Who is the "layman"?

Discussion in 'Optometry Archives' started by Otis Brown, Jun 30, 2004.

  1. Otis Brown

    Otis Brown Guest

    Dear Friends,

    Subject: Disagreement about the dynamic
    nature of the fundamental eye.

    Jan accuses me of being a "Charlatan". Based
    on his bias -- and lack of understanding of the
    facts.

    I have not called him "names" but he feels free
    to engage in this type of personal denigration.

    I have always been accurate in describing the
    behavior of the natural eye as dynamic. Jan
    should produce evidence that the natural eye
    IS NOT DYNAMIC. He as yet to do so.

    Calling people "names" is not how you solve
    technical problems.

    "Charlatan" always implies the "exchange of money", as well
    as "medical" in some manner. I have made it absolutely clear that
    I am taking about the dynamic nature of the fundamental eye --
    which can have a positive or negative refractive state of 1/2
    diopter -- and still be normal. It would be difficult for anyone
    to construe this discussion as a pure-medical discussion.

    The problem that we interleave pure-science in with medicine,
    that we can not separate them. At least we should make an
    attempt. I am certainly NEVER attempting to "practice medicine"
    in any sense of the word. I expect the individual himself to be
    able to sort out what objective facts prove that the natural eye
    behaves as a auto-focused camera, from a traditional methods (that
    works) but creates serious secondary effects.

    Only the mis-understanding of the meaning of words could get a
    person to believe that I am talking about a "defective" eye.

    I expect that the person I talk to has some ability at
    "abstract thought", and this is the nature of the discussion.

    Under the above circumstance the only thing you could accuse
    me of is "technical inaccuracy" with respect to the experimental
    data -- as it concerns the dynamic behavior of the natural eye.

    Since people like Jan have refused to answer intelligent
    question post to him concerning this issues of DIRECT
    experimental measurement I am at a loss to argue the issue. I
    simply suggest that the intelligent engineer run the replant
    experiments and DECIDE FOR HIMSELF whether the natural eye is
    dynamic -- as we expect to be.

    In any event, here are Jan's arguments for your reading
    pleasure.

    Best,

    Otis

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

    Subject: Children Get Glasses They Don't Need?

    Dear Jan,

    Jan, we can call each other "names" if you like. What good
    does that do? A man on the "losing end" of an argument is likely
    to resort to that approach.

    If the subject is atomic physics, then you my friend are the
    "lay man".

    If the subject is organic failure of the eye, i.e., detached
    retina, the ophthalmologist is the expert and you are the "layman"
    as am I.

    If you use the term "error" to describe your profession, and
    your interoperations of the refractive state of the eye, then on
    that narrow grounds you can call yourself an "expert" and myself a
    "layman".

    Equally, I point to other ODs who do not agree with you at
    all. To express only one point-of-view, and call other experts --
    even in your field -- "charlatans" simply indicates the narrowness
    of your own mind.

    But if we are talking about the dynamic behavior of the
    natural eye, as a sophisticated system, (engineering) then you, my
    friend are a "layman".

    But I will post your statement to Dr. Steve Leung for his
    enjoyment, and others who have a more educated and technical mind
    on the subject of the natural eye's proven behavior characteristic
    -- as an auto-focused camera.

    Best,

    Otis

    cc Steve Leung


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


    "Otis Brown" <> schreef in bericht


    Otis> The proof is more for the person who is willing to reject
    your notion that a minus lens has NO EFFECT on the
    refractive status of the eye -- and appreciate what the
    factual data actually DOES TELL US about the behavior of the
    natural eye.

    Jan > Again walking around in circles Otis. You may use the term
    "factual data" but again you "forget" the show up with
    (f)actual data which tells me you are incompetent in this
    field of eye CARE. Please shut up or deliver proof and let
    me keep my mouth shut.

    Otis> For the ODs who would practice this PREVENTIVE approach -- I
    give my TOTAL SUPPORT.

    Jan > How nice.

    Otis> For the parent who will accept the use of the plus -- at the
    critical zero-diopters stage -- I also give very strong
    support.

    Jan > How nice of you.

    Otis> But the real responsibility must rest with the parent, to
    sort out these two contradictory methods (i.e., the second
    opinion).

    Jan > A second opinion normally is given by a specialist of at
    least the same caliber as the specialist who has given the
    first. You are not an eye-care-professional, Otis. You
    have no knowledge in this field.

    Otis> No one can arbitrarily use EITHER method until he first
    consults the parent (respects their intelligence) about this
    issue.

    Otis> Tragically, that "respect" for intelligent choice by the
    parent is almost completely lacking in your profession at
    this time.

    Otis> I do not care which method is used -- only that the parent
    has the education to understand the alternative, and more
    importantly, the reasons for and the necessity of using the
    preventive method.

    Otis> This issue of proof must rest more for the parents
    understanding of the issues involved.

    Otis> This is what you dis-respect in the person who walks into
    your office.

    Jan > The language of a charlatan. Also the language used by
    persons who do not have to respect the needs to solve a
    (vision) problems. Also the language of persons who don't
    have to take responsibility for his advice.

    Jan (normally Dutch spoken)
     
    Otis Brown, Jun 30, 2004
    #1
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  2. Otis Brown

    Dr. Leukoma Guest

    (Otis Brown) wrote in
    The fact that that some verterbrate eyes, including humans, undergo a
    process known as emmetropization is not news to eye doctors or visual
    scientists. I see you have yet to stumble onto it, though.
    The terms "dynamic nature" and "fundamental eye" have no meaning, and you
    have avoided defining them. That's your problem.
    We live in an age where science makes its way into medicine in the form of
    evidence-based medicine. I'm not sure what paradigm you are operating
    under, but it surely is not evidence based. You have presented no
    evidence. Put up.
    You have made a career out of obfuscation. Be clear man, or be silent.
    You are not proferring "abstract thought" so much as concrete treatment.
    Successful treatment does not necessarily arise from abstract thought, but
    from abstract thought put under the scrutiny of reproducible
    experimentation. You need to catch up to the 21st century.
    Since all you have offered are abstract thought experiments, I can fault
    you there as well.
    But, you have not posed intelligent questions. All you do is muck around
    in the quagmire of loose and imprecise language.
    Best,

    DrG
     
    Dr. Leukoma, Jun 30, 2004
    #2
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  3. Otis Brown

    LarryDoc Guest

    Excellent post, Dr. G!

    You make it absolutely clear, exactly, that Otis has absolutely nothing
    to say that is understandable or relevant to the rest of us who live on
    planet Earth in the 21st century.

    No proof.
    No definable logic.

    And your last line says it all so well.....
    It's over for you, Otis. Checkmate. Now go.

    Best,

    LB
     
    LarryDoc, Jun 30, 2004
    #3
  4. Otis Brown

    Dan Abel Guest

    Not to mention "charlatan". It doesn't always imply money, or refer to
    medical things. From my online dictionary:


    char€la€tan (shär2lú-tún) n. 1. A person who makes elaborate, fraudulent,
    and often voluble claims to skill or knowledge; a quack or fraud.
     
    Dan Abel, Jun 30, 2004
    #4
  5. Otis Brown

    Otis Brown Guest

    Dear Dan,

    Since you post yourself as an "academic" I presume
    you should be able to answer some basic questions
    about the natural eyes behavior -- and a
    mathematical model that represents that behavior.

    Rather that blathering on about "quack" and the like,
    why not act like a professional and answer the
    questions?

    Unless you would like to assert (without scientific
    proof) that a minus lens has NO EFFECT on the
    refractive status OF THE NATURAL EYE.

    Don't be a wimp -- answer the questions.

    Best,

    Otis
    Engineer






    JonEq5.txt

    Jon Neumann
    Physicist

    Dear Jon,


    "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

    Subject: Four questions to clarify the behavior of the natural
    eye under explicit scientific testing conditions.


    You asked me to define our audience. I would suggest the
    following.

    I will talk to an individual pilot personally, and expect him
    to do a considerable analysis and before any actions is taken by
    him. Only later will he act in concert with a group of pilots who
    have gone through this analysis and have the same goal in their
    life.

    This must be the man who is going to gain the necessary
    analytic skills during four years of an engineering college. By
    having him ATTEMPT to answer the questions below, he will be able
    to start the "thought process" that might encourage him to join
    our preventive effort.

    The pilot, after four years of college will be able to answer
    these engineering questions correctly. Issues such a e = 2.718,
    as the "base of natural logs", will become easy for him. Drawing
    correct conclusions about the behavior of the eye are necessarily
    part of his analysis.



    THE ENGINEERING EXPONETIONAL REPRESENTATION AND EQUATION

    There are two forms of the ( e ^ -t/Tau ) function:

    In Problem One, the minus lens is applied (as a step-input to
    the system) but the lens is removed for each measurement. It is
    necessary that I account for this fact in this analysis.

    In Problem Two, I apply the "perturbation" to the system.
    (For conceptual purposes this contact-lens can not be detected.)
    Since you are measuring the eye with the "perturbation" always in
    it, the equation takes the form as described and as represented.


    SOLVED PROBLEMS

    I would expect that my book, "How to Avoid Nearsightedness",
    will be read by the engineer-pilot BEFORE this test is taken. If
    the man has difficulties solving these problems, then he should
    refer back to this analytic reference book. I have not done
    things perfectly, but this interactive process should help clear
    the air.


    CONSTANTS FOR THE NATRUAL OR NATIVE EYE

    The eye must be considered to be a sophisticated auto-focused
    camera -- for BOTH the accommodation system AND long-term
    focal-status control.

    The accommodation system is presented by me (very simplified)
    on my site as, "A Cybernetic Model of Accommodation." This means
    that the accommodation reproduces the instantaneous visual
    environment as you look at it. That must be understood to be the
    "input", or average-value of accommodation in the equations
    presented below.

    The value of the two "constants", OFFSET = 1.5 diopters and
    TIME-CONSTANT = 100 days, is taken from the fundamental primate
    eye where BOTH the visual environment is controlled and the
    refractive status of ALL EYES are measured.

    All the problems below MUST use these two constants.


    Jon > You first have to get this in a form that is crystal clear.
    There are problems with many since they do not understand
    the concept of "e" the natural base to the number system.


    It is intended that these students will have a tutorial on
    these types of problems. Crystal clarity MIGHT develop later. I
    will do my best.


    Jon > Where is an example problem by which they can follow? You
    have to engage the audience. They do not see where you are
    going with this. There has to be a link and a concoction to
    your thesis, and theirs.


    Otis> That is the purpose of a tutorial. But I have not
    provided that type of symposium. It might be true that
    the pilot has no interest -- in which we are wasting HIS
    time. I have now included a solved-problem as part of
    this presentation.


    THE AVERAGE VALUE OF ACCOMMODATION


    Jon > Is the value for accommodation -1.0 D? Then state this.
    You have introduced other information such as 16 hours a day
    7 days a week which muddies the problem. The order in which
    you state information is critical to a person's
    understanding the problem and providing the solution.


    The INSTANTENOUS value of accommodation is determined by the
    accommodation model presented in "A Cybernetic Model of
    Accommodation". This value must be estimated at this time.

    What CAN be done is to apply a minus one diopter lens. In
    which case you will know that the AVERAGE VALUE has been changed
    by -1.0 diopter (The test group relative to the control group --
    of course).



    CLARIFICATION OF TIME-CONSTANT AND OFFSET


    In Problem 1, the initial focus was provided. The average
    value of accommodation (-.8 diopters) was assumed for both groups.
    The operative factor was that the average value of accommodation
    is changed by -1.0 diopter. The average refractive status of BOTH
    groups was measured at +0.7 diopters.

    After t-zero the control group has an average value of -0.8
    diopters during this test, whereas the test group has a value of
    -1.8 diopters -- after the application of the -1 D lens. This
    issue is to demonstrate that the refractive of the natural eye
    controls its status (or does not change) due to this "delta" in
    the average-value of accommodation. The purpose is to establish a
    QUANTATIVE-PREDICTIVE model for the behavior of the completely
    natural eye.


    The equation then looks as follows for zero days:

    Long-
    Term = Offset + Accommodation + Delta * [ 1 - Exp( -Time/Tau ) ]
    Focus

    Focus = +1.5 D + (- 0.8 D) + ( -1.0 D) * [ 1 - Exp ( - 0 / 100 ) ]

    Focus = +0.7 diopters (before the test starts -- just
    to verify the basic concept for the initial
    conditions.)


    After one day:

    Focus = 1.5 + (-.8 ) + (-1.0) * [ 1 - 0.99]

    Focus = 1.5 + (-.8 ) + (-1) * [ 0.01]

    Focus = 1.5 + (-.8 ) -0.01

    Focus = + 0.70 - 0.01

    Focus = +0.69 Diopters after one day of wearing a -1.0 diopter lens.


    Otis> I hope the above clarifies your questions. I must add your
    commentary to precede and review of these questions.

    Jon > I have your book and I know where you are going to a certain
    extent, but there are times that you are not clear.

    Otis> Understood. That is why I suggest a tutorial on these
    subjects. Many issues in fundamental physics are not clear
    until after you have taken the course.

    Jon > You have these problems so what is the instructional
    objective to the student and what do you want them to know?

    Otis> That by analysis they have a predictive mathematical model
    for the behavior of all natural eyes.

    Jon > Do you know their mathematical background?

    Otis> On entry, I would expect good knowledge of basic math, and
    the ability to solve an equation of this type. After four
    years, I would expect the engineers to understand WHY this
    equations represents the behavior of the natural eye as a
    sophisticated system. This work does indeed does take time
    which I the reason I feel that this study should be
    restricted to only pilot-engineers who understand scientific
    analysis and objective facts.

    Jon > If they do not have the background then you have to fill in
    the blanks to give momentum to the concept.

    Otis> My intention is to present these the problems below as a
    method of getting their minds focused on what they are going
    to be doing one year AFTER they evaluate themselves and
    their own personal goals in life. Thinking is always easier
    that acting. Success favors a prepared mind.

    Jon > If the above are not clear then the following will not work
    either.

    Otis> Correct! It is going to take a highly educated pilot or
    engineer to even begin to understand the issues raised by
    these questions.

    Otis> I MUST rely on the intellectual ability of these people.
    With out that skill, it would be virtually impossible to
    conduct a preventive study.

    Otis> The "standard answer" by the ODs must be item "d", -- if
    they are true to their hereditary, or box-camera theory
    that "environment" has no effect on the refractive
    status of the eye. To be clear on this issue, here
    is the stated opinion stated by an optometrist. He insists
    that all ODs believe as he believes.

    DrL > I do insist that a minus lens has no effect on the
    refractive status of an individual when properly
    prescribed and properly used. Scientists who run this type
    of experiment would not disagree.

    Otis> This is not true. There are many scientists, and
    a great deal of experimental data that contradicts
    DrL's opinion. The "second-opinion" it too strong
    to allow that type of statement to stand without
    challenge.

    Otis> DrL, insists that a minus lens has NO EFFECT on the
    refractive status of the natural eye -- and the purpose
    of these questions is to have you think about the
    accuracy of his answer.

    Otis> Why don't you take the following test, and resolve the
    issue by your own examination of scientific-objective facts.


    I have taken these types of tests in physics -- as you have.

    Initially we object to these questions. But the better idea
    is to read them, put in the numbers, and crank out the correct
    answers.

    After that is done, we can back-track and discuss the reasons
    for the questions, and the implications.

    This is part of the "fundamental" approach, or
    pure-scientific approach as far as I am concerned.

    In all cases "focal status" means the following:

    Check the Snellen eye chart at 6 meters. Read 0.9 cm
    characters.

    If the person can read the character, then use plus in 1/8
    diopter increments, until the .9 cm characters are "just blurred",
    i.e., read only 3 out of 5 characters. This value is recorded as
    the refractive status of the normal eye.

    Similarly, if 1.8 characters are read, then increments of
    -1/4 diopter will be used until the .9 cm characters are read (4
    out of 5 characters. The value of the negative lens is recorded
    as the negative refractive status of the normal eye.

    In all cases, the pilot shall operate the trial-lens case to
    make these measurements. Monitoring shall be provided but the
    accuracy will be certified by the pilots making these
    measurements.

    __________________________________________________


    THE FOUR PROBLEMS


    A test, or "questions" can often serve to clear-the-air, and
    achieve a "clear mind" on a specific issue. The following
    questions are designed to clarify the issues we have been
    discussing.

    I would expect that engineers and scientists could take the
    following test and provide the correct questions.

    I wonder if you could answer the following multiple-choice
    questions and, after you have answer the questions, provide the
    "pros" and "cons" about asking an engineer (or OD) to take and
    pass this test.

    In the following problems use a time constant of 100 days for
    all primate eyes.

    The eye is sophisticated in design and operation. To certify
    your knowledge of the eye's focal dynamic "control" action, please
    review and answer the following questions.


    PROBLEM 1

    One hundred children ( 14 years of age ) have been maintained
    in a distant visual environment of -0.8 diopters for one year.

    We find their initial refractive status (for the entire
    group) is +0.7 diopters

    At this point, half the children begin wearing a -1.0 diopter
    lens. The other half wear no lens. Both groups continue to live
    in the same visual environment, but obviously "environment" is
    -1.0 diopters "closer". Thus, the accoommodation system will be
    "adjusted" for this change.

    Use the following equation to answer the following questions.

    Long-
    Term = Offset + Accommodation + Delta * [ 1 - Exp( -Time/Tau ) ]
    Focus


    The "Delta" in this case equals the applied lens; which is
    -1.0 diopters. The accommodation systemm will be -1 diopter
    "closer" for 16 hours a day, 7 days a week.

    1. What is the status of the test group after 1 day?

    (a) .69 Diopters
    (b) -1.50 Diopters
    (c) .70 Diopters
    (d) Since heredity controls the focal setting of the eye, both
    groups will continue to have the same focal status. In all
    cases, the refractive status of the control group will be
    identical to the test group.

    2. What is the focal status of the test group after 30 days?

    (a) -0.781 Diopters
    (b) 0.441 Diopters
    (c) 1.700 Diopters
    (d) 0.700 Diopters

    3. What is the focal status of the test group after 200 days?

    (a) -.200 Diopters
    (b) .172 Diopters
    (c) -.165 Diopters
    (d) .700 Diopters

    4. What is the focal status of the test group after 360 days?

    (a) +3.250 Diopters
    (b) -3.000 Diopters
    (c) -0.273 Diopters
    (d) 0.700 Diopters


    PROBLEM 2

    The human eye is in the process of growing. As it grows the
    optical components of the eye continually change in value. Let us
    assume that there is a sudden optical shift of +1.0 diopters.
    (This would constitute noise in the system.) This change in total
    power of the eye produces a new refractive status of =0.2
    Diopters. For purposes of this these, the average value of
    accommodation remains constant at -0.7 Diopters for both eyes.

    The original focal status was +.8 diopters. Immediately
    after the one-diopter focal perturbation the focal status is -.2
    diopters.

    This situation could be induced by the application of a +1.0
    diopter contact lens. Please use the equation:

    Focus = Offset + Accommodation - Perturbation * Exp(-t/Tau)

    Focus = 1.5 D - 0.7 D - ( +1.0 D ) * Exp ( -Time / 100 )

    1. What is the focal status of this eye after 1 day?

    (a) -.190 Diopters
    (b) 4.20 Diopters
    (c) -.200 Diopters
    (d) Since genetic information controls the optical components,
    the eye will not recover from focal perturbations. The
    focal status will remain at -.200 diopters. In all cases,
    the refractive status of the control group will be
    identical to the test group.

    2. What is the focal status of this eye 30 days after the
    optical change has occurred?

    (a) .270 Diopters
    (b) -.0592 Diopters
    (c) 1.400 Diopters
    (d) -.200 Diopters

    3. What is the focal status after 100 days?

    (a) +.200 Diopters
    (b) +.397 Diopters
    (c) +0.432 Diopters
    (d) -0.200 Diopters

    4. What is the focal status after 360 days?

    (a) +.617 Diopters
    (b) +.200 Diopters
    (c) +0.772 Diopters
    (d) -0.200 Diopters


    PROBLEM 3

    Eighteen monkeys are living in a caged environment. they
    have an average visual environment of -1.8 diopters. at the start
    of the test half of the monkeys are placed in a hooded (-2.6
    diopter) visual environment. As a result, the environment "delta"
    is -0.8 diopters. The refractive status of both groups (average)
    at the start of the test is -0.300 diopters.

    Using the following equation, calculate the refractive status
    of the test group for the following days after the start of the
    test.

    Focus = Offset + Accommodation + Delta * [ 1 - Exp(-t/Tau) ]

    1. What is the focal status of the test monkeys after 1 day?

    (a) -.308 Diopters
    (b) +1.300 Diopters
    (c) -0.300 Diopters
    (d) Since the eye's focal status is genetically determined,
    the focal status of the test group will be identical to the
    focal status of the control group.

    2. What is the focal status of the test monkeys after 30 days?

    (a) -.445 Diopters
    (b) -.507 Diopters
    (c) +.200 Diopters
    (d) -.300 Diopters

    3. What is their focal status after 60 days.

    (a) -1.433 Diopters
    (b) -6.661 Diopters
    (c) -0.661 Diopters
    (d) -0.300 Diopters

    4. What is their focal status after 360 days.

    (a) +1.078 Diopters
    (b) -0.782 Diopters
    (c) -1.080 Diopters
    (d) -0.300 Diopters


    PROBLEM 4

    CHANGE IN REFRACTIVE STATE BETWEEN THE LEFT AND RIGHT EYES

    The natural eye of primates have refractive states that are
    very close to each other in terms of diopter. It is believed that
    this level of accuracy is maintained because each eye controls its
    refractive status to its visual environment.

    Since the environment of each eye is almost identical, it
    should be possible to prove this is the case. The method is very
    simple. Simply change the "environment" with an applied contact
    lens of a reasonable negative value of -2.0 diopters.

    In this test the refractive status of both eyes is +0.8
    diopters. The average visual environment has been maintained at
    -0.7 diopters.

    A contact lens of -2.0 diopters applied to the left eye will
    change the refractive status of that eye to +2.8 diopters.

    The right eye, with no "perturbation-lens" act as the
    "control" eye.


    The Challenge

    Calculate the refractive status (with the contact lens in
    place) for the following days after the "t = 0" perturbation is
    applied.

    The equation is:

    Focus = Offset + Accommodation - Perturbation * Exp(-t/Tau)

    Focus = +1.5 D - 0.7 D - ( -2.0 D ) * Exp ( -Time / 100 )

    1. What is the focal status of the left eye after 1 day?

    (a) +2.78 Diopters
    (b) +2.80 Diopters
    (c) +0.80 Diopters
    (d) Since genetic information controls the optical
    components of the eye -- the differential refractive
    status of the eyes will remain at +2.0 diopters.

    2. What is the focal status of the left eye 30 days
    after the optical change has occurred?

    (a) -3.50 Diopters
    (b) +2.28 Diopters
    (c) +1.40 Diopters
    (d) +2.80 Diopters

    3. What is the focal status of the left eye after 100 days?

    (a) +0.80 Diopters
    (b) -1.50 Diopters
    (c) +1.53 Diopters
    (d) +2.80 Diopters

    4. What is the focal status of the left eye after 360 days?

    (a) +0.80 Diopters
    (b) -3.20 Diopters
    (c) +0.85 Diopters
    (d) +2.80 Diopters


    __________________________________________


    DETAILED TERMINOLOGY AND DEFINITIONS

    The word "time-constant" refers to the dynamic response of a
    control system. The time-constant of the primate eye (when
    tested) is approximately 100 days.

    The Heredity-offset, or "offset" is a design value. The
    value, from the best experimental data is approximately 1.5
    diopters. Better designed experiments could determine a more
    precise value. I would agree that this value is a function of the
    individual's heredity, and would explain why some individuals
    develop a negative refractive state sooner than others.

    For the problems below use 1.5 diopters for the offset, and
    100 days for the time-constant, "Tau".

    The concept of "perturbation", is that the natural eye must
    have a self-correcting mechanism -- if is a sophisticated control
    system. This "perturbation" could be a change in corneal
    curvature, change in atmospheric pressure, and other random event.
    In order to artificially simulate this perturbation, when can
    place a +1.0 diopter contact lens on the natural eye.

    For instance, if the eye has a measured refractive status of
    +0.8 diopters, and we place a +1.0 diopter contact lens on the
    eye, the measured refractive status will be -0.20 Diopters. If we
    could not "see" this contact lens in the eye, we would measure the
    refractive status to be -0.20 diopters. This is to "trick" the
    eye into changing its refractive status -- as a control system.
    It constitutes critical proof that this process must exist for all
    natural eyes.


    A CONTROL SYSTEM ANALYSIS

    The short-term (accommodation) control of the eye is accurate
    and effective. It is likely that this (averaged) signal is made
    available to the long-term growth control of the eye for correct
    positioning of the retina relative to the accommodation system.
    This is the thesis of this presentation. A feedback control
    circuit will insure that the retina is adjusted to the average
    visual environment of the eye.

    The Laplace transform of the eye's growth control system is:

    1 / (TAU s + 1)

    TAU = Eye's Time-Constant, Approximately 100 days

    Applying a step input to this transfer function results in:


    OUTPUT = INPUT * TRANSFER FUNCTION


    V(s) = [ V(s) / s ] * [ 1 / (Tau s + 1) ]

    Translating this function into the time domain gives:

    V ( out ) = V ( in ) * [ 1 - EXP ( - t / Tau ) ]

    Establishing initial conditions, we find that the equation
    for the normal eye's behavior has a physiological offset of about
    1.5 diopters.

    Focus = Offset + Accommodation + Step Input * [ 1 - EXP ( - t / Tau ) ]

    Where:

    Focus = The focal state of the normal eye.

    Offset = The difference between the average value of accommodation
    and the focal state of the normal eye -- considered over a
    period of months. (For a population of normal eyes the value
    is +1.5 diopters.)

    Accommo-
    dation = Normal accommodation. By design, the accommodation
    system's focal state is almost an exact replica of the visual
    environment. The system is blur-driven and has a time-
    constant of about 1/4 of a second.

    Step-
    Input = The step-input represents a sharp quantitative change in
    the average value of accommodation.

    Exp = Exponential function.

    - t / Tau
    e = Exp ( - t / Tau )

    e = 2.718

    t = Time, in days after the step change is induced in the
    average visual environment.

    Tau = The time-constant of a normal eye. All normal eyes have
    a time-constant. (The typical value for the normal eye
    is 100 days)
     
    Otis Brown, Jul 3, 2004
    #5
  6. Otis Brown

    Dr. Leukoma Guest

    For once, quite making a disturbance and answer your own questions.
    Can you not act like a professional before you exact the same behavior of
    others?

    DrG

    (Otis Brown) wrote in
     
    Dr. Leukoma, Jul 3, 2004
    #6
  7. Otis Brown

    Jan Guest

    Responding on your subjectline Otis.

    You!

    You are the layman when it comes to have the knowledge and experience when
    to prescribe a correcting device in emmetropic, hypermetropic or myopic
    eyes.
    A simple answer on a simple question.


    Jan (normally Dutch spoken)
     
    Jan, Jul 4, 2004
    #7
  8. (Otis Brown) wrote in
    I won't bother solving your first order decaying exponential because to do
    so would suggest acceptance of this model. I don't accept it.

    If you want to do something valuable, instead of just asking people to
    solve your simplistic equation, you could try posting published, peer-
    reveiwed data, that suggests your equation holds for post-developing
    humans.

    Scott
     
    Scott Seidman, Jul 6, 2004
    #8
  9. Otis Brown

    Otis Brown Guest

    Dear Jan,

    If you use an obsolete theory (Donders-Helmholtz) and
    ASSUME that the eye is a box camera --- then yes,
    you then develop words like "emmetropia" (refractive
    status exactly zero) "ametropia", (refractive status that
    is not exactly zero), refractive error (all refractive states,
    since no one has a refractive status of EXACTLY zero.

    Yes, using a warped theory, you can NOT UNDERSTND
    the natural eye as a sophisticated system.

    But, since you can "sharpen" and impress the public
    that walks in your office -- you "win" the argument.

    Yes, you are the "expert" and I am the "layman" as
    long as you use these distorted words to describe
    the behavior of a sophisticated physiological control system.

    But when you use basic words to describe this system
    refractive status (no error or defect), then the
    concept of the eye changes profoundly.

    Testing the primate eye (monkey -- not human) under
    absolute scientific control will ALWAYS show
    the effect that the minus lens has on the refractive
    status of this system.

    Since you totally deny this objective, experimental
    truth, and say "trust me", I must then decide whether
    I am going to trust these objective facts concerning
    the behavior of the eye as a sophisticiated system,
    or trust DrL when he states that a minus lens
    has no effect on the refractive status of the
    fundamental eye.

    I doubt that you have much knowledge of the natural
    eye as a sophisticated system, since when I pose
    explicit questions do you -- you refuse to answer
    them.

    I conlcude that you are a layman about engineering-scientific
    issues concening ONLY the behavior of the natural eye
    that can have positive or negative refractive STATUS
    depending of the average-visual environment.

    As always, I enjoy these pleasant conversations,
    provide we use correct-words to describe the behavior
    of the natural eye. Use distorted words to describe
    this natural process, and you will form a distorted
    idea of the behavior of this optical control-system.

    There are fortunately some ODs who are willing to
    use the plus on their own children, and will help
    other parents -- provided the parents will accept
    this "new concept", and will help the child maintain
    clear distant vision through high school and college.

    That is the true nature of the "second opnion" and
    how it could be applied in the future.


    Best,

    Otis
    Engineer
     
    Otis Brown, Jul 6, 2004
    #9
  10. (Otis Brown) wrote in @posting.google.com:
    FWIW, I think that in general, parents who are the investigators should
    never do research on their own children. The risk is that parents can
    apply undue influence to seek assent from the child.

    Scott
     
    Scott Seidman, Jul 6, 2004
    #10
  11. Otis Brown

    Dr. Leukoma Guest


    Otis did misquote me, as he has often done in order to further his
    preposterous notions. He cannot win the argument on its merits.

    DrG
     
    Dr. Leukoma, Jul 6, 2004
    #11
  12. Otis Brown

    Dan Abel Guest


    Where did I post myself as an academic? I'm not. For all you know, I
    could be a janitor or groundsworker. About half of the employees at SSU
    are academic, the other are staff. And even if I was an academic, what if
    I was teaching in the Art History department? What qualifications would I
    have to talk about the behavior of the eye, or a mathematical model of the
    eye?


    I made no reference to "quack". I did see some ducks this morning, but
    they were very quiet.


    Because this entire group is out of my area of expertise. If someone
    wants to ask about personal experience with severe myopia, cataract and
    retinal detachment, then I've been through those.


    Why would I want to make an assertion with no scientific proof? That
    doesn't sound very smart to me.


    Refusing to answer questions in areas I'm not qualified in doesn't make me
    a wimp. Demanding that I answer questions when you have no clue as to my
    knowledge and background makes you unreasonable.
     
    Dan Abel, Jul 6, 2004
    #12
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