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Author Topic:   Do glasses lead to bad eyesight evolving?
Blue Jay
Member (Idle past 2698 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 16 of 25 (574204)
08-14-2010 4:18 PM
Reply to: Message 13 by jar
08-14-2010 11:51 AM


Re: good points, but...
Hi, Jar.
jar writes:
In addition, in a cooperative society many eyesight defects can also be an advantage. Those who are near sighted may well be better at detailed tasks that require close vision. Others who are far sighted may be better as lookouts and perhaps hunters.
And, since many girls like nerds, and glasses are a symbol of nerdiness, glasses may also confer a reproductive advantage, thereby providing an avenue through which changes in the quality of eyesight may translate into evolution.

-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.

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Buzsaw
Inactive Member


Message 17 of 25 (574205)
08-14-2010 4:27 PM
Reply to: Message 15 by Percy
08-14-2010 3:19 PM


Re: Not sure I agree
Percy writes:
If I understood you properly, then your experience is very atypical. Most people become more farsighted with age. As we age nearly unavoidable physiological changes occur in the eye that cause longer and longer focal lengths.
Hi Percy. At 75 then, I'm also atypical, having never in my life worn glasses. Though I am out and about a lot, I find it needful to squint some for distant focus and correcting double vision. However, I can still read very fine print clearly. The more time I spend reading or on the computer, the more I squint for distance.
I have always regarded eye glasses like crutches. By refusing to wear glasses my eyes microevolutionize (buzism ) into focus. Previous to about 35 years ago my right eye was my good eye. Due to a misshap, my right eye became somewhat blurry and I had to squint for focus closeup. It wasn't long before usage of my blurry left eye corrected it, causing it to become my good eye, my right eye being somewhat blurry.
I've said the above to say that glasses lead to bad eyesight micro-evolving, i.e. eyesight deterioration.
For what it's worth, I eat and treat the body wholistically, for health.

BUZSAW B 4 U 2 C Y BUZ SAW.
The immeasurable present eternally extends the infinite past and infinitely consumes the eternal future.

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nwr
Member
Posts: 6408
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.1


Message 18 of 25 (574212)
08-14-2010 5:54 PM
Reply to: Message 15 by Percy
08-14-2010 3:19 PM


Re: Not sure I agree
Percy writes:
If I understood you properly, then your experience is very atypical. Most people become more farsighted with age.
I don't think that's the full story.
In the population at large, far sightedness is more common than near sightedness. In academia, nearsightedness appears to be more common.

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 Message 19 by Theodoric, posted 08-14-2010 6:21 PM nwr has replied
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Theodoric
Member
Posts: 9076
From: Northwest, WI, USA
Joined: 08-15-2005
Member Rating: 3.7


Message 19 of 25 (574215)
08-14-2010 6:21 PM
Reply to: Message 18 by nwr
08-14-2010 5:54 PM


Re: Not sure I agree
Not that I don't trust you, but do you have any references for this?

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nwr
Member
Posts: 6408
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.1


Message 20 of 25 (574219)
08-14-2010 8:00 PM
Reply to: Message 19 by Theodoric
08-14-2010 6:21 PM


Re: Not sure I agree
I tried using google to look for some references. Unfortunately, "myopia" seems to be often used in a metaphorical sense, and a search on "myopia academia" mainly turned up such references. It did turn up a few hints:
Link between myopia and intelligence
... the 66.4 percent increase in myopia in Americans since the 1970s, ...
a curious youtube video
It turned out that the wikipedia entry on myopia has a lot of information. As you read that entry, there are a number of comments on the association between myopia and doing a lot of near work. At present there are only ambiguous conclusions, so this is as yet not adequately explained.

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Theodoric
Member
Posts: 9076
From: Northwest, WI, USA
Joined: 08-15-2005
Member Rating: 3.7


Message 21 of 25 (574220)
08-14-2010 8:10 PM
Reply to: Message 20 by nwr
08-14-2010 8:00 PM


Re: Not sure I agree
So basically you have nothing to back this?
In the population at large, far sightedness is more common than near sightedness. In academia, nearsightedness appears to be more common.
Edited by Theodoric, : Punctuation

Facts don't lie or have an agenda. Facts are just facts

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nwr
Member
Posts: 6408
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.1


Message 22 of 25 (574223)
08-14-2010 8:44 PM
Reply to: Message 21 by Theodoric
08-14-2010 8:10 PM


Re: Not sure I agree
My comment was based on personal observation, and on what my eye doctors have said (presumably based on their own anecdotal experience).
I have added some more links, which also seem to indicate the same association. The last one, showing a relation with time spent outdoors, is perhaps the closest to being on the right track. But this needs more research.
Accommodation and Near Work
Comparisons between myopia rates in 1882 and 1964 showed that the rate is very different for individual professions68 (students in the 30% range, unskilled workers in the 2 to 3% range): While the total rate of myopia was increasing, the myopia rate for all the individual professions except unskilled work was decreasing. Explanation: The overall increase in myopia, according to these results, can be largely attributed to a changed ratio of job distributions from unskilled work towards professional and office work.
Highly elevated rates of myopia were found for craftspeople of various professions, who have to do extensive near work, e.g. for typesetters (in year 1930117), tailoring (in the years 1953118 and 1961119). Up to 77% of the persons in these professions were found to be myopic.
Role of Near Work in Myopia: Findings in a Sample of Australian School Children
Because of the association of myopia with educational performance and close-work occupations, near work has long been considered an environmental risk factor for the development of myopia. Among the various pillars of supporting evidence that link myopia to education and near work are the higher myopia prevalence rates that paralleled the introduction of schooling in Eskimo populations, the higher prevalence of myopia in orthodox Jewish boys who undertook intense schooling compared with that in orthodox girls or boys and girls in general schools, and the presence of myopia among Chinese fishermen who reported reading in childhood.
An NPR report
"If you have two nearsighted parents and you engage in a low level of outdoor activity, your chances of becoming myopic by the eighth grade are about 60 percent," he says. "If children engaged in over 14 hours per week of outdoor activity, their chances of becoming nearsighted were now only about 20 percent. So it was quite a dramatic reduction in the risk of becoming myopic."
At first, that seems to support the theory that near-work causes nearsightedness: The more time kids spend indoors, the more likely they're watching TV or reading a book.
But then Mutti and his colleagues looked closely at the kids before they became nearsighted. And the reading and close-up things they did didn't predict who'd be nearsighted later. "What we found is that near-work had no influence at all," he says. "Children really aren't doing any more or less near-work the children who are becoming nearsighted."
So that's another mystery. Why, then, does spending time outdoors make a difference? At first, scientists thought the outdoor exercise was the key. But it turned out kids who get indoor exercise don't get the benefits of reduced myopia.
Now, researchers are studying whether outdoor light somehow changes the way the eye grows.

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Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.3


Message 23 of 25 (574225)
08-14-2010 9:29 PM
Reply to: Message 18 by nwr
08-14-2010 5:54 PM


Re: Not sure I agree
nwr writes:
In the population at large, far sightedness is more common than near sightedness. In academia, nearsightedness appears to be more common.
The physiological changes in the eye that most often occur with age are independent of where one begins on the near/far sighted scale. The eye tends to elongate front to back, and the lens tends to grow away from the ring of muscle that surrounds it. There's no guarantee this will happen, but it's what happens to most people as they age.
For most people, sometime between age 40 and age 60 their eyes take on a fixed focal length. For people nearsighted in youth they often discover their eyesight improves with age. Those lucky enough to have their focal length freeze up at some useful distance such as 8 or 10 feet might find that they see well enough at both near and far distances to not need glasses most of the time.
--Percy

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bluescat48
Member (Idle past 4190 days)
Posts: 2347
From: United States
Joined: 10-06-2007


Message 24 of 25 (574254)
08-14-2010 11:37 PM
Reply to: Message 23 by Percy
08-14-2010 9:29 PM


Re: Not sure I agree
For most people, sometime between age 40 and age 60 their eyes take on a fixed focal length. For people nearsighted in youth they often discover their eyesight improves with age. Those lucky enough to have their focal length freeze up at some useful distance such as 8 or 10 feet might find that they see well enough at both near and far distances to not need glasses most of the time.
That fits me to a "T" When I was a teenager my vision was 20/200 in the left eye & 20/400 in the right one. At 35 my vision had already stated going the other way 20/100 & 20/200 by 45 it was 20/20 in the left and 20/40 in the right. At age 55 I no longer needed glasses for distance just reading glasses. Which has not ckanged in the last seven years.
Edited by bluescat48, : added line
Edited by bluescat48, : 3 where 2 should have been my typpiccalk tpign

There is no better love between 2 people than mutual respect for each other WT Young, 2002
Who gave anyone the authority to call me an authority on anything. WT Young, 1969
Since Evolution is only ~90% correct it should be thrown out and replaced by Creation which has even a lower % of correctness. W T Young, 2008

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Jeff Davis
Junior Member (Idle past 4919 days)
Posts: 29
Joined: 09-05-2010


Message 25 of 25 (582594)
09-22-2010 9:17 AM
Reply to: Message 24 by bluescat48
08-14-2010 11:37 PM


Re: Not sure I agree
Hi,
Some of my points overlap others, but here goes...
Recent observed changes in a particular human population within the last few hundred years is not the same thing a evolution (i.e., a change in the frequency of alleles through successive generations), such as changes in eye sight or even taller human beings today than the Middle Ages. Environmental factors are affecting these, such as a higher percentage of people reading or a change in diet.
Some have made comments about earlier generations indeed having eyesight problems, and I'm sure this was the case during hunter-gatherer times. In a hunter-gatherer society, the oldest individuals (those most likely having the worst eyesight) most likely have changed their group contribution to activities not requiring acute eyesight. Also, when you watch today's hunter-gatherers hunt, they hunt in groups. I can easily see the older experienced hunters in charge and evaluating tracks, while the younger "well-sighted" individuals learning this skill but also doing their part by identifying prey at great distances. Not everyone needs to have keen eyesight in order to have an affective hunting team.
Great thread.
best,
Edited by Jeff Davis, : No reason given.

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