Nearsightedness Increasing in U.S.
Tim Campbell
time in decades I was able to pass the vision test without wearing
glasses. The clerk asked, "Are you wearing contacts?" I said, "No."
She then asked, "Have you had that surgery?" I said, "No I have just
been eating mostly fruits and vegetables for a long while."
My vision definitely deteriorates when I venture away from the
produce
aisle in the grocery store or am eating mostly restaurant food. And
improves when I eat a diet largely centered around fruits and
vegetables and a few grains.
Tim
Nearsightedness Increasing in U.S.
By Nathan Seppa, Science News
December 15, 2009 |
This broad survey showed that 25 percent of those examined in the
early 1970s were deemed to be nearsighted, compared with 42 percent
examined three decades later, the researchers report in the December
Archives of Ophthalmology. That’s an increase of 66 percent.
Myopia severity also increased, with moderate nearsightedness
doubling
between the two time periods and severe cases, although uncommon,
also
rising sharply. Mild myopia cases increased slightly, from about 13
percent to 18 percent. This group included some people who did not
need corrective lenses, says study coauthor Susan Vitale, an
epidemiologist at the National Eye Institute in Bethesda, Md.
Among blacks, the overall myopia rate was lower than in whites but
still jumped from 13 to 34 percent over the three-decade span.
When analyzing the more recent eye-exam data, the scientists used
only
diagnoses that were made with the same technology used in the 1970s —
mainly standard eye tests and trial lenses. Including diagnoses made
with more advanced technology that has become available only recently
might have biased the comparison, Vitale says.
The cause of nearsightedness is poorly understood. Past research has
linked added risk to both a genetic predisposition to nearsightedness
and to excessive amounts of near work, the kind of tasks that require
peering at written words or small objects.
"Some people would say near work is a reasonable explanation," Vitale
says, particularly with the advent of video games and other
electronic
devices. Children also spend less time outdoors than they once did,
she says. And some researchers contend that more outdoor time means
seeing in better light, focusing farther.
The nature of near work has changed dramatically in the past 30
years,
says Jane Gwiazda, a psychologist at the New England College of
Optometry in Boston who researches vision problems. But while near
work probably accounts for some of the myopia increase, it’s been
difficult to pinpoint the specific detrimental aspect of near work
that’s to blame because the nature of such close work varies. Some
people take frequent breaks or have better lighting than others.
"There are lots of factors there," Gwiazda says.
Meanwhile, compelling data link a lack of outdoor time with increased
myopia risk, she says, with questionnaire-based surveys finding that
children with myopia spend less time outdoors. "Some people think
that
more distance viewing sends a signal to the eye to stop growing," she
says. Nearsighted eyes tend to be elongated. Natural light might also
stimulate dopamine production, which is known to inhibit eye growth,
she says, and extra vitamin D from the sun might contribute to
regulating eye growth.
As for hereditary factors, research shows some added risk for
children
born to nearsighted parents. "It might be that somehow the population
has changed and that there are more people floating around that have
more genetic risk," Vitale says.
Editor’s note: This post was updated to include comment from a
researcher not involved with the study.
http://www.wired.com/wiredscience/2009/12/nearsightedness-increasing/...
Neil Brooks
> Note: The last time I had my driver's license renewed, for the first
> time in decades I was able to pass the vision test without wearing
> glasses. The clerk asked, "Are you wearing contacts?" I said, "No."
> She then asked, "Have you had that surgery?" I said, "No I have just
> been eating mostly fruits and vegetables for a long while."
>
> My vision definitely deteriorates when I venture away from the
> produce
> aisle in the grocery store or am eating mostly restaurant food. And
> improves when I eat a diet largely centered around fruits and
> vegetables and a few grains.
[snip]
Eating a well-balanced, varied diet, replete with grains, fruits, and
veggies ... has very little downside.
Mike Tyner
There are long trends, but rarely more than a quarter-diopter of change day
to day.
One such well-known trend is for adults 30-60 to shift gradually in the
farsighted direction, which means _improvement_ if you happen to be
nearsighted. But it's quite gradual, years in the making.
When "overnight" changes of a half-diopter or more happen in both eyes
simultaneously, it's usually due to elevated blood glucose, and resolves
when the BG comes down.
Sometimes the change is dramatic, 2 or 3 diopters. But it's not important
which direction, nearsighted or farsighted. If it's a half-diopter or more
in either direction, get your BG checked.
-MT, OD
"Tim Campbell" <tvn...@gmail.com> wrote in message
news:0780c4b7-e7cf-414c...@1g2000vbm.googlegroups.com...
Otis
Dear Tim,
Congratulations on you Snellen clearing by your method.
The increase of myopia might be due to the chronic over-prescription
of a minus lens.
Prevention best,
Neil Brooks
> Dear Tim,
>
> Congratulations on you Snellen clearing by your method.
>
> The increase of myopia might be due to the chronic over-prescription
> of a minus lens.
But there doesn't seem to be any evidence for that.
Mike Tyner
"Otis" <otis...@embarqmail.com> wrote
> The increase of myopia might be due to the chronic over-prescription
> of a minus lens.
FRAUD.
Otis
Dear Mike,
There is a BIG difference between "MIGHT" and "IS".
Hope you understand.
Otis
On Dec 17, 12:51 pm, "Mike Tyner" <mty...@mindspring.com> wrote:
> "Otis" <otisbr...@embarqmail.com> wrote
Mike Tyner
"Otis" <otis...@embarqmail.com> wrote
> There is a BIG difference between "MIGHT" and "IS".
So now you say minus lenses "might" be over-prescribed?
-MT
Otis
Dear Mike,
In an excellent scientific study (not "clinical") I think the
insighful Engineer could establish this truth himself, PROVIDED he had
the scientific tools (and the motivation) to make the objective
measurements himself.
But only the future will tell us if that SCIENTIFIC (not medical)
PREVENTION study will become possible.
Obviously your "bias" will prevent any competent Scientific prevention
study from even taking place -- in the first place.
Enjoy,
On Dec 17, 10:41 pm, "Mike Tyner" <mty...@mindspring.com> wrote:
> "Otis" <otisbr...@embarqmail.com> wrote
Mike Tyner
"Otis" <otis...@embarqmail.com> wrote
> In an excellent scientific study (not "clinical") I think the
> insighful Engineer could establish this truth himself, PROVIDED he had
> the scientific tools (and the motivation) to make the objective
> measurements himself.
No question. Please come back and tell us when he's done it.
Until then, -3 myopes get -3 lenses.
-MT
Otis
will be OVER-PRESCRIBED BY YOU BY AT LEAST -2 DIOTPERS.
The reasult, of course, will be stair-case myopia for the child who
gets this over-prescription and wears it all the time.
Second-opinon (and true-prevention) best,
On Dec 17, 10:51 pm, "Mike Tyner" <mty...@mindspring.com> wrote:
> "Otis" <otisbr...@embarqmail.com> wrote
Tim Campbell
> Eating a well-balanced, varied diet, replete with grains, fruits, and
> veggies ... has very little downside.
Yes, and as I have repeatedly experienced, a definite vision-related
upside...
...and I have my new "no corrective lenses required" driver's license
to prove it.
Neil Brooks
> Until then, a person who can CONFIRM visual acuity of 20/40 to 20/50
> will be OVER-PRESCRIBED BY YOU BY AT LEAST -2 DIOTPERS.
Says you.
> The reasult, of course, will be stair-case myopia for the child who
> gets this over-prescription and wears it all the time.
Says you.
> Second-opinon (and true-prevention) best,
Fewer unsupported opinions, please, and more (read: ANY) evidence.
Neil Brooks
I agree with Dr. Tyner: get your blood glucose checked, if you're
seeing that wide a variance in your vision, AND if it seems to respond
to dietary improvement.
Jan
> The increase of myopia might be due to the chronic over-prescription
> of a minus lens.
>
> Prevention best,
Layman Otis I suppose your statement above is based on solid facts?
Or is it just another example of an unscientifically layman's behavior.
BTW, since you have no knowledge in the eyecarefield you may forget
your "prevention best".
Jan (normally Dutch spoken)
Tim Campbell
> > On Dec 16, 2:54 pm, Neil Brooks <neil0...@yahoo.com> wrote:
> I agree with Dr. Tyner: get your blood glucose checked, if you're
> seeing that wide a variance in your vision, AND if it seems to respond
> to dietary improvement.
Blood glucose is normal...Thanks though...