Does an emmetropic child induce myopia through excessive reading?
Does an emmetropic child induce myopia through excessive reading?
No! But some folks will have exercise programs, etc. to prevent this.
Myopia is all in the genes.
You got myoptic parents you most likely gonna be myoptic. Sometimes your grandparents can get you on or off the hook for this.
Chip
I remember many years ago in Optician's school one of our OD's relating how too much near work can over time cause myopia. The example that sticks in my mind is that the Eskimos' who grew up hunters were rarely nearsighted. Their children became nearsighted when mandatory schooling in small modular classrooms came into their way of life.Originally Posted by chip anderson
I could be wrong and if so I'll stand corrected.:)
Just remember back to some old school OD's that prescribed bifocals for all myopes. Right?? Wrong? I'll be dam#ed if I know. I believe that that was their theory as well.
When I was young I had a set of teeny round segs, they must have been 15mm in diameter.
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
I asked this question of 2 OD's and 3 MD's today, and got no answers: not a maybe, not a disagreement between doctors, nothing but a general discourse about myopia increasing with age. This used to be a burning issue some years ago, but not now I guess.
Many individuals prescribe bifocals for children to get more money for the lenses! They have a theory but basicly the theory has to do with payments on the condo. This does not include children with prescribed bifocals for strabismus, just the standard myoptic or hyperoptic kid.
The theory that nearsighted people are created by reading goes back to a century or more when nearsighted people did not have glasses, they were the tool makers and scholars. The farsighted ones were the hunters, seamen, etc.
The farsighted ones weren't qualifed for close work and the nearsighted ones were not qualified for long distance work. This is still evident a little today but we are in the business of changing this.
Was taught in one history class or another about a European king that kept myopes in a colony so they could make his jewelry and make future jewelry makers.
Chip
There is some evidence of increasing myopia in the population with increasing near work. There are too many factors to provide enough evidence to even change some peoples minds.
Chip, what about docs who sell bifocals for kids at the same price as sv. Seems the profit margin actually went down there. What about those ODs who refuse to put kids in PALs, and rather insist on bifocals. This is just another excuse for you to *****. :bbg:
You won't get anyone to agree on this. There is a whole lot of evidence that myopes tend to be more introverted. It depends who is doing the testing and who is doing the interpreting of all these studies.
I've read some articles of huge changes in some asian countries in the last few decades as their literacy rates have gone up.
There is a "stress" put on the visual system with prolonged near work. Can long term stress cause physical changes? Some researchers think so. There are some doing research to see if the accommodating muscles contracting causes IOP rises which stimulate axial elongation. The process is not well described.
You put a monkey in a room and not allow him to see far away, his eyes will elongate and he will become myopic. You stitch a cat's eyes together and they don't go through the normal emmetropization process. Would you like to try this on your children? I bet not. Its hard to extrapolate to humans. Its hard to get monkeys to read.
I think the answers are staring at us, but no one yet has asked the right questions. And, typically its hard to get approval to lock kids in rooms for 10 years at a time, or force them to read continuously for months on end, or force them to not ever do near work....
What about todays kids doing all that text messaging and computer work? Do you feel that it is ruining the muscles in their eyes? Lately our office has seen more teen bifocal wearers, (do to accomadation problems) than I have seen in YEARS.
During accomodation, does the ciliary body contract or relax? If (repeat, if) these kids develop myopia, could it not be because their crystaline lenses are too convex from muscles not contracting, and the system now being unable to do so satisfactorily? And do we agree that any such induced myopia is unrelated to corneal changes that might produce myopia for ordinary reasons?
Orange:
On one point you and I agree. Not too sure that myopes re more introverted but young spectacle wearers are. The first 20 years or so of my career, I practically did nothing but fit contacts, mostly on teenage myopes.
Always found it very interesting to see these little shy introveted 14-16 year olds come in for contacts and when they returned for a two-week follow-up they had changed to little sexpots. So much make up on, so much skin showing, it was facinating.
Most went back to "average" (which was a little less of the above) withing six-months or so.
AS to the bifocals instead of progressives, especially in the strabismus patients all of the pediatric ophthalmologists I have known, have insisted on this with a very high wide straight seg. Now I have read on optiboards and elsewhere that some push progressives for this (don't know how many of these are board certified pediatric ophthalmologists though), an got the impression that all pushing progressives self-refer dispensing so I don't know how "pure" thier motives are.
Chip
I don't think anyone knows the answer for sure. I have heard that in some Asian countries it is normal to under correct myopia in hopes it will help slow it down. I swear I heard recently that a study done on it actually found it had the opposite effect but I can't remember where I read it.
I have always believed this to be true. I thought I was a good example. I am the only person in my family to wear glasses other than one aunt who is a hyperope. I was an intense little bookworm as a child and I wore glasses by age eight. I never increased beyond a minus 3.00 but still where else did it come from?
Hi all,
There's been some interesting studies on chicks, and how they develop myopia as a result of defocus which is the study that I believe that happy lady is talking about. This would suggest that a full correction for distance is a good idea for young progressing myopes. I think the suggestion that a lesser correction will stop the eyes from getting worse stems from the misperception that this is a muscle problem, not a physical axial lengthening problem.
re b/focals and children, I will only prescribe a bifocal if the following are true. a) a young, fast progressing myope, with eso at near. I'll give enough + to give them a nice 2-4 exo. I definitely do not do this routinely, however if I have a 10 year old, who's progressing at a dioptre a year, absolutely, I'll give it a go. Usually I tell the parents that there are studies to suggest that this MAY help to slow progression, but it might not work however really we have nothing to lose.
steff
From what I remember reading in an Optometry text while in opticianry school, there is something called Emmetropization. As I understand it, this when the eye adjusts it's refractive power over time during youth. In other words, if a child is slightly hyperopic or myopic at his/her's early years, then there is a good chance that the child will be emmetropic later on on life.
I guess you can theorize that if the child is emmetropic and spends most of the time focusing up close, then he/she may become myopic. This is why parents used to yell at us when we stood close to the TV. :)
Google is my friend.:) I found a reference to a study at Anglia Polytechnic University in Cambridge England testing if under correcting myopia would slow it down. The study was stopped by Daniel Leary O.D when it was showing the opposite effect. Under correcting myopia increased it faster in this study.
Of course those of us that fit PMMA for decade and did ten thousand case or more are convinced that a good well managed PMMA fit definitely retards or stops myopia in almost but not quite all cases.
Chip
Both my parents are hyperopic (and presbyopic at this point) and I am myopic. My Rx is about -5.00. For my own vision, I question the chicken or egg senario. My parents got me my 1st pair of specs around age 4 because they noticed me standing very close to the TV to watch Sesame Street (or whatever). Then as I grew up, I was a serious reader and my myopia got stronger and stronger (bifocals tried in 2nd grade to little avail) until it stabalized around age 20. My Rx hasn't changed much since then.
There has to be several issues at play.
My dad, brother and sister are all myopic. My mom wore glasses while in college and later now as she is presbyopic.
I spent most of my summers hiding up in a tree and reading a good book. Spent many nights reading when I was a child-young adult cause I found it a relaxing escape and refreshed me almost as much as sleeping.
I have one eye that is farsighted and plano in the other. Had some reading glasses in college. However as I have increased my time on the computer.. I have noticed that I need more help for near.. hence, my autographs..at age 36...*sigh*
"Some believe in destiny, and some believe in fate. But I believe that happiness is something we create."-Something More by Sugarland
Sometimes genetics go back further than the evident genes from the immeadiate parents.
Sad to say that someone in Illinois once did a "gene test" in "an average wasp neighorhood" and found that even amoung traditional families 2 in five children did not have the mother's husbands genes.
I suspect that you can check with any old practicing or retired ophthalmologist and you will find that they believe that almost all refractive error not due to trauma is genetic. Anyone want to contact some one like the American Ophthalmological Society, Or American Optometric Society and see what thier research on the subject indicates?
Don't think you will find anyone that knows anymore that thinks reading causes myopia, or hyperopia, or strabismus, or cataracts, or much of anything except possibly an enhansement of knowledge and maybe a little eye fatigue.
Chip
How about accommodative facility?
At 10 years old do you think it'll make a big difference?
(nice to see another Aussie though - I'm in Brissie)
steff
People do what is comfortable. An uncorrected myope is comfortable reading. Same kid is not comfortable bird watching or catching fly balls - because it's just not clear. Therefore they read. Myopia progresses during the growth years. Actually hyperopes become more myopic during the growth years too. I'm not saying anything that you guys don't know, I'm just thinking through this to design the study.
So the study needs to be amount of myopic progression vs amount of time spent reading without correction. The control group could be the hyperopic kids. (of course they don't like to read, so your control group is scarce). Now why would you have a kid that has been identified as myopic and then not correct them? Therein lies the problems with the study.
As a corralary to the myope who develops a lifelong love of reading by the time they are 10 years old - what percent of ADD kids are hyperopic? Seems to be 80% in my unscientific data gathering. Hmm, concentrating close-up is uncomfortable, but running around outside isn't.
After a wet refraction revealed my latent hyperopia is 2D at age 24, the doctor's comment was "You finished college?" (I actually did) I hadn't ever worn glasses. He continued "If you had worn glasses, you might have been able to go on to be a doctor." I think that was a compliment. What a jerk.
But his point was based on what he sees every day. I wonder what my hyperopia was when I was learning to read? 3D? 4D?
Yes I was ADD.
I would only prescribe a bifocal if the child was near eso AND symptomatic, or at least if there were a demonstrable effect on reading fluency. I certainly wouldn't promote bifocals for myopic kids as a way to retard progression.
There has been a recent study by Dr Kathryn Rose at the University of Sydney (www.fhs.usyd.edu.au/news_events/news/2008/sydney_myopia_study.shtml)
which may show a link between myopia progression and reduced amount of time spent outdoors in natural light. I understand this may be due to the affect of light on the release of the Dopamine, and its affect on axial length. This study suggest that there is little if any affect by close work on myopic progression (at least in children).
I think as optometrists, we have to be careful when advocating a particular approach that it has some scientific vailidity.
Go BLUES :bbg:
Fair enough,
I agree with the symptomatic, however I will also offer it as an option to a child who is progressing very quickly. If a child is progressing at 1-2 D a year and the parents (or child) is concerned I'll offer it an option. I will say that whilst there is a little research to suggest that it may help, the research isn't really good (and other studies have suggested that it doesn't retard progression), and in all reality the jury is out. Some parents want to try it regardless though. I'd never advocate it for every child myope though.
GO THE MAROONS!! (well, the Sea Eagles might have won the NRL, but the Maroons still took out the State of Origin)
steff
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