Scientists state that pseudo-myopia leads to axial myopia.

Discussion in 'Optometry Archives' started by otisbrown, Dec 22, 2006.

  1. otisbrown

    otisbrown Guest

    Dear Prevention-minded freinds,

    There are two opinions about the prevention of myopia:

    The second-opinion, that on the threshold, if you could prevent
    incipient myopia before a minus lens is applied, you could
    prevent axial-myopia. Or, prevention is always impossible.

    Here is an analysis provided by Alex Eulenberg for
    your interest.


    Vision scientists George Hung (Rutgers Dept. of Biomedical
    Engineering) and Kenneth Ciuffreda (SUNY College of Optometry) are
    claiming that the "temporary" blurry distant vision that comes from
    reading too long, too hard, is a step on the way to permanent myopia.

    This may seem obvious to many of us, but then again, there are many in
    the eye care profession who would deny this, or at least express the
    opinion that there is room for doubt.

    The article is "Incremental retinal-defocus theory of myopia
    development-Schematic analysis and computer simulation" (in press)\
    "In addition, the theory has been able to explain how repeated cycles
    of nearwork-induced transient myopia leads to repeated periods of
    decreased retinal-image defocus, whose cumulative effect over an
    extended period of time results in an increase in axial growth that
    leads to permanent myopia."

    I must admit, since I have not read the article, that I am at a loss
    as to what these two mean by "decreased retinal-image defocus," but it
    is of little matter. What is striking here is the confidence in the
    way the authors present their theory. These are two prominent vision
    scientists and co-authors of a vision science textbook ("Models of the
    Visual System"). They are staking their reputations on the existence
    of a causal chain from near work to temporary myopia to permanent
    myopia. No "may lead" or "could result" here. I think this is a
    significant moment in the history of vision science.

    otisbrown, Dec 22, 2006
  2. otisbrown

    Neil Brooks Guest

    Otis's and everybody else's.
    Gee, Otis. A theory. How marvelous.

    YOU, too, have a theory. Unfortunately, it fails to hold up in HUMAN
    clinical trials AND it induces DOUBLE VISION in people naive enough to
    listen to you.

    Let's go back ... once again ... to Scientific Method 101 for Dummies
    like yourself:

    Recognize the problem

    Observe the problem

    Formulate a hypothesis (this is as far as you've ever gotten)

    Devise and conduct experiments to test the hypothesis (using the
    results of this testing to inform and revise your hypothesis. You
    seem to detest this part)

    Come to a conclusion based on the testing.

    Hurting unsuspecting people (or the children of desperate parents),
    helping nobody (ask your myopic niece), mangling statistics, and
    occasionally throwing out Greek letters doesn't make you a scientist.

    Not even close.
    Neil Brooks, Dec 22, 2006
  3. otisbrown

    otisbrown Guest

    otisbrown, Dec 22, 2006
  4. otisbrown

    Neil Brooks Guest

    Never let the facts get in the way of a good story, Otis.

    Why don't you make THAT your permanent Usenet signature?
    Neil Brooks, Dec 22, 2006
  5. otisbrown

    p.clarkii Guest

    Who friggin' cares! do you think that statement is some kind of
    credential that builds credibility? that website is a bunch of
    "alternative medicine" freaks (and thats being kind) who believe all
    sorts of wacky unproven notions.
    p.clarkii, Dec 22, 2006
  6. otisbrown

    Dr. Leukoma Guest

    Now that Otis has discovered this article by Hung and Ciuffreda, I am
    eager to see where he goes with it. I must say that quoting Alex
    Eulenberg -- who himself has not read the article, is not a very
    encouraging sign.

    Otis and Alex have now taken hold of the proverbial rope. Let's see
    just how long it will take them to hang themselves with it.

    DrG (who has read the entire article)
    Dr. Leukoma, Dec 22, 2006
  7. otisbrown

    Dr. Leukoma Guest

    Well, I'm waiting for Otis to read the study so he can tell us just how
    it supports his paradigm. This should be good.

    Dr. Leukoma, Dec 22, 2006
  8. otisbrown

    otisbrown Guest

    Dear Prevention minded friends,

    Subject: Professor Hung's theory -- simplified.

    In order to understand this "de-focus" theory, you
    should review the animation of it produced
    by Dr. Wildsoet on:

    What the theory predicts is that if you place
    a -3 diopter lens on the eye, it will change its
    refractive STATE by -2 diopters in six months.

    [See the refractive change on the blue-tinted
    eye on this site.]

    Here is Dr. Hung's verbal description of that proven
    process the eye uses to control its refractive STATE.




    A unifying theory of refractive error development.

    Hung GK, Ciuffreda KJ.

    Department of Biomedical Engineering, Rutgers University, 617
    Bowser Road, Piscataway, NJ 08854-8014, USA.

    While retinal defocus is believed to be myopigenic in nature,
    the underlying mechanism has remained elusive.

    We recently constructed a theory of refractive error
    development to investigate its fundamental properties. Our
    Incremental Retinal-Defocus Theory is based on the principle that
    the change in retinal-defocus magnitude during an increment of
    genetically-programmed ocular growth provides the requisite sign
    for the appropriate alteration in subsequent
    environmentally-induced ocular growth.

    This theory was tested under five experimental conditions:
    lenses, diffusers, occlusion, crystalline lens removal, and
    prolonged nearwork.

    Predictions of the theory were consistent with previous
    animal and human experimental findings. In addition, simulations
    using a MATLAB/SIMULINK model supported our theory by
    demonstrating quantitatively the appropriate directional changes
    in ocular growth rate. Thus, our Incremental Retinal-Defocus
    Theory provides a simple and logical unifying concept underlying
    the mechanism for the development of refractive error.

    PMID: 11127515 [PubMed - indexed for MEDLINE]


    Incremental retinal-defocus theory of myopia
    development-Schematic analysis and computer simulation.

    Hung GK, Ciuffreda KJ.

    Department of Biomedical Engineering, Rutgers University,
    Piscataway, NJ 08854, USA.

    Previous theories of myopia development involved subtle and
    complex processes such as the sensing and analyzing of chromatic
    aberration, spherical aberration, spatial gradient of blur, or
    spatial frequency content of the retinal image, but they have not
    been able to explain satisfactorily the diverse experimental
    results reported in the literature.

    On the other hand, our newly proposed incremental
    retinal-defocus theory (IRDT) has been able to explain all of
    these results. This theory is based on a relatively simple and
    direct mechanism for the regulation of ocular growth.

    It states that a time-averaged decrease in retinal-image
    defocus area decreases the rate of release of retinal
    neuromodulators, which decreases the rate of retinal proteoglycan
    synthesis with an associated decrease in scleral structural

    This increases the rate of scleral growth, and in turn the
    eye's axial length, which leads to myopia.

    Our schematic analysis has provided a clear explanation for
    the eye's ability to grow in the appropriate direction under a
    wide range of experimental conditions. In addition, the theory
    has been able to explain how repeated cycles of nearwork-induced
    transient myopia leads to repeated periods of decreased
    retinal-image defocus, whose cumulative effect over an extended
    period of time results in an increase in axial growth that leads
    to permanent myopia.

    Thus, this unifying theory forms the basis for understanding
    the underlying retinal and scleral mechanisms of myopia

    PMID: 17150204 [PubMed - as supplied by publisher]

    otisbrown, Dec 22, 2006
  9. otisbrown

    Dr. Leukoma Guest

    No it doesn't. You didn't read the paper. The abstract is misleading.
    Read the paper before you start, because when you do, you will be
    embarrassed that you wrote the above.

    Dr. Leukoma, Dec 22, 2006
  10. I seem to recall trying to lead him through one of Cuiffreda's models
    Scott Seidman, Dec 22, 2006
  11. otisbrown

    otisbrown Guest


    Subject: The Effects of "Corrective" Lenses: Insight and
    Comment From Eye Doctors

    Mike> If the theory predicts it, and it doesn't happen, what does that

    Mike, it means your believe that the natural eye is NOT dynamic,
    and that a minus lens has NO EFFECT on the refractive STATE
    of all natural eye -- against the objective scientific facts. And that
    is your majority-opinion.

    The second-opinion recognizes the fact that no clinical or
    statistical studies have ever demonstrated the
    long-term safety of a (minus) "corrective" lens.

    In fact, a certain percentage of doctors believe that -- as the
    second-opinion -- "corrective" lenses (also known as
    "compensatory" negative lenses) usually create dependency and
    make the eyes move more rapidly in a negative refractive direction.

    These concerns have been voiced in the professional
    literature by concerned doctors who support the concept
    the "second opinion" to do work for the prevention of nearsightedness
    with a plus lens.

    Here are sample excerpts from the professional literature voicing
    concerns about the safety of "corrective" lenses:


    "The use of compensatory lenses to treat or neutralize the
    symptoms does not correct the problem. The current education and
    training of eye care practitioners discourages preventive and
    remedial treatment." R.L. Gottlieb, Journal of Optometry and
    Visual Development, 13(1):3-27, 1982.

    "The emphasis on compensatory lenses has posed a problem for
    many years in our examinations. These lenses do not correct
    anything and may not serve the patient in his best interests over
    a period of time." CJ. Forkiortis, OEP Curriculum, 53:1, 1980

    "There are frequently ignored patterns of addiction to minus
    lenses. The typical prescription tends to overpower and fatigue
    the visual system and what is often a transitory condition becomes
    a lifelong situation which is likely to deteriorate with time." S.
    Gallop, Journal of Behavioral Optometry, 5(5):115-120, 1994

    "Single-vision minus lenses for full-time use produce
    accommodative insufficiency associated with additional symptoms
    until the patient gets used to the lens. This is usually
    accompanied by a further increase in myopia and the cycle begins
    anew." M.H. Birnbaum, Review of Optometry, 110(21): 23-29, 1973.

    "Minus lenses are the most common approach, yet the least
    likely to prevent further myopic progression. Unfortunately, they
    increase the near-point stress that is associated with
    progression." B. May, OEP Publications, A- 112, 1984.

    It seems that Professor Hung's concept of the dynamic
    eye is closer to scientific truth that your "belief" that
    the eye does not respond to an applied -3 diopter lens.
    (Over-prescribed if you like). And even the safety
    of that minus is an open question at this point.


    otisbrown, Dec 23, 2006
  12. otisbrown

    p.clarkii Guest

    Dr. Tyner is simply stating his observations that his patients who wear
    -3.00 D lenses do not progress to -5.00 myopes. i must corroborate
    that MY -3.00D myopes also do not progress in that fashion. that does
    not mean we choose to believe one theory or another theory, it is
    simply a statement of our observations on our patients. if your theory
    is correct, then why don't our patients behave as your theory predicts
    (hint: your theory could be incorrect).
    there is no such thing as your term "second-opinion". this is a phrase
    YOU choose to use to describe your personal believe and it is not
    supported by any evidence. you like to try to give your notions some
    credibility by claiming there is a larger group of others who also
    concur with you. sorry-- "second-opinion" = Otis' personal opinion and
    nothing more. you are just a lonely newsgroup internet troll.
    have you noticed that your supporting articles are from 20-30 years
    ago? indeed some real legitimate researchers considered this theory as
    plausible in the past but then something called the "scientific method"
    was used to examine it and it didn't hold up to testing.

    why haven't you moved on like the rest of the legitimate vision
    researchers did?

    do you believe the earth is flat?

    while you are at best illogical and at worst psychologically ill, you
    are indeed persistent!
    p.clarkii, Dec 23, 2006
  13. otisbrown

    Dr. Leukoma Guest

    This is a dynamite paper, by the way, and should appeal to any person
    who calls himself an engineer. Unfortunately for Otis, it won't
    support most of his ideas, especially as it pertains to the use of
    strong plus for the prevention of myopia. In fact, it puts Otis into
    an even tighter corner.

    Remember how we have been discussing the concept of retinal defocus as
    opposed to accommodation, and how Otis keeps dragging us back to the
    junkheap of outdated ideas? This paper makes that even more obvious.

    Dr. Leukoma, Dec 23, 2006
  14. otisbrown

    Dan Abel Guest

    Otis won't be embarrassed. He posts the most ridiculous things without
    Dan Abel, Dec 23, 2006
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