Scientific Proof that the Natural Eye is Dynamic -- not Passive

Discussion in 'Eye-Care' started by Otis Brown, Jul 28, 2004.

  1. Otis Brown

    Otis Brown Guest

    Dear Friends,

    Subject: A comparison of the predictions of two
    mathematical models with the experimental data --
    concerning the behavior of the natural eye.

    Here is an analysis of the natural eye's behavior when a
    "step-input" is applied to the system. The result is an expected
    "time-constant" response, indicating that the natural (not
    defective) eye behaves as a control-system -- by objective,
    scientific testing.

    The Google "text" compresses the graph in this paper. By
    down-loading the text into micro-soft word, or other
    word-processor, the proper perspective of the graph should be






    By Otis S. Brown

    Part of the art and skill of the engineer and of the
    experimental physicist is to create conditions in which certain
    events are sure to occur.

    Eugene Wigner


    Critical experiments are those experiments that allow us to
    choose between two major versions of factual truth. Without this
    check of physical reality, we can never determine the behavioral
    characteristic of the natural eye. The concept that the native
    eye is a rigid system is potentially a valid concept -- until we
    actually make measurements of the impact that a confined
    environment has refractive status of the natural eye. When we
    make the measurements, we find that the Helmholtz-passive theory
    is not accurate in accounting for the experimental data.


    The normal human and primate eye maintain a high degree of
    focal accuracy while major optical components change in an
    unpredictable manner. (1) The equation, developed from a dynamic
    model that is capable of accounting for this degree of accuracy,
    also predicts that the eye's refractive status will display a
    time-constant effect to a step-change in its visual environment.
    (2) (3) The predictions of this theory are compared on a
    qualitative and semi-quantitative basis with a Helmholtz-passive
    theory of the normal eye's behavior.


    While such a test cannot be carried out on human-primates,
    monkey-primates can be subjected to a step-change in their visual
    environment. (4) The following equation predicts the eye's focal
    status as a function of time:

    Focus = Offset + Accommodation + Delta * [1 - EXP( -t/TAU ) ]

    The required values are the average value of accommodation
    before and after the start of the test.

    The time-constant, TAU, has an approximate value of 100 days
    for pigtail macaque monkeys. The physiological offset is a
    measurable characteristic of the human and primate eye. It has an
    approximate value of +1.5 diopters. Further experiment and
    measurement will be required to establish greater accuracy for
    these fundamental constants of the natural eye's behavior.

    The average value of accommodation is determined by the
    visual environment of the eye. For instance, if a monkey is kept
    in a hooded visual environment of 20 inches, his environment will
    have a minimum value of -2 diopters. If he spends 50 percent of
    his time looking at 20 inches (-2 diopters), and the other 50
    percent of his time looking at 12 inches (-3.2 diopters), his
    average value of accommodation will be -2.6 diopters.
    Alternatively, if he spends 100 percent of his time looking at 15
    inches (- 2.6 Diopters), his visual environment will be -2.6

    By this technique of quantitative estimation, and by actual
    observational measurements, we can establish the average value of
    accommodation for monkeys kept in various visual environments.
    The following values are preliminary estimates:



    - 0.8 Diopters -1.8 Diopters - 2.6 Diopters

    If monkeys in a caged visual environment are placed in a
    hooded environment, their eyes will experience a step-change of:

    1.8 - 2.6 = - 0.8 Diopters

    Before the start of the test the focal status is: (At t = 0 )

    Focus = 1.5 + (-1.8) + (0) * [ 1 - EXP ( - 0 / 100 ) ]

    Focus = -0.3 Diopters

    After 294 days their focal status will be:

    Focus = 1.5 + (-1.8) + (-0.8) * [1 - EXP ( - 294 / 100 ) ]

    Focus = - 1.1 Diopters


    Dr. Young used Macaca Nemestrina (Pigtail) monkeys in his
    test. The monkeys were placed in a chair with their heads
    situated so their maximum visual distance was limited. The hoods
    were not more than 20 inches from the eyes of the monkeys at the
    furthest point, and averaged around 14 inches.

    Nine adolescent animals were selected and a control group was
    maintained. Their refractive status was measured at two week
    intervals. The experiment was continued for eleven months. The
    measured mean focal status for these monkeys is shown on the
    FORTRAN generated graph. Three monkeys were removed from the test
    after four months due to pregnancy and sickness.

    The refractive characteristics of the control group did not
    exhibit the time-constant effect demonstrated by the monkeys
    subjected to a step change in their visual environment. (Figure


    There are two fundamental theories of how the normal eye
    controls its focus while growing. One theory can be described as
    a Helmholtz-heredity theory of the eye's focal growth. This
    theory states that the cause of nearsightedness is purely genetic
    in origin, and asserts that the visual environment has no effect
    on the refractive state of the natural eye. This is a passive
    theory of the normal eye's behavior.

    For this experiment the prediction of this theory is that
    there should be no change in the refractive status of monkeys who
    experience a delta in their visual environment, since their
    genetic characteristic is not altered by the experimental
    situation. Alternatively, the prediction of this theory is that
    no difference in refractive status should develop between the
    normal eyes of the test group relative to the control group.

    A dynamic (feedback control) theory states that the eye
    continuously servos, or controls its refractive-status based on
    the eye's average value of accommodation. This theory predicts
    that there will be a time-constant response to a delta in the
    eye's value of accommodation.

    INTO BACK URED -1.1 -1.0 -.9 -.8 -.7 -.6 -.5 -.4 -.3 -.2 -.1
    TEST ...................................................
    0 -.33 -.33 <-----------------------------------<< M
    7 -.38 Accommodation Delta F H
    14 -.43 -.40 - 0.8 Diopters F M H
    21 -.48 F H
    28 -.53 -.48 F M H
    35 -.57 F H
    42 -.60 -.60 M H
    49 -.64 F H
    56 -.67 -.71 MF H
    63 -.70 Measured (M) F H
    70 -.73 -.78 Status >>---> M F H
    77 -.76 F H
    84 -.78 -.83 M F H
    91 -.81 F H
    98 -.83 -.87 M F H
    105 -.85 F H
    112 -.87 -.90 M F H
    119 -.89 F H
    126 -.90 -.95 M F H
    133 -.92 F H
    140 -.93 -1.00 M F H
    147 -.95 F Test Group (F) H
    154 -.96 -1.05 M F <-----<< Prediction H
    161 -.97 F H
    168 -.98 -1.10 M F H
    175 -.99 F H
    182 -1.00 -1.08 M F H
    189 -1.01 F H
    196 -1.02 -1.06 M F Control Group (H) H
    203 -1.02 F Prediction >>--------> H
    210 -1.03 -1.07 M F H
    217 -1.04 F H
    224 -1.04 -1.08 M F H
    231 -1.05 F H
    238 -1.06 -1.09 M F H
    245 -1.06 F H
    252 -1.07 -1.10 M F H
    259 -1.07 F H
    266 -1.07 -1.10 MF H
    273 -1.08 F H
    280 -1.08 -1.10 MF H
    287 -1.08 F H
    294 -1.09 -1.10 MF H
    -1.1 -1.0 -.9 -.8 -.7 -.6 -.5 -.4 -.3 -.2 -.1

    The best way to choose between these two competing theories
    is to compare their predictions on a qualitative and
    semi-quantitative basis. On a qualitative basis the dynamic
    theory predicts a net change in focal state of the test group
    relative to the control group. The passive theory predicts no
    change. The passive theory can not be put in a form which will
    yield quantitative predictions for the eye's refractive status as
    a function of time, and for that reason cannot be compared on a
    quantitative basis.


    The Laplace transfer function for the long-term focal control
    behavior of the normal eye is: (2)

    1 / (TAU s + 1 )

    The impulse (perturbation) time response of this function is: (5)

    Focus = Offset + Accommodation - Impulse * EXP (-t/TAU )

    This time-domain equation represents the basic underlying
    dynamic behavior characteristic of the natural eye when it is
    subjected to a sudden change in its accommodation status.


    If the estimated value of accommodation ( - .8 Diopters) for
    a population of wild monkeys is used in the impulse equation, the
    result is:

    Focus = 1.5 + ( -.8 ) - ( 0 ) * EXP ( - t / TAU )

    Focus = + 0.7 Diopters

    The plus indicates that the normal eyes of these monkeys have
    a normal (positive) focal state. The focal status of the normal
    eye (hyperopia) is measured with a plus lens. The measurement for
    the normal eye's focal status is made with the individual reading
    the eye chart at 20/20. Increasingly stronger positive lenses are
    placed in front of the eye until a lens strong enough to blur the
    20/20 line is obtained. This lens strength is the specific value
    for the refractive status of the natural eye.

    A positive focal state (sometimes called hyperopia) is the
    condition of the natural eye. If the eye is placed in a confined
    visual environment, the eye will gradually change its refractive
    status in a negative direction. When the native eye changes its
    focal state to a minus value the eye is said to be nearsighted.
    This result is observed in populations of Naval students. (6)


    Initially, the monkeys in this experiment were, on the
    average, slightly nearsighted. Their eyes were 20/25 at the start
    of the test and became more myopic (20/80) at the end of the test.
    Wild monkeys have 20/20 vision with an average refractive status
    of +0.7 diopters.


    (See Fortran graph for data.)

    Unexplained Variation = 0.07227
    Explained Variation = 1.23809
    Total Variation = 1.31037

    Correlation Coefficient = 0.97203

    This data, which represents the fundamental behavior
    characteristic of the natural eye, correlates with the equation:

    Focus = Offset + Accommodation + Delta * [1 - EXP(-t/TAU ) ]


    Was the correlation coefficient from this experiment
    accidental? Did Dr. Young randomly obtain 0.972 for the monkeys
    in the test when the actual population correlation coefficient was
    zero? This assertion can be checked by use of the students "t"

    t = ------------------------
    / 1 - r ^2
    \ / ---------
    \/ n - 2


    n = 23 (Number of measurements made)

    r = 0.97 (Correlation coefficient from the experiment)

    for v = 21 (Degrees of freedom = 23 - 2)

    t = 3.819 (Value for 99.9 percent confidence limit)

    t = 0.97 / SQRT [ ( 1 - 0.97 ^2) / ( 23 - 2 ) ]

    t = 18.28

    Since 18.28 exceeds 3.819 (the 99.9 percent confidence limit)
    we can reject the idea that the Helmholtz-passive concept is
    correct. There is a very high correlation between the average
    value of accommodation and the refractive status of the natural


    The Range of Possible Values for the Correlation Coefficient

    If the experiment is repeated 100 times, will we get the same
    correlation coefficient? What is the range of correlation
    coefficients that we can expect from the large population of
    normal eyed individuals?

    If from a bivariate population with a correlation
    coefficient, RHO, all samples of size n are taken, then:

    Z(r) - m (RHO)
    z = -----------------


    Z(r) = 0.5 * ln ( (1 + r) / (1 - r) )

    m(RHO) = 0.5 * ln ( (1 + RHO) / (1 - RHO) )

    Sigma = 1 / Square Root (n - 3)

    z = Abscissa for area under probability curve


    r = 0.97

    Z(r) = 2.092

    n = 23

    Sigma = 0.2236

    Z = +/- 2.58 for 99 percent confidence

    Area = 1.0 - 2 * ( 0.495 ) = .01

    By rearranging the equation:

    m(RHO) = Z(r) +/- (Sigma * z)

    using values: r = 0.97, n = 23, z = +/- 2.58

    m(RHO) = 2.092 +/- 0.57688

    Using look-up tables:

    m(RHO) = 2.6688 and therefore the upper limit for RHO is 0.99

    m(RHO) = 1.5151 and therefore the lower limit for RHO is 0.90

    In other words, given the results of this experiment, we can
    conclude that it is virtually certain that the large-scale
    population coefficient will lie between 0.90 and 0.99 for all
    primate eyes.

    There is a very high correlation between the natural eye's
    accommodation system and the focal state of the normal eye. The
    concept that the normal eye behaves as a (dynamic) neurological
    control system is strongly supported by direct factual data. The
    concept that the normal eye is passive in its behavioral
    characteristic is rejected by direct factual data.

    These statistical tests are standard and conclusively
    demonstrate the truth that the normal eye DOES NOT obey the
    Helmholtz-passive model for the natural eye's behavior. It is
    very unlikely that future experiments will support the
    Helmholtz-passive model of the normal eye's behavior.


    There are two powerful conceptual tools available for dealing
    with difficult servo problems -- analysis and synthesis. Since it
    is almost impossible to gain access to the accommodation system
    (that controls the eye's long-term focus), an indirect approach is
    required to establish the fundamental behavior characteristic of
    the normal human eye.

    An indirect approach results in the development of
    mathematical models. By constructing two reasonable physiological
    models for the natural eye's behavior, we can develop two sets of
    theoretical predictions. We can then decide, on the basis of
    direct experimentation, which model is more fully confirmed by the
    available experimental evidence.

    An analysis of the focal design requirements of the normal
    eye demonstrates that each eye must maintain a dynamic accuracy of
    better than 1.5 percent while growing to maintain normal vision.

    In synthesis, we develop a dynamic design which will account
    for the maximum number of facts known about the natural eye's
    focal setting action. Since the human body relies on feedback
    control principles in its design -- accommodation, temperature,
    and pH levels -- we find it appropriate to apply this concept to
    the eye's focal behavior. The opposite suggestion, that the
    normal eye ignores the accommodation signal while growing, leads
    to a theory that is incapable of accurate quantitative

    This analysis/synthesis approach points to an equation that
    accurately predicts the dynamic behavior of the human and primate
    eye. The equation can support a procedure that will be effective
    in preventing nearsightedness, if the eye's dynamic behavior is
    understood, and the preventative procedure is assiduously carried

    Accuracy and stability of the natural eye's behavior can be
    understood by modeling the eye as a servomechanism. An eye with
    this type of control system will exhibit a time-constant effect if
    subjected to a step-change in the eye's visual environment. In
    this experiment a "brute force" change was induced in the average
    visual environment. A time-constant response was measured in the
    eye's refractive status. The theory which is compared to this
    concept is a Helmholtz-passive theory of the eye's focal behavior.

    The dynamic analysis leads to a general equation for the
    long-term behavior of the normal eye. On the basis of this
    experiment we suggest that the dynamic (cybernetic) model is

    As with most mathematical models, certain effects (e.g.,
    noise and perturbations in the system) have not been included.
    These effects will be assessed and represented in later chapters.
    Our experience, however, indicates that this model is very
    accurate with respect to other dynamic tests that have established
    the normal eye's behavioral characteristic.

    In the absence of any other experimentally confirmed equation
    we can tentatively conclude that this test confirms the accuracy
    of this equation -- within the limits imposed by the experimental
    data that is available to us.


    PERSONS, (207-225) Progress in Ape Research (1977)

    2. Brown, O., Berger, R. A NEARSIGHTEDNESS COMPUTER, (343-346),
    The 7th Annual New England Bioengineering Conference (1979)

    GROWTH OF THE EYE, (133-136) The 8th Annual New England
    Bioengineering Conference (1980)

    PRIMATE EYE, American Journal of Ophthalmology, Vol. 52, No.
    5, Part II, November 1961

    TO FOCAL PERTURBATIONS, The 2nd Annual conference of the IEEE
    Engineering in Medicine and Biology Society (1980)

    STATES NAVAL ACADEMY, Archives of Ophthalmology Volume 25, #4
    (April 1941)
    Otis Brown, Jul 28, 2004
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  2. Otis Brown

    Otis Brown Guest

    Subject: The "corrupted" graph in this paper.

    Since the graph (Figure 1) is "compressed" I will
    describe it briefly.

    (If you type "reply" you see the graph with out
    correction -- for some reason.)

    From the study of control systems, we expect that the
    natural eye will exhibit a very basic response:

    1. Open loop. (i.e., no response at all)

    2. Closed-Loop (i.e., we are dealing with a sophisticated
    control system that controls its refractive
    status to its visual enviroment.)

    The first test confirms that a poplulation of
    natural or normal eyes behave as a control system.

    The second part is to confirm by direct measurement,
    the character of this control system, and the
    correlation of this data with the e ^ (t/tau)

    The experimental data is almost an exact
    duplicate of the e ^ (t/Tau) curve.

    You can see how close it is by checking the



    Otis Brown, Jul 29, 2004
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  3. Otis Brown

    Dr Judy Guest

    (Snip of description of FA Young experiment with confining monkeys 24/7 to a
    box for 8 months and the development of myopia in the monkeys)

    At one point you stated the snellen uncorrected vision of the monkeys; how
    was this measured? Did he teach the monkeys to read too? Some people think
    that literacy is the cause of myopia, maybe the box had nothing to do with
    the myopia, and it was due to the use of reading primers.

    Yes, we know that young animals eyes will tend to modify their growth so as
    to be close to emmetropic if congenital refractive error is present.
    Confinement of the monkeys simulated congenital hyperopia and, as expected,
    the eyes ended up close to emmetropic for that enviroment. This experiment
    does not prove that accommodation is the trigger for the emmetropization.
    Other experimentors have found that some species of monkeys show this effect
    and others don't, ie not all primate eyes behave in the same way. Other
    experimentors have found that using atropine or cutting the nerves serving
    accommodation does not prevent the myopia.

    Later experiments found that removing the monkeys from the confined
    environment for as little as two hours a day prevented the myopia,
    suggesting that the system somehow recognizes that accommodation at near is
    "ok" as long as part of the day is spent unaccommodated. In other words,
    the system can differentiate between congenital hyperopia which needs to be
    corrected via eye growth and lots of time spent looking a near, which should
    not be corrected via eye growth.

    Finally, if accommodation triggers eye growth and myopia, why are there
    hyperopes? About 75% of adult North Americans are hyperopic. They have
    spent their entire lives accommodating at all times and for all distances,
    just like Young's monkeys and yet they have not become myopic and have, in
    fact, not even altered eye length enough to cancel the hyperopia.

    Any hypothesis about myopia must account for all the data and known facts,
    not just account for the results of one experiment.

    Dr Judy
    Dr Judy, Jul 29, 2004
  4. Otis Brown

    Otis Brown Guest

    Dear Judy,

    Subject: It takes some common sense.

    Monkeys are measured with a paralyzing drug.

    The goal was to show that the refractive state
    of the natural eye followed an e ^ (t / Tau) function.

    You can not measure the Snellen on the monkeys, but
    you can be reaonably clear about their VA.

    Any intelligent discussion with informed engineers
    and pilots will bring this out.

    But of course you love to play "dumb", and are
    quite good at it.

    The rest of your commentary I will pass on
    to our "interested parties".

    Thanks for your commentary.



    Otis Brown, Jul 30, 2004
  5. Otis Brown

    Guest Guest

    And wich eye, the human or the animal?
    Provide data that it does in humans Otis, otherwise it is called by Mike
    ''mental mastrubation''
    Again your big mistake Otis, jumbling VA and ametropia.
    Than show it, instead of mentioning.

    Oh, how terrible, I used the word ''it'', excuses Otis.
    Who is using a Snellen chart on monkeys?
    You are a bad loser Otis and yes I might think DrJudy is quit good in
    showing you are wrong and she does show it in an intelligent and
    understandable way.
    Yes, your aunt Mary and uncle Bernie is it not Otis?
    Can we get there answers on your postings?
    My pleasure

    Jan (normally Dutch spoken)
    Guest, Jul 30, 2004
  6. Otis Brown

    Otis Brown Guest

    Dear Jan,

    Subject: ODs who have gone "Rishi" on the subject.

    Re: When a person is on the losing side of a
    scientific argument -- they start calling
    people "names". Mark my words well!

    Interesting choice of words. Maybe that is what you are doing
    in your closed society, that only talks to itself.
    I can think of similar words for a "circle", but
    unlike you -- I won't use them.

    I had hoped for a "high level" and honest discussion
    about the scientific attributes of the natural eye
    as a sophisticated control system.

    Obviously you have no interest in such intellectual
    persute of scientific truth, and your words
    are a profound indication of that "professional

    There are other true-professional ODs, who apprecite
    the difficulty of prevention, and for their sake,
    I simply will not respond in kind.

    But you can bet that your statment will go out
    to them, so that they might understand how
    rediculus and none-professional you really
    are. Up to now, I would have though better
    of you.

    Further, when we present our work to
    pilots at Embry-Riddle, you statement
    will be part of that presentation.




    cc: True professionals in all walks of life.


    Otis Brown, Jul 30, 2004
  7. Otis Brown

    andrew Judd Guest

    There is a certain reality here.

    Although Jan, (is this short for Janet?), somewhat predictably plays
    the fool and is hell bent on abusing whoever takes his fancy, Otis is
    truelly an idiot amongst his peers.

    Poor old Rishi, who kind of speaks a certain truth, and yet is insane,
    tends to regard Otis as 'his Idiotis'

    Lets be fair here. For an Italian, who is more or less a complete
    nutcase, Rishi calls a spade a spade and has a certain genious for the
    apt phrase.

    Everybody else seems to be in the kindergarten of insanity, is it not

    Some people like to be known as 'Doctors' Dr Greg, Dr Judy, and Dr
    Leukoma quickly arise to some part of my body.

    Me? I tend to find it hard to produce paragraphs correctly, sometimes
    tend to drink too much, lack the kind of quality attention I really
    think I deserve, and need to have a reasonable amount of penis vaginal
    sex rather than all this crap anal masturbation that is the norm here.
    andrew Judd, Jul 30, 2004
  8. Otis Brown

    Guest Guest

    I'm waiting Otis...........

    I'm also waiting for proof of your pluslens idea in preventing myopia in
    humans, let's see what comes first.

    Than show yours Otis speaking of "high level" in this oneway discussion.
    Honesty yes, but then you have to respect the arguments against your idea
    and refute them in a proper way.
    I'm interested in a professional way, until now I did not see any proof or
    answers from you wich I may consider ''professional''
    BTW, is showing some calculations a sign of having intellect or just a trick
    to impres people overhere?
    I'm not impressed Otis that's for sure.
    I do not say you are not an intellectual, the only difficulty for me is how
    to regognize you are one?
    Who says I do not?
    May I have the pleasure to meet them in this newsgroup?
    So fare non of these backed you up here.
    How come?
    Yes and as usual out off context I suppose Otis?

    Jan (normally Dutch spoken)
    Guest, Jul 30, 2004
  9. Otis Brown

    Otis Brown Guest

    Dear Jan,

    Subject: Keeping a technical discussion about the
    dynamic behavior of the natural eye "civil".

    Since you do not understand control system, and
    their signature behavior characteristic, I understand
    your "gut" reaction to call technical analysis,
    "intellectual masterbation".

    A profoundly stupid remark. I though better
    of you -- up to that point.

    If that is the "attitude" of you, and the
    other ODs on this site, then I would
    say that would be a very strong reason
    to have you NOT BE PART of a study,
    whey you make that kind of remark.

    I can work with others -- who keep
    and open mind -- but that reflects
    that "god like" attitude, they your
    are perfect about evertying -- even
    subject matter where you have
    no meanigful training or experience.

    No -- I could not work with you
    under any circumstance.



    cc: For our engineering review group.

    Otis Brown, Jul 31, 2004
  10. Otis Brown

    Guest Guest

    Again, no sign of data on the request placed here several times by different
    individuals to prove your (Otis) pluslens idea in preventing youngsters to
    became myopic, works.
    The normal procedure when you (Otis) respond.
    Read my lips, you (Otis) start another thread and starts from the beginning
    like a never ending circle.
    May I receive civil answers from your side Otis, instead of a bunch of
    May I ask to quote me correctly Otis?

    If you quote then quote correctly Otis, I was refering to a statement made
    by a proffessor of Mike who used the phrase "mental masturbation"
    Quit a difference if I may say.

    major snip........
    Who says I want to?

    Jan (normally Dutch spoken)
    Guest, Jul 31, 2004
  11. Otis Brown

    Otis Brown Guest

    Dear Jan,

    Subject: Scientific-engineering study at Embry-Riddle for prevention.

    An engineer who wishes to understand that the natural eye is
    dynamic, but be conversant with the experimental data that
    proves that the NATURAL EYE is a control system (closed-loop)
    and not a "heredity" (open-loop) system.

    Where the pilot-engineer review these experiments, and
    is prepared to make a commitment to a engineering study
    then I feel confident that we can produce data
    that shows that the null-hypothesis (the open-loop theory)
    is a failure.

    But of course, it takes time to organize that type of
    approach. But we stand ready to do it -- given the
    opportunity to do so.

    See, "Aeronautical College" on

    As well as the statistical analysis to support
    this ENGINEERING (not medical) study of the
    dynamic behavior of all NATURAL EYES.



    Otis Brown, Jul 31, 2004
  12. Otis Brown

    Dr. Leukoma Guest

    Saying that the eye is dynamic rather than passive is certainly not a
    revelation to any visual scientist or ophthalmic professional. This is
    like stating that the earth is round instead of flat. The devil is in the

    Dr. Leukoma, Jul 31, 2004
  13. Otis Brown

    Dr Judy Guest

    Yes, you can measure refractive error objectively, how do you measure monkey
    VA, which is subjective.
    No you can't, it is not possible to state what uncorrected VA is based on
    refractive error.
    You still have not answered my question: Why do hyperopes exist?

    Dr Judy
    Dr Judy, Jul 31, 2004
  14. Otis Brown

    Cathy Hopson Guest

    Sorry to bug you again. Doesn't confinement simulate near work as well as
    congenital hyperopia? If it was expected from either cause that the eyes
    will end up emmetropic for a given environment, an emmetropic result doesn't
    help or hurt either argument. In the later experiments, where removal from
    confinement for two hours/day prevented myopia, you saw that eye growth
    stopped, so deduced it must be related to congenital hyperopia (where eye
    growth is supposed to be the adjustment mechanism) rather than related to
    accommodation (where the ciliary muscle is supposed to be the adjustment
    mechanism). What, then, explains the emmetropization results in the earlier
    confined-with-no-time-off experiments? How do we differentiate there? Had
    the eyes stopped growing when congenital hyperopia was resolved, but the
    ciliary got stuck in near-mode? If eye growth had continued in the earlier
    experiments, all we've learned by this comparison of the two experiments is
    that two hours/day unconfined is needed to prevent the myopia trigger from
    being set off. How do we know whether the trigger sent the eye straight to
    elongation or elongated the eye at the behest of an overtired ciliary?

    Finally, to answer the question, hyperope's exist because they get enough
    time unconfined.

    Cathy Hopson, Aug 2, 2004
  15. Otis Brown

    Otis Brown Guest

    Dear Cathy,

    Re:> Finally, to answer the question, hyperope's exist because they get enough
    A couple of clarifications. The natural eye, kept in an
    "open pen" environemt will have a range of refractive states
    running from zero to +2.0 diopters. It would be a
    mistake to call them all "defective" or in a state of "error"
    due to a bad theory. I would avoid the use of the work
    "refractive error" or "hyperopia" to describe refractive
    states that are completely normal.

    You are correct about primates kept in an open environment.

    Dr. Francis Young measured the refractive status of a
    population of primates (375 I believe).

    There refractive status had a normal curve as described

    It would be a tragic mis-use of the English language
    to describe normal refractive status as an "error"
    or defect. Yet that is how the "traditional" theory
    describes all eyes. Bad theory.



    Otis Brown, Aug 7, 2004
  16. Otis Brown

    Guest Guest

    Otis, the second Gullstrand ?

    Allvar Gullstrand
    In 1911 he received the Nobel Prize for Physiology or Medicine for his work
    on the dioptric apparatus of the eye performed jointly with Moritz von Rohr,
    with which they placed the correction of refractive errors in the eye by
    means of eyeglasses on a strictly scientific basis.

    He and others NEVER used the word ''defective''

    Cathy, maybe you want to read what Allvar Gullstrand scientificaly did for
    both the ophthalmology and ophthalmic optics.

    Again Otis, you, and you alone, use the word ''defect'' or ''defective''
    Again and again you quote incorrect Otis.
    A very bad habit.
    You are a tragic Otis, the way you are mis-using this scientificaly

    Jan (normally Dutch spoken)
    Guest, Aug 7, 2004
  17. Otis Brown

    Otis Brown Guest

    <Jan> wrote in message

    Subject: Freezing the eye to do "optical analysis".

    Yes, Jan, what was done by Allvar Gullstrand was to
    carry forward the assumptions made by J. Kepler.

    If you ASSUME that the eye is a pure optical bench
    THEN you can calculate the various parameters
    of the "idealized" eye to 4 or 5 significant figures.

    That is the analysis -- an never reproduces the
    behavior of the natura eye.

    This is the effect of a "box-camera" paradigm.

    I have read Gullistrand's "schematic model" and
    he is careful to point out that this is
    only a model -- obviously based on assumptions
    that have not proven to be true.

    You keep on insisting that a minus lens has
    NO EFFECT on an entire population of natural
    eye -- and I keep on testing your assumption
    and find out that all natural eyes MOVE NEGATIVE
    (the entire population) when a minus lens
    is placed on them.

    This is "systems" testing, with accurate data
    that was not available when Gullistrand created
    his "idealized" model of the eye.

    It is about time we correct this misunderstanding.

    That is the nature of our argument.


    Otis Brown, Aug 7, 2004
  18. Otis Brown

    Otis Brown Guest

    Dear Mike,

    You have a bad habit of totally ignoring scientific
    proof that the natural eye "moves negative" when
    you place a minus lens on it.

    The same is true when you apply a "step input"
    change of "visual environment" of -0.8 diopters,
    and the refractive status of the natural eye
    (entire population) of the natural eye
    moves negative, following the e ^ (- t/ Tau)

    You are completely blind about objective,
    scientific (not medical) proof that
    the natural eye is a dynamic system, where
    the reafractive state of the fundamental
    eye "follows" the accommodation SIGNAL.

    But, I do agree that true-prevention is
    difficult, but I believe possible,
    if the person concerned with the
    issue is prepared to:

    1. Verify that his vision passes
    the LEGAL requirement (Snellen-DMV)

    2. Willing to accept the much more
    difficult work of "pushing hard" with
    the use of the plus -- and will
    verify 20/20. No guarantees -- but
    it does represent a "fighting chance"
    for the person (or pilot) who will
    "work" the issues.

    In fact I care deeply, for the issue of prevention,
    and people who have been prescribed a -1.5 diopter lens.

    I care deeply that they reject the excessive prescription
    of a lens of that strength -- and the consequences of
    wearing it all the time. This same idea has
    been experessed by Dr. Jacob Liberman, in his
    book, "Throw away you glasses and see". So
    for you to suggest that wearing a strong minus lens
    is even "wise" is completely unreasonable.



    cc: Interested parties.
    Otis Brown, Aug 8, 2004
  19. Otis Brown

    Guest Guest

    Major snip in a bunch off repeating blabla

    The usual respons of Otis, ignoring what is asked for and starting his usual
    Indeed a bad habit Otis, but your's and not Mike's

    Jan (normally Dutch spoken)
    Guest, Aug 8, 2004
  20. Otis Brown

    Otis Brown Guest

    Dear Mike,

    You seem to miss the point that PREVENTION means
    wearing a plus lens BEFORE the person is "myopic".

    This means that you do not wait UNTIL after the
    person is -10 diopters myopic. The action must
    be taken BEFORE his eyes FAIL the 1.8 cm letters
    at 6 meters, i.e., the person must take care
    to ALWAYS PASS the legal requirements for vision.

    Since Dr. Jacob Raphaelson spelled this out in
    his books, it was clear that responsibility
    to do this work correctly must depend on
    the qualities of motivation and persistance
    of the person concerned with the issue.

    He also must understand that when he sees
    "blur" out there he must get very busy
    and persistent in the us of a strong
    plus, and personally verify that he clears
    his vision to the required legal statndard.

    The result of personally doing this work is
    that he always passes the Snellen-DMV test,
    and NEVER shows up in your office.

    It is the education and motivation of the
    person himself that makes the difference.

    Thus "prevention" of this nature would be
    possible with a highly motivated person
    who is part of a scientific effort
    to PREVENT nearsightedness in the first
    place. A higher, but more difficult

    Hope you understand this isssue.




    cc: The interested parties.
    Otis Brown, Aug 9, 2004
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