Bushnell's Fault!
Posted on 06/22/2011 2:36:23 PM PDT by nickcarraway
WHY is nearsightedness so common in the modern world? In the early 1970s, 25 percent of Americans were nearsighted; three decades later, the rate had risen to 42 percent, and similar increases have occurred around the world.
There is significant evidence that the trait is inherited, so you might wonder why our myopic ancestors weren’t just removed from the gene pool long ago, when they blundered into a hungry lion or off a cliff. But although genes do influence our fates, they are not the only factors at play.
In this case, the rapid increase in nearsightedness appears to be due to a characteristic of modern life: more and more time spent indoors under artificial lights.
Our genes were originally selected to succeed in a very different world from the one we live in today. Humans’ brains and eyes originated long ago, when we spent most of our waking hours in the sun. The process of development takes advantage of such reliable features of the environment, which then may become necessary for normal growth.
Researchers suspect that bright outdoor light helps children’s developing eyes maintain the correct distance between the lens and the retina — which keeps vision in focus. Dim indoor lighting doesn’t seem to provide the same kind of feedback. As a result, when children spend too many hours inside, their eyes fail to grow correctly and the distance between the lens and retina becomes too long, causing far-away objects to look blurry.
One study published in 2008 in the Archives of Ophthalmology compared 6- and 7-year-old children of Chinese ethnicity living in Sydney, Australia, with those living in Singapore. The rate of nearsightedness in Singapore (29 percent) was nearly nine times higher than in Sydney.
(Excerpt) Read more at nytimes.com ...
My wife and I are very nearsighted, but I cannot explain why our kids do not need glasses.
Being indoors more and more is only part of the problem. It’s what one does while indoors that makes a bigger impact on vision (i.e. being in front of computer monitors for hours on end, watching television constantly, etc.). Or, at least, that’s what I think.
I blame Congress. :)
For more than a hundred years it's been well known that you can go to a remote area where almost no one is nearsighted, introduce a certain function to them, and within 50 years near sightedness will be over 30%.
That function?
Reading.
Unfortunately, forcing your eyes to focus closely on the printed page has the effect of eventually making them longer. Groups that focus primarily at a distance, and have no real reason for close focusing, have practically no nearsighted members.
In all the parts of the world we've gone to "civilize" nearsightedness followed shortly thereafter.
As one who has worn glasses since I was 13, I do believe this whole piece is poppycock. We didn’t even have a tv until I was 15. And, I spent lots of hours in the sun. Balderdash!!!!!
So taking the children to the beach can save lots of money in optometrists at long term? Sounds good to me.
Bushs’ fault (couldn’t resist :-))
Bushs’ fault (couldn’t resist :-))
Nope. Sounds resonable — computers.
Nothing new under the sun?
BELOW is a transcript of pages 169-170 from the book TOTAL VISION which I read way back in the early 80’s .
Light, in addition to being necessary for vision, stimulates both the pituitary and pineal glands and possibly other regions of the mid-brain which control the endocrine system and the production of hormones. It is not only the portion of the spectrum which we can see that is important, but also the bands that are present but not visible to the naked eye. The process is not unlike the photosynthesis of plants. Without certain ultraviolet wavelengths human hormone production is altered.
Several researchers working at various medical centers and laboratories throughout the country have found that when any part of the natural sunlight spectrum is blocked from entering the eye for a long period of time, abnormalities may develop. Women living above the Aortic Circle, where the night goes on for three months at a stretch during the winter, are likely to become infertile then because they stop ovulating. When sunlight returns, so does fertility.
Perhaps the most startling relationship disclosed concerning limited-spectrum lighting is the linking to it of some types of cancer. At least a half-dozen animal studies have come up with the same conclusion: reduced spectrum lighting influences the growth and the incidence of some types of cancer. Anything other than the full spectrum appears to change the course of nature.
And when the few reports of remission of terminal cancer in humans are looked at, a connecting link in a number of the cases appears to be getting plenty of natural sunlight. The people decided to spend their last days outdoors in the sun. One such story was reported a dozen years ago in TIME magazine: the man quit going to his office and started reading in a rocking chair on his back porch and tending roses in his garden. His cancer disappeared.
In a 1959 study with 15 cancer patients at Bellevue Medical Center in New York City, the doctor conducting the research said that while it was difficult to make a definite evaluation, it was her opinion and that of her assistants that 14 of the patients showed no further growth of the cancerous tumors after spending a summer outdoors as much as possible, without wearing sunglasses or prescription lenses.
Subsequently, it was learned that the one patient whose condition detiorated at the expected rate did not understand the instructions and had continued to wear her prescription lenses when outdoors. The glasses naturally blocked the ultraviolet rays from reaching her eyes.
It appears that not only do we need sunlight on our skin to provide vitamin D from the ultraviolet rays, we also need invisible rays to reach our eyes, where the nerve fibers in the retina react to stimulate the master glands of the body. (Longwave blacklight ultraviolet rays are the beneficial ones; shortwave ultraviolet, which is filtered from natural sung light by the atmosphere before reaching us, is so harmful to living tissue that lamps which emit only those bands are used to sterilize implements. Shortwave ultraviolet is also the spectrum emitted from sunlamps, and it has been shown in animal tests that the over-exposure is harmful, possibly causing skin cancer.)
A prominent light researcher, John Ott, tells in his book, Health Light, of a conversation he had with the daughter of the late Dr. Albert Schweitzer:
” Our conversation dwelt mostly on her experiences as assistant to her father at Lambarene, on the west coast of Africa. I asked her about the rate of cancer of the people in that area, and she replied that when her father had first started the hospital, they found no cancer at all, but that now it was a problem. I asked if the people living there had started installing glass windows and electric lights in their otherwise simple surroundings and she said they had not.
“Then I half jokingly asked her if any of the natives wore sunglasses. She looked startled and then told me that the natives paddling their dugout canoes up and down the river in front of the hospital often wore no more than a loin cloth and sunglasses and indeed, some wore only the sunglasses. she further explained that sunglasses represented a status symbol of civilization and education and had a higher bartering blue than beads and other such trinkets. There is, of course, no scientific proof of a correlation between the wearing of sunglasses and cancer, but it does raise an interesting question.”
Bushs’ fault (couldn’t resist :-))
Does make one wonder. As a kid I spent way more time outdoors than indoors. Yet I am very nearsighted. My 3 three kids (now adults) have 20/20 vision and they didn't spend nearly as much time outdoors as I did when I was a kid.
Today’s kids don’t read as much as you did, when you were a kid.
Bushnell's Fault!
Well...THAT theory doesn’t explain my eyes....I’ve always READ, always...a lot....and no nearsightedness at all. I’m questioning whether it’s the “reading.”
Hmmm....so, do you think full spectrum lights help? My husband’s office is moving...to a space with NO WINDOWS!
No single activity will affect everybody the same way.
I don't buy it. I'm guessing most of us here can read this just fine:
I think you're right. I started reading at three, needed glasses at seven. Same story with my daughter. But I'd rather be smart than sighted! 8^)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.