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Medical Forum / General / Vision / June 2004The "Catch-22" in conducting a prevetive study
From: Otis Brown To: Scientists, engineers and friends who think logically Subject: Statistical testing on a population of natural eyes to stop the -1/3 diopter per year movement seen in the eyes of military students. Steps: 1. Clearly state the "null hypothesis" that there is no relationship between the visual environment and the refractive status of the natural eye. 2. Each individual in the study must understand college-level statistics, and the concept of significance levels. 3. It is possible that the null hypothesis might be confirmed. That could be the goal of this type of study. It would be wise to confirm this truth as quickly as possible. Analytical statistics can do that for you -- if properly used. 4. The statically analysis I provided will confirm this in about eight months. 5. But to be honest, the pilot using the plus must use it with great force. (i.e., for all close work, and he must read at the "blur point". Beyond that there is not too much to say, other than 99.9 percent of the population will not take intelligent use of the plus at the threshold seriously. Below is some more "OD opposition" to this concept of honestly testing the natural eye (as an auto-focused camera), and confirming the null hypothesis. Catch-22: As an engineer I can test all eyes (except humans). I can verify everything except for the above test. The ODs on sci.med.vision then insist that I perform this test on humans -- knowing full-well that I, as an engineer can not do the above test. So then proclaim, "prove it", and successfully obstruct or prevent the very type of final testing that would prove the null-hypothesis, or prove that the -1/3 diopter per year had been successfully prevented. Beyond a certain level this becomes a "head game", where they hold "all the cards", and I am expected to play into a "stacked deck". The "game" is of course that they are always "right" and everyone else is always "wrong". Yes, I understand the game of power and "position". It is a shame that so many intelligent people fall victim to this "game". Please enjoy the following: ____________________________________ Dear Judy, Re> My opinion??? I think it is a fact that you did not do a study and that you made up results that might be found if a study might be done, and then you did the statistics on the made up data and found it to be significant. Dr Judy Otis> The statistics were not "made up" as "Dr Judy" would have You believe - for obvious reasons. Otis> The statistics come directly from Francis Young's study with young children wearing a plus in the form of a bi-focal. The only difference, it that a intelligent pilot-engineer Will look at these statistics and expect them to be duplicated When the measurements are done by the engineer himself. Otis> For Dr. Judy, it is truly a case of "my mind is made up - don't Confuse me with the facts. Otis> With all due respect -- you seem to not understand the difference between an analytic (what if ...) study, study to resolve certain issues and difficulties. Otis> The "downward" movement for all natural eyes (population average) is -1/3 diopters per year at the military academies. Otis> If you can demonstrate that the plus lens stops this downward movement, i.e., the control group goes down by the -1/3 diopter per year, while the test group shows no change, i.e., 0.0 diopters, then you will have a good INDICATION that you are on the right path, and that you should continue. Otis> As per the statistical analysis posted on my site, it is possible that the null hypothesis MIGHT be true, i.e., that there is no relationship between the visual environment and the refractive status of the natural eye. Otis> This is YOUR HYPOTHESIS DR JUDY. Otis> This statistical test MIGHT PROVE YOUR HYPOTHESIS, that environment has NO EFFECT on the refractive status of the natural eye. Otis> If it does, then that would wrap up the study, and we could all go home happy. Otis> But, in the world of engineering, you must propose these engineering-scientific studies to "shake out" the various ideas that exist about true prevention. Otis> A study of this nature HAS NEVER BEEN CONDUCTED. Otis> Given highly self-motivated engineers of like analytic capability -- I believe that this first step would succeed. Otis> But then, I do not have to deal with a great mass of the population that walks in off the street. Otis> That is the difference between optometry and engineering -- with all due respect. Best, Otis "Dr Judy" <mpace99nospam@rogers.com> wrote in message "Otis Brown" <otisbrown@pa.net> wrote in message Dear Friends, Otis> I would have no problem working on true-prevention among engineer-pilots who need to protect their distant vision. Otis> I am certain they would understand the nature of the scientific testing -- and I would expect them -- as engineers -- to take a leadership position in this proposed study. Judy> Otis had no results, he didn't actually do the study. Otis> I prepared the format of study for planning purposes and review by the pilot-engineers. The matter of execution can come later. Success favors a prepared mind. Judy> made up group averages that might be found (no individual data) and then did the statistical calculation on the made up data. Judy Otis> Judy has every right to state her opinion. Judy> My opinion??? I think it is a fact that you did not do a study and that you made up results that might be found if a study might be done, and then you did the stats on the made up data and found it to be significant. Dr Judy > 1. Clearly state the "null hypothesis" that there is no > relationship between the visual environment and the > refractive status of the natural eye. Studies show a relationship between myopia and near work. Why do you want to re-invent that wheel? What you call "visual environment" has several components. Real scientists wonder whether the relationship is attributable to accommodation, or convergence, or relative distance magnification, or "awareness of nearness," which are the only identifiable components of "visual environment". > 2. Each individual in the study must understand college-level > statistics, and the concept of significance levels. Nonsense. In real science, experimental subjects don't interpret the data, in fact they are kept naive whenever possible. > 3. It is possible that the null hypothesis might be confirmed. > That could be the goal of this type of study. It would be > wise to confirm this truth as quickly as possible. Then you can go home. We already know there is a relationship between myopia and near work. > Analytical statistics can do that for you -- if properly > used. > 4. The statically analysis I provided will confirm this in about > eight months. First you should take time to read the studies that have already proven a relationship between myopia and near work. > 5. But to be honest, the pilot using the plus must use it with > great force. (i.e., for all close work, and he must read at > the "blur point". Suddenly you adopt a new null hypothesis. You're not investigating the causative association between myopia and near work. The new H1 hypothesis is "plus lenses interrupt the progress of myopia." You are also fond of expressing another H1 - "minus lenses accellerate the progress of myopia". Each of these H1s require a different experiment. Pseudoscience "research" is invariably sloppy. > Beyond that there is not too much to say, other than 99.9 > percent of the population will not take intelligent use of the > plus at the threshold seriously. Pseudoscientists invent their own vocabulary in which many terms lack precise or unambiguous definitions, and some have no definition at all. Please define "intelligent use" and "the plus" and "the threshold". > Below is some more "OD opposition" to this concept of honestly > testing the natural eye (as an auto-focused camera), and > confirming the null hypothesis. Pseudoscientists invent their own vocabulary in which many terms lack precise or unambiguous definitions, and some have no definition at all. Please define "natural eye". > The ODs on sci.med.vision then insist that I perform this > test on humans -- knowing full-well that I, as an engineer can not > do the above test. Nonsense. We insist you read the human research that _is_ available before you contradict it with imaginary results. Existing human research confirms the second null hypothesis - plus lenses are not substantially effective at interrupting the progress of myopia. You should actually read the existing research before shouting that "STUDIES OF THIS NATURE HAVE NEVER BEEN PERFORMED." > Beyond a certain level this becomes a "head game", where they > hold "all the cards", and I am expected to play into a "stacked > deck". You set yourself quite a task. It's tough to disprove accepted science. Pseudoscience appeals to false authority, to emotion, sentiment, or distrust of established fact. > The "game" is of course that they are always "right" and > everyone else is always "wrong". Yes, I understand the game of > power and "position". It is a shame that so many intelligent > people fall victim to this "game". Pseudoscience appeals to false authority, to emotion, sentiment, or distrust of established fact. -MT snip > Catch-22: > > As an engineer I can test all eyes (except humans). I can > verify everything except for the above test. You can test human eyes for the purpose of conducting a study, providing you meet the human research standards of the research centre. You can't test human eyes for the purpose of prescribing glasses for a patient unless you are a licensed optometrist or doctor, but there is no prohibition about testing for research purposes. > The ODs on sci.med.vision then insist that I perform this > test on humans -- knowing full-well that I, as an engineer can not [quoted text clipped - 8 lines] > hold "all the cards", and I am expected to play into a "stacked > deck". We don't ask that you personally do studies to prove or disprove your ideas, we have only asked that you provide published evidence (which could be done by others) for your ideas. snip > Dear Judy, > [quoted text clipped - 11 lines] > Will look at these statistics and expect them to be duplicated > When the measurements are done by the engineer himself. I don't appreciate you taking my statements out of context. The quote from me was in reference to someone else asking for the raw data in your experiment. I pointed out that that experiment had not been done yet, it was a proposal only with a suggested statistical analysis of the data that might be found. Here is your starting comment in the first post of the thread from which you took my quote: "Here is a proposal to study the dynamic behavior of the natural eye. The study consists of a homogeneous group of people who have natural eyes." Note the word "proposal" ie, no study done yet. And you yourself state: Otis> A study of this nature HAS NEVER BEEN CONDUCTED. So if you yourself say the study was proposed and not yet conducted and then you run the statistics for the not done study, why am I wrong to say that there was no study and no data? > Otis> If you can demonstrate that the plus lens stops this > downward movement, i.e., the control group goes down by the > -1/3 diopter per year, while the test group shows no change, > i.e., 0.0 diopters, then you will have a good INDICATION > that you are on the right path, and that you should Yes, if a published study demonstrated that the use of plus lens at near prevents myopia, then we would believe it. So far, the published studies using plus at near have not found that it prevents myopia. Dr Judy Dear Judy, I will respond in greater detail, since I would be willing to lead a PURE engineering study of the nature that I proposed. A person normally only believes his own measurements -- finally, when push-comes-to-shove. If a person with great motivation, and technical skill, with intellectual preparation, sees the results himself, where he PERSONALLY controled all measurement, then I think the he will belive the results he achieves. Since in this proposed study: 1. All allowed in will PREVIOUSLY have had 20/20 vision. 2. Will PASS the Florida DMV test, i.e., vision of 20/40 to 20/50. 3. Will sign an agreement about their PERSONAL control of the study. 4. Will be taught how to use a trial-lens kit. Since NO PRESCRIPTION is going to be used, it follows that this is a PURE measurement study. Therefore there should be no objection to it. If the pilot concludes that he is going in the "right direction" and will succeed (i.e., stop the -1/3 diopter change in his eyes), then the program could be a continued program at these flight schools. Best, Otis Engineer ******** > snip > [quoted text clipped - 76 lines] > > Dr Judy > Dear Judy, > [quoted text clipped - 26 lines] > that this is a PURE measurement study. Therefore > there should be no objection to it. Whether or no prescribing is done or not has no bearing on "objections" to it. If you do the research at an university, they will have an office of human research and they will have guidelines that must be followed when doing human research. If you expect to publish the research in a referred scientific journal, the journal and the reviewers will have expectations about the quality of the study design and those expectations will not depend on whether or not prescribing is done. If you expect people to believe and accept your results, then you will need to meet the expectations and requirements of the Office of Human Research and the journals. Any objections to your study will be based on faulty design, not on whether prescribing was done or not. (Since you now say you are willing to do the study, can I assume you are agreeing that you have not done it yet and the statistics you posted earlier were based on hypothetical data?) Dr Judy > If the pilot concludes that he is going in the > "right direction" and will succeed (i.e., stop [quoted text clipped - 89 lines] > > > > Dr Judy > A person normally only believes his own measurements -- finally, > when push-comes-to-shove. Right.. measuring your own blood pressure is always more accurate than what they do in the doctor's office. -MT > > A person normally only believes his own measurements -- finally, > > when push-comes-to-shove. [quoted text clipped - 3 lines] > > -MT Dear Mike, As always, you love to "twist" my words. A person of high motivation, WITH THE RIGHT EQUIPMENT AND PRACTICE and make measurements as accurate, and would duplicate the measrements made in an office. The "kicker" is the time it would take to train a person to make "blood pressure" measurements accurately -- but it could be done. You might as well say "weight". Can a person measure his weight as accurately as a nurse does in an office. OF COURSE HE CAN. You imply he can not. That he why we disagree. Best, Otis Engineer > As always, you love to "twist" my words. No, I'm forced to point out your ignorance because you refuse to accept standards of practice we all consider "established". > A person of high motivation, WITH THE RIGHT EQUIPMENT AND PRACTICE > and make measurements as accurate, and would duplicate > the measrements made in an office. I mentioned blood pressure for a very specific reason. It's a "heisenberg" problem where performing your own test inevitably influences the result. It's absurd to conduct science this way. > The "kicker" is the time it would take to train > a person to make "blood pressure" measurements > accurately -- but it could be done. Again we address the problem of ignorance. Taking your own blood pressure influences the outcome. No legitimate journal would accept a study where subjects measured their own blood pressure, except by automated instruments. THAT could be done quite well, but you don't like autorefractors. > You might as well say "weight". > > Can a person measure his weight as accurately as > a nurse does in an office. > > OF COURSE HE CAN. Again ignorance. Weight doesn't change when you measure it yourself. Blood pressure and refraction do. -MT > > Right.. measuring your own blood pressure is always more accurate than what > > they do in the doctor's office. That's true for me. My blood pressure is always higher when the nurse first takes it. When the doctor says that it's too high, I explain that, and the doctor takes it, and it's almost always down. It wasn't down far enough last time, though, so he wants me to come in and have it taken again. > The "kicker" is the time it would take to train > a person to make "blood pressure" measurements > accurately -- but it could be done. Taking your blood pressure at home is trivial. For a few dollars you can buy a machine that does everything but pump the cuff. For a few dollars more you get that too. > You might as well say "weight". > > Can a person measure his weight as accurately as > a nurse does in an office. Home scales are notoriously inaccurate.  SignatureDan Abel Sonoma State University AIS dabel@sonic.net |
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