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Medical Forum / General / Vision / October 2005Why are so many people myopic?
To the eye professionals out there......does the evidence suggest that people always had such poor vision throughout history and just didn't realize it or are we doing things that are degrading our vision and contributing to its worsening performance. > To the eye professionals out there......does the evidence suggest that > people always had such poor vision throughout history and just didn't > realize it or are we doing things that are degrading our vision and > contributing to its worsening performance. Which type of "poor vision." Do you mean myopia, astigmatism, presbyopia? There is evidence for both, and evidence for breeding effects. -MT >> To the eye professionals out there......does the evidence suggest that >> people always had such poor vision throughout history and just didn't >> realize it or are we doing things that are degrading our vision and >> contributing to its worsening performance. > > Which type of "poor vision." Do you mean myopia, astigmatism, presbyopia? I'm particularly interested in myopia since that is my problem. It does seem to be the predominate vision problem in our eyes as we start out in life. There is evidence for both, and evidence for breeding effects. > Please explain: breeding effects. > I'm particularly interested in myopia since that is my problem. It does > seem to be the predominate vision problem in our eyes as we start out in > life. You're under the impression that myopia is common at birth? And predominate -> predominant. >> Please explain: breeding effects. Over time, a population may self-select for or against myopia. -MT > >> To the eye professionals out there......does the evidence suggest that > >> people always had such poor vision throughout history and just didn't [quoted text clipped - 10 lines] > > > > Please explain: breeding effects. You are incorrect. The predominant refractive error is hyperopia as we start out in life. More vision is lost to amblyopia arising from undetected and uncorrected hyperopia than is lost to myopia. Of all refractive errors, only hyperopia is correlated with reading disabilities. Why not join us in preventing those problems as they are preventable through early intervention? Unfortunately, most states in the U.S. continue to rely upon an inefficient detection system comprised of pediatricians and school nurse's aides. DrG What do you mean by "degrading our vision and contributing to its worsening performance"? DrG > To the eye professionals out there......does the evidence suggest that > people always had such poor vision throughout history and just didn't > realize it or are we doing things that are degrading our vision and > contributing to its worsening performance. What do you mean by "degrading our vision and contributing to its worsening performance"? > DrG > > Please don't snip the thread. I meant that large proportion of our young society needs myopic correction. They don't need help with their hearing, or coordination or smell or touch. I wonder if its always been that way for the past few hundred years. I would suspect not. I would suspect that modern man is doing something to degrade our vision. Joe> I meant that large proportion of our young society needs myopic correction. They don't need help with their hearing, or coordination or smell or touch. I wonder if its always been that way for the past few hundred years. Joe> I would suspect not. I would suspect that modern man is doing something to degrade our vision. Otis> BINGO! Well, when you and Otis figure out the cure for the ills of modern society (other than handing out free reading glasses), ring me up, please. DrG Dear DrG, Joe (GG) must be concerned with HER OWN VISUAL WELFARE. She is not concerned with the "ills of modern society" any more than you are. It is obvious that if GG figures this out (and checks her own eye chat, then she has no need for ANYTING that you might have to offer. Maybe that is the final resolution for her. If she can function with out the minus -- and that is no "impact" for her -- then why not. Her "mono-vision" is actually going to be of considerable help for her in the future years. >From what she says, I suspect her eye chart is about 20/50, and if she keeps this up, I would suspect the possiblity of getting to 20/40, which would pass most DMV tests. The rest, as they say, is up to her -- and not you. Best, Otis > Joe (GG) must be concerned with HER OWN VISUAL WELFARE. Then why is she posting here? DrG You notice the myopes more because they need correction to see distance. Most people (over 50%) on the planet with refractive errors are hyperopic. We just don't need glasses as youngsters since we can accommodate the error internally. We still have a refractive error that compounds in later life. We will never be able to take our glasses off to read something. Our vision is far better than most other animals. Carl >> To the eye professionals out there......does the evidence suggest that >> people always had such poor vision throughout history and just didn't [quoted text clipped - 11 lines] > few hundred years. I would suspect not. I would suspect that modern > man is doing something to degrade our vision. >> To the eye professionals out there......does the evidence suggest that >> people always had such poor vision throughout history and just didn't [quoted text clipped - 11 lines] > few hundred years. I would suspect not. I would suspect that modern > man is doing something to degrade our vision. Reading. > [ ... ] > Reading. Yeah, probably. But why? Stretching something beyond its elastic limit? Maybe there is a long term accommodative mechanism where stretching adapts eyes to their particular use (reading, scanning the horizon, whatever). I used to like to think that the ciliary muscle (which is circular, roughly) stretched the suspensory ligaments in order to allow the lens to round up to accommodate for near vision. But that apparently is not quite right. But I still can guess that something like that is going on. For myopia occasioned by close work, some eye structure is stretched to a point that it cannot bounce back all the way. Made worse by boosting negative correction. There is a theory for that. Fit kids with a tendency towards myopia with reading glasses, maybe prisms to correct convergence appropriately. I like that theory. But too late to try that now. Maybe us progressive myopes have the situation complicated by a collagen deficiency, so that whatever retention keeps our god-given lenses relatively flat goes easily flabby when continually and progressively stretched. Well, now I know that I have very long eyeballs, and that is certainly a factor as well, not to mention presbyopic hardening of the lenses. Still trying to figure. Heck, might turn up again as a myope next time around. -- Dick Adams Life-long myope, better now with implants. > > [ ... ] > [quoted text clipped - 34 lines] > Dick Adams > Life-long myope, better now with implants. Just curious about how much reading you have done on the topic outside of this NG? Alternative mechanisms have gained favor. DrG > [ ... ] > Just curious about how much reading you have done on the topic outside > of this NG? Alternative mechanisms have gained favor. I just checked out this group for the first time several days ago. I started thinking about this in 1944, at the age of 15, becoming myopic. Since then, I have received education in life sciences, physics (including optics), and have done salon photography, electron microscopy, and analytical light microscopy including microspectrophotometry (doctoral thesis). Unfortunately, I have never analytically dissected any eyes. Certainly, I am not qualified as an optical practitioner. I think one should be as suspicious of "alternative mechanisms" as of the usual views.  SignatureDick Adams <firstname> dot <lastname> at bigfoot dot com > I think one should be as suspicious of "alternative mechanisms" as of the > usual views. Critical analysis is supposedly something that is a byproduct of a university education. So, if you mean that one should apply this to any and all proposals, I agree. However, I disagree with your statement at face value. Every new study that is published in a peer-reviewed journal is required to have a bibliography and a review of the literature published to date, in order to show relevance and originality. Additionally, the article is subject to peer review by the editorial board. The result is that research is designed to shed new light on a topic, or tie up loose ends in order to make understanding more comprehensive. If you had read the literature, you would have understood how incompletely the theory of accommodation explains myopiagenesis, as myopia can be demonstrated to occur in the complete absence of accommodation. Investigators are now looking more closely at the concept of retinal image quality as a stimulus to changes occurring at the level of the retina. But, no theory yet has been found to tie-up all the loose ends. DrG > To the eye professionals out there......does the evidence suggest that > people always had such poor vision throughout history and just didn't > realize it or are we doing things that are degrading our vision and > contributing to its worsening performance. Don't know about the history of poor vision, but these days we spend a lot more time doing near work (reading, computing, etc) than our eyes were 'designed' (evolved) for. This may contribute to myopia in particular, but also it may make other existing problems like hyperopia or astigmatism more noticeable due to the demand of the task. I don't know for a fact but would strongly suspect that hundreds of years ago there was a lot less myopia and perhaps less astigmatism than there is now. To be highly myopic back then would have been more than an inconvenience. To loosely quote Brien Holden: in the world of fauna, you're either emmetropic or dead. In years gone by, I'd say this would have applied to humans too. Dom Study after study finds that close work is a factor, second only to genetics. I think the incidence is going up, but primarily due to the excessive amount of computer usage among young people. I have been taking my own informal "show of hands" at the middle school for the past twenty years, and it seems like more hands go up now than in the past. Also, at some point, when vision requirements for operating a motor vehicle and school screenings became mandatory, the detection rate improved. DrG >> To the eye professionals out there......does the evidence suggest that >> people always had such poor vision throughout history and just didn't >> realize it or are we doing things that are degrading our vision and >> contributing to its worsening performance. The answer to this one is going to mostly speculation, since there are no records of the distribution of refractive error in the population beyond about 100 years back. We can speculate that some myopia must have been around if older people did any near work. The educated classes (monks, scribes) and the artists would have found myopia to be an advantage. > Don't know about the history of poor vision, but these days we spend a lot > more time doing near work (reading, computing, etc) than our eyes were [quoted text clipped - 12 lines] > emmetropic or dead. In years gone by, I'd say this would have applied to > humans too. Not so sure about that. Humans have divided labour for thousands of years. The hunters and warriors would need good distance vision, but the food gatherers, baby minders, tool makers, artists, clothing makers and so on would find keen near vision a boon. Dr Judy > Dom >>> To the eye professionals out there......does the evidence suggest that >>> people always had such poor vision throughout history and just didn't [quoted text clipped - 32 lines] > > Dr Judy Interesting theory - I wonder if there is a statistic correlation between artistic people (painters, writers, ...) and people with myopic vision since birth. > Interesting theory - I wonder if there is a statistic correlation between > artistic people (painters, writers, ...) and people with myopic vision > since birth. Very, very few people are born nearsighted. -MT >> Interesting theory - I wonder if there is a statistic correlation between >> artistic people (painters, writers, ...) and people with myopic vision [quoted text clipped - 3 lines] > > -MT I've been wearing glasses since my first year in school (6 years old) - now i'm 33 (male) and -9.5/-10 (wearing contact lenses now). Guess i'm born myopic, but it's strange since there are no other people like me in the family. My mother was smoking when she was pregnant, could that have caused it ? I also have a lot of birthmarks. >> MT> Very, very few people are born nearsighted. > > I've been wearing glasses since my first year in school (6 years old) - > now i'm 33 (male) and -9.5/-10 (wearing contact lenses now). Guess i'm > born myopic It's rare. In general, those who start developing it early are the ones who get into double-digits (-10). And they're often excluded from "myopia" studies because there are frequently other problems, suggesting a different cause or mechanism. Many of them had high fevers in early life. > but it's strange since there are no other people like me in the family. My > mother was smoking when she was pregnant, could that have caused it ? I > also have a lot of birthmarks. I don't know of any association.between maternal smoking and myopia. -MT >>>> To the eye professionals out there......does the evidence suggest that >>>> people always had such poor vision throughout history and just didn't [quoted text clipped - 36 lines] > artistic people (painters, writers, ...) and people with myopic vision > since birth. Most people are not myopic from birth but develop it during one of the two childhood growth spurts (one around age 6/7, the other around puberty). Don't know about occupations but there is a correlation between higher IQ and myopia. Dr Judy > Don't know about occupations but there is a correlation > between higher IQ and myopia. Drat, I'm a hyper. Hopefully my AB neg. blood has added to what little IQ I have. (just kidding... I think. Was there a correlation in the other direction?) -Quick Dear Quick, Subject: Refractive status and intelligence. I think it goes this way. Ref: IQ +2 80 +1 90 0.0 100 -1 110 -2 120 -3 130 -4 140 -5 150 -6 160 It has been proven that you can take the primate eye and get its refractive status to "move" in a negative direction. Thus we now have a new tool to make primates more intelligent. With a series of "increments" in minus-lens strength, you could probably create a primate with -6 diopters and therefore an IQ of 160. They do not call "man" the intelligent ape for no good reason. Best, Otis > Dear Quick, > > Subject: Refractive status and intelligence. I hope this was your attempt at humor. If it is, you are so very strange. If it was not, you are a very sick man. > In article > <1128360287.621131.80670@g49g2000cwa.googlegroups.com>, [quoted text clipped - 5 lines] > I hope this was your attempt at humor. If it is, you are > so very strange. If it was not, you are a very sick man. Hmmm, I really like being able to count the leaves of the tree line on the mountain top. I haven't decided yet if I want to trade this ability for a brain. what to do... I get so confused with decisions. -Quick Dear Larry-Doc, I think that Quick has the "Quick-intelligence" to understand the humor in this -- even if you do not. Best, Otis in your previous post you blurted out the following nonsense: "It has been proven that you can take the primate eye and get its refractive status to "move" in a negative direction." why does this study, performed on HUMANS rather than monkeys or chickens, contradict your "minus stairstep" proposal? -- Goss, D. (1984) Overcorrection as a means of slowing myopic progression. Am J Optom Physiol Opt., Feb;61(2):85-93. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstra ct&list_uids=6703013&query_hl=3 Thirty-six subjects (18 males and 18 females) ranging in ages from 7.38 to 15.82 years received an overcorrection of 0.75 D over the power required to correct their myopia exactly. These 36 experimental subjects were matched by control subjects selected at random from the files of the Indiana University Optometry Clinics. The criteria used in matching were sex, beginning age, beginning refractive error, and duration of time covered by the record. The mean rate of change of refractive error for the experimental group was (minus indicating increase of myopia) -0.49 D/year (range, +0.37 to -1.95 D/year) on retinoscopy and -0.52 D/year (range, +0.21 to -1.32 D/year) on subjective refraction. The mean rate of change for the control group was -0.47 D/year (range, +0.06 to -2.03 D/year) on retinoscopy and -0.47 D/year (range, +0.28 to -1.72 D/year) on subjective refraction. Rates for the experimental and control groups were not significantly different. -- Otis--this reference was presented to you previously as has countless other study results. why do you continue to ignor the overwhelming evidence against you? what kind of a rational person are you? you seem to have some sort of evangelical faith in your beliefs that is not at all based in science or objective thinking. Dear "P.Clar" Subject: The primate studies make the natural eye's behavior FINAL in a scientific sense. If you RESPECT the natural eye as a well-designed control system -- and the entire population of natural primate eyes -- the ability of the natural eye the change its refractive state to a "negative change" in the accommodation signal -- is proven in a scientific sense. It is true that "translating" preception of scientific truth to a "practical" solution (by prevention) is indeed difficult -- and will depend on the motivation of the person himself. Indeed HIS preception of what he wants in his life -- and whether he has that type of personal interest. If he does then the "human-primate" studies (Oakly-Young) show the results of a "proper-strength" plus lens -- when "correctly used" BUT THE PERSON HIMSELF. This means that indeed, "preception" and control are indeed transferred to the person himself. The Oakley-Young show what is possible. But the difficulty is indeed that most people prefer that "instant solution" to the intellectual judgment and the need to make the use of the plus a "habit". I respect the design and behavior of my natural eyes. And I respect the difficulties of prevention -- and I suggest that people like Georgeous and others supported by Steve Leung OD have begun to figure this out. Keep an open mind on the subject of the natural eyes proven performance. This conceptualization could help some to learn to accept the use of the plus -- as the second opinion. One thing the Oakley-Young study does establish -- that the use of the plus must START before the minus lens is applied. Best, Otis > It is true that "translating" preception of scientific > truth to a "practical" solution (by prevention) is > indeed difficult -- and will depend on the motivation > of the person himself. Indeed HIS preception of > what he wants in his life -- and whether he > has that type of personal interest. It's called drawing the wrong conclusions from the data, and selective inclusion of the data. It's intellectual dishonesty. True scientists get fired for it. DrG > Subject: The primate studies make the natural eye's > behavior FINAL in a scientific sense. At least until somebody makes measurements on humans. > If you RESPECT the natural eye as a well-designed > control system -- and the entire population of natural > primate eyes -- the ability of the natural eye the > change its refractive state to a "negative change" > in the accommodation signal -- is proven in > a scientific sense. Under all conditions, at all ages, the same in all species. > The Oakley-Young show what is possible. If you're a young, esophoric myope. How many are? -MT in your previous post you blurted out the following nonsense: "It has been proven that you can take the primate eye and get its refractive status to "move" in a negative direction." why does this study, performed on HUMANS rather than monkeys or chickens, contradict your "minus stairstep" proposal? Gross's sample size "n = 18" was way to small to have any meaningful scientifc results or meaning. The Oakley Young study was done with over 250 chidren carried out for SEVERAL YEARS. The Oakley-Young study is far more accurate in confirming the dynamic behavior of then natrual eye that the n=18 study. Get real! Otis i believe that sample size in the Goss study is n=36. statistical analysis using this sample size showed no difference in myopia progression between the overminused group (n=36) and the control group (n=36). the statistical analysis takes into account the sample size, and still produces a clear result. you cannot refute that results since statistics take into account the number of observations and the sample variability. the study demonstrates excess minus does not result in increased OR decreased myopia-- period! and i guess you still don't understand that the original Young study included a large number of esophoric myopes. i thought it was clearly explained enough, even for you, that esophoric myopes are very likely accommodative myopes. these are not true anatomical myopes. why isn't the minus stairstep effect demonstrated in the Parsinnen study? how come the Chung study showed GREATER progression of myopia when LESS minus lens power was used? otis, you are so clearly wrong that it's hilarious. just give up. > Otis--this reference was presented to you previously as has countless > other study results. why do you continue to ignor the overwhelming > evidence against you? There are fatal flaws in every study that disagrees with Otis. -MT (stop cascading) > Most people are not myopic from birth but develop it during one of the two > childhood growth spurts (one around age 6/7, the other around puberty). > > Don't know about occupations but there is a correlation between higher IQ > and myopia. what about astigmatism? |
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