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The myopia boom (2015)

nature.com

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Re: The myopia boom (2015)

#51

Post by dingleberry »

hetman wrote: post #47
dingleberry wrote: post #41

light intensity does that try this: take a picture, same object, no flash, ... one under normal bright sun and another in a room under normal bright lighting. which one is sharper? set phone brightness to lowest, another on highest. try to read something and measure your arm's length. adjust brightness so you can still focus at farthest arm's length as comfort dictates. don't save on power juice. your eyes are more i…

More specifically it's the bright light triggering the iris to close that improves the focus. As the aperture narrows (iris closes) the incoming rays become more collimated (less scattered) and so the image falling on your cornea appears sharper even if your eye's lens is not able to focus it correctly. At it's extreme this effect allows the pinhole camera to work without using any lenses at all to focus the image. T…

not really...

seeing things under sun is not equal to squirting ur eyes to focus the incoming rays

it's just that much light coming, the intensity of light to be exact.

that's why camera, given the same setup, gives sharper image under bright sun light

I never get as tired playing outside as compared to squirting my eyes all the time just to focus in a room. sun light is just that intense, rooms lightings are much less intense.

Re: The myopia boom (2015)

#53

Post by [deleted] »

jeffdavis wrote: post #46
jacobwilliamroy wrote: post #27

I always thought it was because all of the "far away" stuff is outside and a person who spends 90% of their time indoors never has to look at anything far away. What are the rates of shortsightedness among people living in dense forests (or some other cramped outdoor environment)?

How would you study those two potential variables seperately to find the true cause? It would be difficult to have such a large indoor area that people regularly focus far away. But maybe you could keep UV lights on indoors in an animal study to see if the UV light reduces myopia.

[deleted]

Re: The myopia boom (2015)

#54

Post by inciampati »

graeme wrote: post #45
joezydeco wrote: post #33

Earlier quoted context omitted.

The evidence is firming up that UV (esp UV-B) exposure is linked to cataracts and macular degeneration. https://nei.nih.gov/news/briefs/uv_cataract https://www.macular.org/ultra-violet-and-blue-light Blue light from LEDs that are out of spec can also be a problem. The EU already has standards for this. http://www.cree.com/led-components/media/documents/XLamp_Eye...

Are those "blue light wakeup devices" a risk for this?

Given their intensity they very well could be. I actually stopped using one after a few months due to this concern.

Re: The myopia boom (2015)

#56

Post by dingo_bat »

jacobwilliamroy wrote: post #27

I always thought it was because all of the "far away" stuff is outside and a person who spends 90% of their time indoors never has to look at anything far away. What are the rates of shortsightedness among people living in dense forests (or some other cramped outdoor environment)?

Nearsightedness seldom means you can see all nearby stuff. For me, even a notebook kept on my desk is too "far". I don't think living in a dense forest would change anything. I don't think growing nearsightedness is because we are "evolving" to our surroundings.

Re: The myopia boom (2015)

#58

Post by throwaway84742 »

20after4 wrote: post #55
dd36 wrote: post #48

Earlier quoted context omitted.

Filtered cows blood causes growth?

No. Growth hormone given to cows which winds up in the milk.

Cow growth hormone does not work on humans. And even if it did, it gets destroyed by acid in the stomach. That’s why bodybuilders inject HGH instead of taking it orally.

Re: The myopia boom (2015)

#59

Post by whiskyant »

jacobwilliamroy wrote: post #27

I always thought it was because all of the "far away" stuff is outside and a person who spends 90% of their time indoors never has to look at anything far away. What are the rates of shortsightedness among people living in dense forests (or some other cramped outdoor environment)?

I think the eye damage is more to do with looking at something of fixed distance for long periods of time (computers, tvs, tablets, & phones).

A person living in a dense forest would still be constantly adjusting his/her focus.

Re: The myopia boom (2015)

#60

Post by tomxor »

tomxor wrote: post #43
koverda wrote: post #4

What if we make cellphone screens which emit 10,000 lux? Boom. Problem solved.

I know you are being facetious but it's probably important to note that the LED and oLED light used in phones is not wide spectrum. I think attempting to generate the equivalent intensity of natural light means unnaturally high intensity three component narrow band frequency exposure?... I can imagine that might pose a non obvious risk to eyes because it _looks_ visibly equivalent. (sorry I am unable to reference it…

Found it: https://news.ycombinator.com/item?id=12575725

Note: the top rated post has focused on editorial quality and glossed over the fact that it is narrow band light and cannot be compared as equivalently in wide spectrum terms beyond perception (e.g colour temperature), this is pointed out in the 2nd immediate child by sandworm101.

I should point out that the properties of the light beyond perception _are_ important due to ipRGCs: the mammalian retina contains ipRGC photo-receptors that do not relay images to the brain but are responsible for various reflexive responses. These receptors are sensitive to a wide spectrum of light peeking around blue [1]. Ultimately these ipRGCs release melanopsin which is known to affect circadian rhythm, and is thought to control sleep wake patterns [2].

I expect you've heard about this vaugley before as I have, but what is interesting in the context of LEDs is that ipRGCs appear to respond to more of a continuum of spectrum, so unlike our cones they would be "perceiving" LED light quite differently to our consciously perceived images.

[1] https://en.wikipedia.org/wiki/Melanopsin#Function

[2] https://en.wikipedia.org/wiki/Melanopsin#Control_of_sleep/wa...

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