RM asks the wrong questions -- and always ingores the correct answers.

Not.txt

Subject: Re: Challenging questions that Otis can't answer

Dear Optomterist RM,

My, that's presumptuous!

Since you have already stated that I "can't answer" you are
obviously profondly biased by that specific satement.

I assume that:

1. You will not let me answer, or

2. You will totally IGNORE any answer I provide about
the behavior of the natural eye as a control-system.

However, thanks for your thougtful questions.

I will forward them to the scientist Dr. Colgate as well as
other engineers interested in true-prevention.

Remember that Donders-Helmholtz is a THEORY where you ASSUME
that it is FROZEN (as in box-camera).

It is this assumption that has failed. Any good engineer can
optically analyize a box-camera. The calculations can be carried
out to three, four and five significant figures. But when you are
all done -- you have proven nothing.

The answers you get depends on the type of questions YOU
LEARN TO ASK.

And the issues (and questions) I ask have to do with the
fundamental question of the dynamic behavior of the natural eye
(as an entity).

But, I will review your summarized statement that assumes the
Donders-Helmholtz theory concerning the eye.


Best,

Otis

Engineer

____________



RM > Questions for Otis:


RM > 1. What physical structures within the eye are changed by
using plus lens therapy on an anatomical myope (e.g. myopia
caused by increased axial length of the eye or increased
curvature of the cornea)?

Otis> The concept of "length" is an extrapolation of the
measurement of a refractive-state. To calculate a "length"
you must assume a frozen box-camera.

RM > To state it another way, exactly what is it that plus lenses
do that causes the visual image to be brought to focus on
the retina of a myope?

Otis> Assuming a refractive-state of -1/2 diopter, then the
accommodation system will maintain sharp focus up to -1/2
diopter. The natural eye can be made to change its
refractive status from a postive value to -1/2 diopter by

Otis> a. A strong minus lens. Thus this reafractive state in not
open to box-camera analysis. It CAN BE a temporary state,
and provided that the visual environment is all moved out to
"infininty", the same process that created the negative
refractive state, can be relied on to produce gradual
clearing -- it the person has the persistance to use the
plus correctly.

Otis> b. Again, your mistake is to ASSUME a box-camera analysis
-- which is a conceptual error in the first place.

RM > What anatomic structures within the eye are changed to
achieve this?

Otis> a. I only report what is actually measured (on an
input-output) basis. You are asking for spculation.

RM > Do you propose that the length of the eye shortens?

Otis> a. No. It is obvious that when you place a minus lens on
the natural eye, and the refractive status of this natural
eye changes in a negative direction that one, several or
several refractive items MUST CHANGED. The important fact
is the truth of direct change (as a sophisticated control
system) and not be concerned about which -- of several --
components were necessarily chaned to achieve the above
stated factual result.

RM > Do you propose that the curvature of the cornea flattens? Do
you propose that the index of refraction of ocular tissues
is decreased?

Otis> a. I am only concerned that when you apply a step-function
INPUT to this sophisticated system, that the natural eye
changes its refractive state following the e ^ (-t/TAU)
function. I you stating that this does not happen, and this
result is not repeatable?

RM > 2. How can you be so opposed to minus lenses for myopia
treatment yet be unopposed to the use of LASIK surgery?

Otis> a. That is not what I said. A person has the right of
informed choice. I am never going to stand in a person way
-- what ever his choice. Once you start wearing the minus
lens, the concept of true-prevention is moot. If a person
is at -6 diopters, the Lasik, or whatever is a matter of
that persons choice. I am not "opposed" to the use of a
minus lens either -- if that be the person's choice.

RM > In LASIK surgery you are simply removing plus power from the
cornea by flattening it's curvature (equivalent to adding
minus lens power) so as to get the visual image to focus on
the retina?

Otis> a. Assuming a box-camera "picture" then the analysis is
correct.

RM > 3. Explain how it is that plus lens therapy works for only
younger patients but not for older ones?

Otis> a. I NEVER use the word "therapy". And as far at "works" I
say that the person himself must see the results. This
requires a strong will in the person, since true-prevention
is never easy. Further the person is not a "patient". I
expect that he must have the insight of an engineer to work
this issue correctly. Therefore the person would have to be
old enough to understand the issues, and the effort it will
take to achieve the desired result. No, you can never
"prescribe" the plus for prevention.

RM> Do you think that the decreased effectiveness of plus lens
treatment for myopes correlates with the onset of
presbyopia?

Otis> a. As most of these ODs on sci.med.vision have stated, the
plus or minus lens has NO EFFECT on the refractive state of
the eye. I agree that prevention with the plus MUST START
BEFORE a minus lens is used. The issue is whether the
person himself is effective in clearing his vision to pass
the DMV requirement -- and thus avoid any use of the minus
lens.

b. Do not confuse "old age" vision situations with
true-prevention for a young pilot. An individual at 20/50,
who wishes to clear to the required standard (and a
refractiv state of zero) is not concerned about his
refractive status at age 65.

RM > Doesn't this observation support the notion that plus lens
therapy is simply just helping the subpopulation of myopes
that have an accommodative component to their refractive
error?

Otis> a. I do not use the term "therapy". Further I do not use
the term "refractive error".

RM> What about anatomical myopes?

Otis> a. If you place a strong minus 6 D lens on a population of
young eyes, and they go "down" to -4 diopters -- then YOU
tell me -- are they "anatomical myopes" or regular "myopes"
or accommodation myopies or what, or are they "minus lens"
myopes?

RM > How do you propose we treat anatomical myopes who apparently,
by your own experience, aren't candidates for plus therapy?

Otis> a. I do not propose you do anything. In fact, the
preventive effort is proposed for an engineer-pilot himself
-- should he be interested in "protecting" his distant
vision through four years of college. Obviously this is his
choice -- and certainly not your choice or decision at this
point.

RM > 4. Explain exactly what the "devastating effects" of minus
lens treatment are for myopes-- and I don't mean
OVERMINUSING them.

Otis> a. The point of intelligent "Shawn's" work in clearin his
vision to 20/20 is to AVOID the use of a -1.5 diopter lens
-- thus avoiding the devasting effects of stair-case myopia.
The effects result in the percentage of detached retinas
that develop in higher levels of myopia. (Perkins study --
"Morbity from Myopia) An ounce of prevention is worth a ton
of "cure".

Otis> b. Again you totally miss my point. You determine if the
natrual eyes refractive state "follows" the applied minus
lens to PROVE a dynamic system -- on an "input" versus
"output" basis. Once an engineer reviews this OBJECTIVE,
REPEATABLE, SCIENTIFIC data, then the intelligenct, highly
motivated pilot can make the decision to agressively use the
plus to clear his distant vision. That is by his judgment
-- not by YOUR judgment.

RM > I mean simply giving them just enough minus lens power to
focus the visual image on the retina?

Otis> a. If the pilot is passing the required Snellen-DMV test,
then there is no requirement for wearing a minus lens, i.e.,
20/40 vision. It is true there will be SLIGHT blur -- but
not enough to fail that DMV test. The goal for the pilot
then is to clear his distant vision, by optically moving all
"near" objects to "infinfinity" with a strong plus for all
close work. If the pilot is persistant, then the prediction
is that he can clear his distant vision in from six to nine
months.

RM > Explain what the devastating effects are at an
anatomical/physiological/biochemical level.

Otis> a. I think that the Perkins study is clear enough.
Nearsighedness is something you should wish to avoid for
that reason.

Otis> b. Using you assumed box-camera model I suppose. The
purpose of true prevention is to AVOID getting into
nearsightedness and thus AVOID these effects. You seem to
miss that point.

RM > What structures within the eye are changed by the minus lens?

Otis> It is sufficient to know that the natural eye moves from a
positive refractive state to a negative refractive state --
as a control system. Analysis of how the natural eye
achieves this result can be determined by future research
and analysis. The point is that the natural eye is proven
to do this.


RM > Answer these questions Otis. Don't give us any more one-rat
studies or case reports.

Otis> a. Would you accept a two-rat study?

Otis> b. You are not going to dictate conditions my friend. If
you don't like the experimental data that demonstates that
the natural eye's refractive status follow's its applied
visual environment - just say so. If you want to
"quick-fix" the public with a minus lens, and ignore the
stair-case myopia that develops, then you can continue to
say it is there "genetics".

RM > Don't sight any old texts or drop the names of famous old
optometrists.

Otis> a. I am not certain which "old texts" I should ignore -- on
your order. Which ones? Introduction to Physiological
Optics? Control Theory? Scientific publications by Dr.
Francis Young? Which names should I "not drop". You tell
me. What, you don't like famous "old" optometrists who are
now working for a person's right to a second-opinion? That
is hardly even professonal on your part. Are you going to
give me a list of the "right" optometrists? I wonder.

Otis> b. And I assume that you are going to require that I ignore
all scientific studies where you don't like the results. I
have been down that road with other biased optometrists.


Otis> c. You have the bad habit of wishing to dictate conditions.
Sorry, I don't agree with you. I pay attention to
scientific facts concerning the dynamic nature of the
primate eye -- and you do not. Why should I listen to you?

RM > Just try to explain it on a truly scientific level.

Otis> a. It depends on what you mean by "a truly scientific
level". You probably mean explain on a "box-camera" level.
You can use a ray-trace computer to do that.

Otis> b. Given DrJudy's statement that she was going to ignore
all experimental data taken from animals -- I assume you are
going to do EXACETLY THE SAME THING.

Otis> c. You exclude any an all scientific data you don't like,
or don't like the implication of the experimental data.
That may be "optometry" but is certainly is not science. It
is simple bias with tunnel vision my friend.

Best,

Otis Engineer

RM

 

No Otis, we have been waiting for you to provide a cogent understandable
explanation for the effects that you claim your plus lens treatment has.
You provide none. You just keep repeating that it DOES work and that we are
fools and conspirators for not seeing it your way. I want to understand
the nuts and bolts of how it works given the known anatomy and physiology of
the eye. The eye is not an equation Otis. Perhaps I will coin that term as
you like to coin the "box camera" phrase. The eye is constituted of
collagen, muscle fibers, nerve cells, blood vessels, fluid-filled chambers
in a dynamic state, etc. How is it that plus lenses interact with these
structures to reduce myopia? What is it about the age of the eye that makes
it work better in younger people? I have a theory-- plus lenses allow
relaxation of the ciliary muscle in those individual who have accommodative
myopia and in no others.

THE EYE IS MUCH MORE THAN AN EQUATION OTIS. Structure reflects function
Otis. If the functioning of the eye changes after plus lens treatment then
you need to tell us how and where the change(s) occurs. Again I state--
OTIS DOESN'T ANSWER THIS BECAUSE HE CAN'T. HE DOESN'T UNDERSTAND THE
FUNCTIONING OF THE EYE. The eye is not an equation Otis.

I'm glad you read Donders and Helmholtz. And forget the box camera analogy.
You seem to perceive the eye as either an equation or some kind of simple
mechanical device that you can easily comprehend.

Wrong Otis. Axial length of the eye is measured objectively by ultrasound
in an A-scan. I can tell you for certain that you can repeatedly measure
the axial length of the adult eye over a time span of years and it does not
change. Length is not an extrapolation of refractive measurements Otis.

Your theories, however, are an extrapolation of the few cases of
accommodative myopia where you can demonstrate ciliary muscle relaxation
using plus lenses.

Exactly Otis. This will work for young people whose myopia is due to
increased ciliary muscle tone. These individuals are called accommodative
myopes and constitute the minority of the myopic patients. Your theory
applies only to younger individuals with over-functioning ciliary muscles.

I see many many children and adolescents who have been myopic for a long
period of time and have never received a minus lens. Why do they some
continue to progress toward myopia Otis? As pointed out by MT, they have a
net plus power to the optics of their eye as if they are wearing full time
plus lenses yet their refractive status does not improve and oftentimes
worsens. Why is that Otis?

Again, you have an equation-based understanding of the eye. It is like a
black box to you and you don't understand what's inside it and how it works.
Structure reflects function. Any changes within the eye caused by your plus
lenses MUST be reflected in a change in the anatomy/physiology of the eye.
Don't you wish you knew it? You will never gain credibility in the medical
community until you demonstrate it.

You don't understand how the eye works. You can't explain it.
I think I know what explains your observations-- your plus lens treatment
works for accommodative myopes only.

I will have to ask you to explain what you are saying in another way. Are
you saying that if you give the eye minus lens power that its refractive
state will change to become more myopic? If so, that CAN happen but only in
some younger patients (with functioning ciliary muscles) if you give them
more minus power than is needed to focus the image on the retina. These
patient may develop an accommodative myopia as we have discussed at great
length already (Geez!!). But this does not apply to all young people and
certainly does not apply to post-presbyopic patients. These patients will
reject the excessive minus power and will see more clearly when their
anatomical myopia is corrected precisely. Your equation is an
oversimplification and does not apply to most patients. They eye is not an
equation Otis. All myopes are not accommodative myopes Otis.

OK, let's assume some other kind of picture of the eye. How then according
to your equation theory of the eye, or your black-box theory of the eye,
does LASIK work. The fact is that refractive techniques all are based upon
an understanding of the components of the eye and how they function
together. Structure reflects function. LASIK, cataract surgery, etc. would
never have been developed if we all had a black-box or equation based theory
of the eye.

When I ask about age it has nothing to do with the persons ability to
understand or follow directions. It has to do with how the eye functions
and the fact that it's ability to change refractive state is quite high in
younger individuals because of the functioning (and OVERfunctioning) of the
ciliary muscle. Your plus lens technique can only work on myopes with
overfunctioning ciliary muscles (i.e. accommodative myopes).

So if you are 65 you don't care about your refractive status? Anyway, are
you ready to admit that your plus lens theory is ineffective in presbyopic
patients? If so, can we break out the dreaded minus lenses for those people
(who apparently don't care about their refractive status anyway)?

I could tell you precisely if you paralyze the ciliary muscle with a
cycloplegic agent and then do a refraction on them. An important point is
that not all of them will "go down". As stated above, some will adapt to
the minus lens and will develop a counterbalancing increased ciliary muscle
tone. These are called accommodative myopes. Some will reject the minus
lens and will see blur at distance. Some will show no lasting effect of the
minus lens treatment at all and will be neutral just as before. And
besides-- who is putting such an excessive minus lens on anyone anyway? Why
do you think this kind experiment relates to the way humans are treated by
eye doctors? If eating too much causes obesity do you propose that we ban
food altogether?

OK, now we are getting somewhere. Your plus lens treatment is best suited
for young engineer-pilots.

Retinal detachment is a concern for high axial-length myopes. It has
nothing to do with myopia induced by increased ciliary muscle tone.

You know what I mean. Explain how it works. Explain what part of the eye is
changed. Show the studies that demonstrate it.

Sometimes primate studies are quite useful. But sometimes they are not. I
will listen to animal studies unless they are proven not to apply to humans
in a subsequent study.

No, I just haven't seen any data from you yet. Only declarations and
second-hand case reports. You just keep repeating that your approach DOES
work and that we are fools and conspirators for not seeing it your way.
Your method likely works for the subpopulation of young accommodative myopes
but not for other myopes.

What really irks me Otis is that people like you, who propose this kind of
snake-oil fix for vision problems, can mislead people. I have had patients
who told me that they heard this kind of voodoo crap on the radio from Paul
Harvey or bought some training materials after seeing television
advertisements starring Marriet Hartley. I respect your right to think
whatever you want to think. I hope you go off and do some studies to prove
yourself right and the rest of us wrong. But until then, I'm placing my
bets on the understanding of the visual system that the majority of us have.
It works, it's effective, and it helps people. You are misleading people
and in my opinion have an imperfect understanding of what you are talking
about.

 

I think that the point is that Otis and his ilk need to be able to show
that their proposed treatment works. This has not been done. Then they
can worry about the mechanism. They cannot prove that it works, and so
they hide behind this wall of obfuscation. All they need to do is a
controlled study. Of course, this will never happen, because it needs to
be done by engineers, according to Otis.

DrG

 

WOW-- I was told about this newsgroup by a faculty member from an opto
school. Very interesting! To cut through the BS I will simply snip
out some comments from the last long-winded reply with which I agree.

The issue of myopia prevention has a life of its own. It has gone on
for generations. It seems to be a complicated topic and there are
probably genetic and racial differences that we yet do not understand.

 

Dear RM,

Again, thanks for your commentary -- I always
appreciate the thought.

I consider the minus lens to be "obvious", and
the very few people have any interest in
"prevention" when it must be accomplished.

My interest was is "understanding" the difficulties
of prevention -- when seen from the perspective
of optometry. And is was Jacob Raphaelson who
supplied that persepctive -- in his story
of "The Printer's Son". That convinced me
that true prevention could never be "worked"
by an optometrist -- and the the person
concerned with it would have to make
that kind of decision himself -- however
hard that might be for him.

As far as representing the behavior of the
natural eye -- as dynamic -- then I judge
that has been accomplished on and "engineering-scientific"
level, were resolution is in the facts themselves --
and not in your opinion.

I do think you for absolutly rejecting ALL primate
studies, and ALL animal studies as being to
"disturbing" to evalulate. But no one is
forcing you to "think straight", and
certainly I am not going to do it.

But I will again save this and forward it
to the interested parties.

I do agree that the "high-level" appreciation of
testing the nautral eye as an "input" versus "output"
has never occurred to you -- and this type of
analytic thinking can NEVER be reduced to a "quick-fix"
supplied to the public that walks in off the street.

I could not do it. And I would never "pressure" you
to do it. But for those who can "push-back", and
for a different perspective "paradigm", then I believe
that a preventive alternative is possible -- even
if you can not be part of it.

Thanks,

Otis

_______

 

Oh, so I'm long-winded huh? Well I guess you are right. Sorry

I've got to apologize to everyone. I normally just lurk around this NG and
occasionally throw in my 2 cents. But about a week ago Otis the engineer
went off on his rant and it just pissed me off. I've tried to explain as
much as I can to him over and over again but it's to no avail. Last night I
even looked over some old posts by Otis from about a year ago and all the
same points and issues that I've made have been discussed with him by others
previously. I realize that there is no way to get the guy to ease up. The
problem is that he acts like he is some kind of intellectual expert on
vision and he could easily mislead people who use this newsgroup. His
prevention techniques have no chance of helping 95% of all myopes.

I think I will just put together a "disclaimer" about Otis and post it in
reply to any "help" he tries to tell someone when they innocently ask a
question in this newsgroup. I will try to make it fair and informative. I
could do it for Rishi and Evaristo also but they do a pretty good job of
discrediting themselves. Otis the engineer however uses mathematical
equations and drops the names of real doctors which creates a false aura of
credibility around the BS he spouts.

 

Dear RM,

Since you seem to have a scientific "bent", here
are the result of ADOLECENT-PRIMATE studies to
determine the amount by which the primate eye
changes its refractive status -- as the average
visual environment is changed.

Briefly -- a population of natural primates were
placed in a situation where an accommodation delta
(long-term) of -0.8 diopters whas iduced in the
test group. The control group had no delta.

The refractive status of the test group changed
according to the function e ^ (-t/TAU), while
the refractive status of the control group
remained the same.

Below is the calculation for the correlation coefficient
for the accommodation system -- relative to the
refractive state of these natural eyes.

__________________



FOCAL STATE CORRELATION TO THE SNELLEN EYE CHART

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 focal state of +0.7 diopters.


THE CORRELATION COEFFICIENT DATA AND CALCULATION

(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 normal eye, correlates with the equation:

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


STUDENTS "T" CALCULATION FOR THE CORRELATION COEFFICIENT

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" distribution:

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

Where:

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)
..001

2
t = 0.97 / SQRT [ ( 1 - 0.97 ) / ( 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
focal state of the normal eye.


THE REPEATABILITY OF THIS EXPERIMENT TO OBTAIN
THE SAME CORRELATION COEFFICIENT

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

Where:

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

Values:

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 normal 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
normal eye's behavior. It is very unlikely that future experiments will
support the Helmholtz-passive model of the normal eye's behavior.

___________________________

The conclusion does not analyize the "box camera" picture
of the eye you love to analize -- because:

1. It is not reasonble.
2. It is not accurate in predicting the
behavior of the natural eye.

Please remember these are analytical arguments -- not
to be part of "optometry" at all.

RM -- Please tell me again that there is NO CORRELATION
between the refractive status of THE NATURAL EYE and
it average-visual environment.

Best,

Otis



__________________________


CONCLUSIONS

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 normal 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. (5)

In synthesis, we develop a dynamic design which will account for the
maximum number of facts known about the normal 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 predictions.

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 out.

Accuracy and stability of the normal 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 focal 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 strengthened.

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 expeerimental data that is available to
us.


REFERENCES

1. Young, F., Leary, G. VISUAL CHARACTERISTICS OF APES AND 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)

3. Brown, O., Young, F. PHYSIOLOGICAL MODELING: THE LONG-TERM GROWTH OF
THE EYE, (133-136) The 8th Annual New England Bioengineering Conference
(1980)

4. Young, F. THE EFFECT OF RESTRICTED VISUAL SPACE ON THE PRIMATE EYE,
American Journal of Ophthalmology, Vol. 52, No. 5, Part II, November
1961

5. Brown, O., Young, F. THE RESPONSE OF A SERVO CONTROLLED EYE TO FOCAL
PERTURBATIONS, The 2nd Annual conference of the IEEE Engineering in
Medicine and Biology Society (1980)

6. Hayden, R. DEVELOPMENT AND PREVENTION OF MYOPIA AT THE UNITED STATES
NAVAL ACADEMY, Archives of Ophthalmology Volume 25, #4 (April 1941)



________________

 

occasionally throw in my 2 cents. But about a week ago Otis the engineer
went off on his rant and it just pissed me off. I've tried to explain as
much as I can to him over and over again but it's to no avail. Last night I[/QUOTE]


I was wondering what you were doing. Otis has the One True Faith, which
he calls true-prevention, I guess to differentiate it from
false-prevention? It's no good to argue with him, he's already decided
what he believes.

I think that Bev has already done something like this. She hasn't named
Otis or described his belief, but simply said that if it sounds too good
to be true, it probably isn't. I think that it would be useful for you to
put together a quick "disclaimer". Otis always posts the same beliefs, so
you wouldn't need to edit it each time.

 

There is a distinct possibility that Otis is two bricks shy of a full load.

DrG

 

What an elegant and romantic story about what spawned your interest in
myopia prevention Otis.

But I have come to accept DrG's suggestion that you have some real
psychological issues. Perhap you picture yourself as some kind of martyr in
a "war" against the convention wisdom of modern-day eye doctors.

You will never address my questions directly. You reply obliquely to
difficult questions by just reverting to your mathematical equations and
black-box input/output analysis of the human eye. How does the old saying
go-- "if you can't dazzle them with brilliance then baffle them with
bullshit".

I was a fool to think that a logical discussion with you could change or
dampen your profuse opinionated postings in this newsgroup.

------------

 

Otis, I never said the anything in my posts about the correlations between
the natural eye and it's visual environment.

By the way Otis, I and everyone else who reads this newsgroup is undoubtedly
impressed by your mathematical skills. But the eye is composed of
biological materials and you never seem to be able to discuss or explain
anything in any other way than equations and black-box circuit diagrams.

How does the old saying go-- "if you can't dazzle them with brilliance then
baffle them with bullshit".

Nope Otis, you can gain access to the accommodation system (which controls
primarily the eyes short-term focus). You can observe how it functions in
real-time. You can paralyze it via the use of cycloplegic drugs. You can
observe the changes it makes on the crystalline lens.

Otis seems to favor only indirect approaches.

Yours directly
RM

 

That is incorrect. I am not impressed by sophistry.

DrG

 

Careful, there. Every process in our bodies is, to some extent,
describable by differential equations, chemical reactions, biomechanical
descriptions, etc. Good models (with the stress on good) take these
factors into account at an appropriate level, and can teach us alot about
physiology.

Of course, the model we're talking about now has been invalidated at every
corner, yet we continue to discuss it for some reason.

Scott

 

Scott,
You are certainly correct. I harken back to the days when I was in graduate
school taking electron microscopic pictures of the eye while some of my
fellow grad students were deriving differential equations to describe the
psychophysics of color vision. I personally have a biological bent on
things. I want to see it, know what makes it up, and know how it operates.
Many of my graduate student friends, as well as Otis the engineer, have a
different approach. Both approaches have value.

Nevertheless, the functions that psychophysicists describe mathematically
must definitely have anatomical, physiological, and biochemical correlates.
We can describe anything as if it were a black box or a circuit diagram, but
that doesn't help us understand how it works unless we can open the box and
see what's inside. What good does it do to describe mathematically how
visual acuity is diminished when a cataract develops unless you know what
the cause is, which therefore leads you to understand what the problem is
and how to correct it.

Not to be long-winded again, but I acknowledge your point.

Perhaps more important is that Otis' equation which describes (I think) that
increasing the minus lens power in front of the eye leads to an increased
refractive error in the eye-- i.e. his "stair-step" equation-- does not
apply in most cases. It might be true in a subpopulation of young people
who develop accommodative myopia, but not in most others. Some young people
report blur when you overminus them and reject the lens outright. Some
people can clear their vision with the excessive minus lens but, after
wearing it for awhile, when you retest them you find they have the same
original refractive error. Otis' lack of understanding about what is
actually inside the black box causes him to overlook that the action of the
ciliary muscle is responsible for why some people seem to respond to plus
lens treatment.

 

But alas, there is no proof whatsoever of its validity in any subset of
myopes.

DrG

 

Yes, perhaps there is no scientific proof. It is just another "case report"
or a clinical observation that I have made that causes me to actually agree
with Otis (ugh!) that some accommodative myopes can perhaps benefit from 1)
not wearing their minus correction unless they absolutely need it, and 2)
considering using weak readers when doing prolonged near work.

Of course most of them won't wear the plus lenses at near because it's
impractical. Nor would I. And regardless, I still have never seen any
"devastating effects" from a minus lens. Certainly not retinal detachment
as Otis tried to imply in one of his recent posts.

 

Actually, I meant that there is no independent proof of the predictability
of his mathematical equation.

Lecturing optometrists on accommodative myopia is like preaching to the
choir.

DrG

 

RM > But the eye is composed of

______________

Dear Scott,

Thank you for that observation. To a certain extent,
learning to ask the "right" questions -- leads to
better answers.

The type of questions these ODs ask remined me of
a beginning-tech who does not understand
the design of a rocket control sytem.
He will ask detailed questions about individual
resistors, hydrolic pumps, in great detail -- but
will not understand the over-all concept of
stability and control. You can not dissect a
"dead eye", taking all the parts, lens, cornea,
retina, and examining them under a microscope -- and
then have any concept of how these separate parts
work as a "system". They insist that "I" do it,
and I insist they don't know how to establish the
behavior of a natural physiological control system.
Specifically:

________________


Measurements on individual optical components of the eye are exacting,
and it is difficult to say which optical component causes a specific problem.
The researcher can be aided by an engineering approach to this complex system,
since the eye is an intricate data-processing system. The primary
neurological process is controlling a dynamic (100 day time-constant) focal
system on a microscopic level.

_________________

I do appreciate that they are working very hard to find
a simple solution that will satisfy the general
public that walks into and office. The public will
in fact be very angry with any attempted discussion
of the preventive alternative -- a fact that I acknowlege.

My primary interest is to face this difficult truth,
and follow the suggestions of Dr. Colgate on this
issue. I am more interested in accounting
for the eye's high-level of technical accuracy,
rather tha being particularly concerned with
the limited goal of an OD.

You find out how a system behaves, and then inducing
"perturbations", and seeing how the system
responds to these transient disturbances.
That is what a "systems" approach is all about.
Here is a review of that analysis.

Enjoy my friend. New ideas and discussions of
these concepts make for great analysis
over wine and cheese receptions.

Otis
Engineer


____________________


CONCLUSIONS

If the normal primate eye is to achieve a high level of focal accuracy in
the presence of continuous perturbations, the author has concluded that the
eye must employ dynamic control to set its focus. This chapter presents a
high performance model that provides a focal control mechanism that is, as far
as we can determine, consistent with all the physical evidence pertaining to
the normal eye's behavior.

The model evolved as a result of a long investigation in which many
preliminary approaches were discarded because they led to inconsistencies. It
is clear that the number of approaches that can satisfy the evidence is
limited. An electrical engineer, when faced with similar engineering
requirements for focal precision, will develop this type of design to meet the
accuracy requirements of the eye.

The philosophy of this chapter has been to study the focal control
process of the normal eye by treating it as a design problem. The procedure
followed is to develop a system model with the focal performance capability
comparable to the normal primate eye.

Measurements on individual optical components of the eye are exacting,
and it is difficult to say which optical component causes a specific problem.
The researcher can be aided by an engineering approach to this complex system,
since the eye is an intricate data-processing system. The primary
neurological process is controlling a dynamic (100 day time-constant) focal
system on a microscopic level.

It should be remembered that there are several major optical components
of focus, any of which can dramatically affect the focal state of the normal
human eye. While the eye is growing, these components are continually
changing in value.

When a physiologist experiments on this complicated data processing
operation, he is in the same position as a technician who is presented with a
computer system that determines rocket guidance. He is then told to make
measurements on the individual components of the device until he determines
which component establishes the tracking accuracy of the system. Actually,
the physiologist is in a more difficult position because so much of the data
processing of the eye is at the molecular level, almost beyond the reach of
his instruments.

The mathematical systems concepts used in automatic control evolved out
of necessity, as it became apparent that modern servo systems could not be
understood by studying the characteristics of their individual components.
This truth applies just as strongly to complex processes encountered in
biological-optical systems. The electronics engineer can establish a solid
mathematical foundation for an analysis that will accurately predict the
normal eye's focal control response.

The same equation that precisely anticipates the normal eye's
perturbation control also predicts that nearsightedness can be avoided. In
addition, the equation can give conceptual and practical guidance to a
successful nearsightedness avoidance effort.

There are other more sophisticated means of determining the eye's
tracking accuracy, and these techniques will be developed in the next chapter.


APPENDIX

Focal Accuracy: The eye is about 2.4 cm in length. The eye must have a
focal power of 57 diopters to focus light on the retina. The focal status
histogram for normal eyes has a standard deviation of .843 diopters, and a
probable error of .843 X .674 = .568 diopters. We may, therefore, specify
that the eye has a tracking probable error of .568/57 or approximately one
percent of its total focal power. This is the worst-case value. For a number
of reasons, we should expect that the tracking accuracy of the normal eye will
be considerably better than one percent. In the next chapter we will provide
an analysis that demonstrates that the actual tracking probable-error is on
the order of 1/10 diopters.


REFERENCES

1. Young, F., Leary, G. VISUAL CHARACTERISTICS OF APES AND PERSONS
(207-225) Progress in Ape Research (1977)

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

3. Brown, O., Young, F. PHYSIOLOGICAL MODELING: THE LONG-TERM GROWTH OF
THE EYE Proceedings of the 8th New England Bioengineering Conference
(1980)

 

(Otis Brown) wrote in

Please state the name of the author of this article as well as the journal
and year in which it was published. I see that the bibliography references
only three articles, all published more than two decades ago. That is
ancient history.

DrG

 

Dear DrG,

Subject: Sub-set of eyes with refractive status of
-1/2 to -3/4 diopters (20/50 to 20/70)

This subject would depend on what is considered
"proof" by the engineer-pilot concerned with the
issue.

Provided the effort is run under "scientific" (not
medical) protocols -- then I believe that
major successful (i.e., pass the Snellen-MDV,
pass the 20/20 line) could be achieved
but the pilot himself -- who had the
same motivation that Shawn did.

Under proper circumstances I would gladly
give of my time to organize this effort
at a four year aeronautical collage
among the (new) scientists that are
concerned with it.

Please remember -- even completely successful
results (70 percent clear to 20/20) these
results could not be reduced to dealing
with the general public -- in 15 minutes.

Further, the goal is true-prevention, which
would be the real goal of this effort.

I am ready to do it -- are you?

Best,

Otis
Engineer