Seeing the Light: Why Sun Exposure May Be Good for Your Eyes
Marks Daily Apple
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myself in all things Primal for so long, I find myself viewing nearly
everything through the prism of human evolution. Is this food, activity,
environmental stimulus, or social more an evolutionary novelty?
If so, might it possibly conflict with or impede our pursuit of
good health? Is it benign? An improvement, even?
logic will only get you so far. It'll give you a nudge in the
right direction that is, headed straight to honest inquiry and
further research but it's not enough. You shouldn't rest on your
laurels if Grok logic suggests what you're doing is right, and you
shouldn't make big changes just because Grok logic suggests you're
doing something wrong. Instead, use those insights to generate hypotheses,
then try to explore them. Research, read, ask more questions. At
least, that's what I try to do. It's awfully tempting to just go
with conjecture (especially if it turns out to be right on a fairly
preamble was just my way of setting up yet another question with
roots in evolutionary conjecture: does the avoidance of
sunlight via indoor living, sunglasses, and general heliophobia
have an impact on eyesight, and more specifically nearsightnedness?
Going purely by Grok logic and what we know about sunlight's interaction
with other aspects of our health, I think it's a reasonable question.
and skin Sunlight exposure is required for vitamin
D synthesis. When UVB hits our exposed skin, vitamin D is synthesized
and distributed throughout our body. Vitamin D is an essential pro-hormone,
necessary for musculoskeletal health, immune system robustness,
as well as protection from heart disease and cancer.
and circadian rhythm We need exposure to light at certain
times of the day in order to regulate our circadian
rhythms. Without daytime/morning light, or with too much evening
light, our internal clocks and general health go awry.
two extremely basic, widely-accepted interactions between sunlight
and our bodies, coupled with the fact that the eye's express function
is to interact directly with light, I think Grok logic regarding
the sun and our eye health might be onto something. But we can't
be sure, remember, without confirming through other sources.
So let's look
into those other sources.
I'm sure you've
heard of myopia. You may have it yourself or know someone who does.
In case you don't, myopia is nearsightedness, which is characterized
by blurry vision when looking at distant objects. If it weren't
so easily countered with prescription eyeglasses, myopia would probably
be classified as a public health epidemic. It's that common, and
it's getting worse.
In fact, the
indicate that 41.6% of Americans aged 12-54 suffer from myopia,
way up from 25% in the early 1970s. That's an awfully big percentage
of the tribe that can't throw a spear, shoot an arrow, spot prey,
or see the enemy coming from afar. That's a ton of squinters who
require assistance. In other words, if myopia were just
an unfortunate part of growing old (to the ripe old age of 12!),
we probably wouldn't have made it this long.
probably an environmental component to the rise of myopia. Genetics
could play a part in determining susceptibility to myopia, and probably
do, but an environmental factor is likely to be a trigger for
the "myopia gene's" expression. Could sunlight be just such an environmental
a visual disorder researcher, thinks
so. First, she points to the weak or inconsistent epidemiology
that attempts to link time spent on the computer, watching television,
reading, and studying to the development of myopia, instead suggesting
that the real problem is lack of sunlight. In cases where
digital media usage or inside work appears to be associated with
myopia, Rose thinks it's actually a measure of displaced outdoor
the rest of the article
June 29, 2011
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