Brown

    Otis Brown Guest

    Dear Friends,

    I believe in the simplest of tests -- to determine the effect that the
    minus lens ALWAYS has on the refractive status of the natural eye.

    If this result were not ALWAYS repeatable, and the
    same result were not always the same -- then I would
    quit arguing for prevention -- on the basic of scientific
    fact -- not on the basic of some ones improper understanding
    of the natural eye as a dynamic system.

    Medicine is "separate" from science -- in the sense
    that medical people can not translate this basic
    science, and these basic facts into effective
    prevention.

    Dr. Colgate did understand and effectily
    prevent his own nearsightedness.
    It is clear that other motivated engineers and
    pilots have done the same thing -- but always
    BEFORE someone put a minus lens on them.

    Tragically, the "man in the street" simply will
    not listen to advocacy for prevention -- until
    it is too late to do anything about it.

    [Reference: Dr Raphaelson -- "The Printer's Son]

    Now who is responsible for that?

    Can we blame the ignorance and lack of motivation
    of the parents and children. Yes we can!

    But equally, there is SOME obligation to discuss
    prevention -- even though we know that most
    parents will reject it.

    Once a person is informed of the (below) facts,
    and STILL chooses the minus lens, then
    HE must consider that HE is personally
    responsible for the consequences that
    MUST ensue.

    Let us put responsibility where it really belongs.


    Best,

    Otis

    ******


    Monkey eyes grow into focus

    [Or, to say it another way, their focal status
    changes to match the applied minus lens as a
    natural "control system". Completely reasonable
    and expected. OSB]


    Josh Wallman

    Sally McFadden

    The strongest evidence for visual guidance of eye growth
    comes from experiments in which chicks wear positive or negative
    spectacle lenses that impose functional myopia or hyperopia on
    their eyes. These chicks compensate nearly perfectly for the
    lenses, so that after a week of wearing lenses their vision is
    functionally emmetropic again .

    Of course, if the lenses were removed, those eyes that had
    worn positive lenses would be very hyperopic and those that had
    worn negative lenses very myopic. Because negative lenses are
    universally prescribed for myopic children, one hopes that this
    compensation is a peculiarity of birds, and that one need not fear
    that giving myopic children spectacles would exacerbate their
    myopia.

    It is important to ask, therefore, whether this same
    compensation occurs in primates. In this issue of Nature
    Medicine, Hung et al. conclude that the answer is almost
    certainly YES:

    In their study, all but one of the monkey eyes made myopic by
    positive lenses shifted towards hyperopia (Fig. 1), and all but
    one of those made hyperopic by negative lenses shifted toward
    myopia.

    The amount of compensation was better with low-powered lenses
    than with the stronger lenses.

    Over the period that the monkeys wore the lenses over one
    eye, the eyes with hyperopia imposed by negative lenses became
    more myopic (negative values), while those with myopia imposed by
    positive lenses became more hyperopic (positive values). Neonatal
    eyes are generally hyperopic and normally change in the myopic
    direction (note the control animal that wore lenses without
    optical power (0 D).

    The findings of Hung et al also raise the concern that
    correcting emerging myopia may exacerbate myopic progression that
    would otherwise be self-limiting.

    The article is from Nature Medicine, Vol.1 Numer 8, August
    1995.
     
    Otis Brown, Jul 8, 2004
    #1
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  2. Otis Brown

    Dr Judy Guest

    You use the word "always". So if you had one example where using minus did
    not create more minus you would go away? We have already provided you with
    examples of this, both case reports and scientific studies.

    snip of summary of some research on emmetropization using high minus and
    high plus lenses to simulate congenital refractive error.
    No one has ever disagreed with you about emmetropization. Yes, when young
    animals have large refractive error simulated by the use of high plus or
    minus lenses, the eyes alter their growth rates so that the eye/lens system
    has refractive error approaching zero. We also know that this
    emmetropization process occurs in young humans up to about the age of four.
    Eye doctors have modified their approach to congential refractive error in
    children and now we do not prescribe corrective lenses for children under
    four unless refractive strabismus or amblyopia is present.

    However, this research has little to no relevance to correction of
    refractive error that develops later in life. Minus lenses are not used in
    excess of the refractive error of the eye. Myopes with correction have a
    lens/eye system with zero refractive error and therefore there is no
    stimulus to emmetropization that would cause myopia to increase.

    Furthermore, studies with myopes over the age of four using plus lenses on
    so that the lens/eye system has a net myopic refractive error and thus does
    create a stimulus to emmetropization that would cause myopia to decrease
    have found that, in fact, the myopia does not decrease and one study found
    that using plus actually caused the myopia to increase.

    Science does not support your ideas about using plus lenses to prevent
    myopia.

    Dr Judy
     
    Dr Judy, Jul 8, 2004
    #2
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  3. Otis Brown

    Otis Brown Guest

    Dear Judy,

    Subject: Pure science to determine if the natural
    (not defective) eye is dynamic.
    [Separate from ANY medical issue
    Simply a matter of objective measurement
    no "reading" into the experimental data
    something that is not there.]

    I respect the "second opinion", as I hope you will.

    A person has a right to expect a discussion of
    alternatives -- even difficult alternatives
    like true-prevention with a plus lens.

    Since you choose to stone-wall objective
    SCIENTIFIC experiments like the above,
    I think the issue comes down to the
    point where the person himself will
    have to look at this kind of data
    and make a PERSONAL decision about it.

    But we disagree on the concept of
    the "second opinion", and a patient's
    right to at least hear about it.

    Best,

    Otis
    Engineef


    ******
     
    Otis Brown, Jul 9, 2004
    #3
  4. Otis Brown

    Dr Judy Guest

    What experiment do you mean by "the above". Can you cite a published study
    using plus lens to reverse/prevent myopia or a published study showing
    myopia increase in human myopes caused by the use of minus lenses. I would
    like to read them, so far you have not provided any citations.

    Dr Judy
     
    Dr Judy, Jul 10, 2004
    #4
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