
Why might reading make people myopic? - amai
http://www.eye-tuebingen.de/the-institute/news-events/news/news-article/60-why-might-reading-make-myopic/
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tobr
Am I understanding this right? The choroid layer behind the retina gets
slightly thinner when we look at dark details on a bright background, and
slightly thicker when we look at bright details on a dark background, and
somehow this causes an opposite effect in the overall eye growth over time. So
spending a lot of time looking at dark letters on a bright background would
cause the eye to become too long and unable to focus on objects far away.

Is there an explanation for why the choroid changes its thickness, and why
this change would create an opposite effect in eye growth over a longer
period?

~~~
philipswood
So, they eye works pretty much like a camera - but it's not a camera: it's a
complex dynamic self-assembling, self-tuning adaptive structure.

The fact that it's geometry is roughly static around a focal length that has
sharp focus on the retina is a wonder of homeostasis with at least three known
tuning loops: 1) the lens Moving on swiftly... 2) a slower feedback loop
adjusting the choriod (hence focal length) in the order of hours. 3) an even
slower loop adjusting the eye geometry over longer periods of time.

~~~
philipswood
The story so far: We hack our visual sense to be a data channel for symbolic
information. This incidentally messes with the above homeostatic loops causing
myopia. We then hack the eye's optics to correct the immediately problem
without fixing the cause and oppose the corrective process by adding glasses
or contacts.

We end up at a myopic static point where the balance of forces match.

Big lens wins.

~~~
pen2l
This is just so wonderfully fascinating, that's all I have to say!

~~~
philipswood
Is fascinating - checkout
[https://www.sciencedirect.com/science/article/pii/S089662730...](https://www.sciencedirect.com/science/article/pii/S0896627304004933).
If you want to duckduckgo: Emmetropization

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nbeleski
I remember recently reading about the myopia increase in China and it was
largely attributed to children staying much more inside, out of the sunlight,
causing the eye to under-develop iirc.

I wonder how much these are correlated.

~~~
madeuptempacct
[https://www.npr.org/sections/goatsandsoda/2015/02/05/3837653...](https://www.npr.org/sections/goatsandsoda/2015/02/05/383765377/why-
is-nearsightedness-skyrocketing-among-chinese-youth)

There was a study that followed Chinese kids who stayed in China vs Chinese
kids who moved to Australia. There was a marked difference.

Not sure if its about sunlight or near/far focus though.

~~~
Apocryphon
They can test this if they tried getting students to try studying outside
under natural lighting for a while. Though in China that may be impractical
depending on the city.

~~~
lern_too_spel
They tested having students study in a sunlit classroom.
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536284/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536284/)

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gwbas1c
When I was a teenager I preferred white text on a black background. (Think of
the DOS terminal.)

In my very early 20s, I suddenly found white text on a black background
_extremely_ irritating. Suddenly, my vision was filled with persisting
horizontal lines. (Like what you get when you look quickly at a light bulb.)

Maybe it's because DOS was really grey on black, but on the web, people
typically do bright white on black?

~~~
VLM
Web era began around the rise of LCD displays. CRTs are too non-linear for
most people to tolerate black on white, so its a status symbol from around the
turn of the century to do white on black.

Not helping matters is the rise of glossy distraction screens, again before
the turn of the century the status symbol was ultra low glare matte screens to
avoid eyestrain and with the conversion to everything must be shiny its hard
to look at a black background reflecting tons of distracting moving shadows so
everything must have a white light blackground to cut thru the bright
distracting reflections.

~~~
crazygringo
> _CRTs are too non-linear for most people to tolerate black on white_

What does non-linear mean? And what do you mean tolerate?

Before LCD screens all Macs were black-on-white and people loved it. The first
Macs were monochrome. I don't recall anyone ever having a problem with it.

Also, I don't remember any matte CRTs -- they're _all_ glossy because their
surface is glass.

Really confused as to what you're talking about.

~~~
wingspar
Lot's of matte CRT's back in the day.. To name two: The 'flat screen' Zenith
CRT monitors.. Had a TV version that was awesome...
[https://www.chicagotribune.com/news/ct-
xpm-1987-05-13-870205...](https://www.chicagotribune.com/news/ct-
xpm-1987-05-13-8702050478-story.html)

Sony Trinitron
[https://en.wikipedia.org/wiki/Trinitron](https://en.wikipedia.org/wiki/Trinitron)

Mac's were color pre-LCD too.
[https://en.wikipedia.org/wiki/Apple_Macintosh_Color_Display](https://en.wikipedia.org/wiki/Apple_Macintosh_Color_Display)

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fhood
> However this is also necessary since we have about 125 Million pixel in the
> retina but only about 1 Million “cables” in the optic nerve.

Just switch to a busable protocol. I don't see what the issue is here.

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alexgmcm
"One would therefore expect that dark text on bright background would
stimulate myopia development and bright text on dark background would inhibit
myopia."

Another reason to use dark themes.

~~~
Santosh83
But how to invert the colour of web pages? Dark themes darken the UI but the
webpage is almost always still dark text on light background.

~~~
kbutler
There are lots of addons available - here is a highly rated one:
[https://darkreader.org/](https://darkreader.org/)

~~~
sdfin
Thanks for sharing, that addon works marvelously. I tried similar ones before
but they made various pages unreadable. This one gets most pages right.

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arendtio
Thank god, terminals have dark backgrounds by default :D

~~~
4ad
What default is that?

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theriddlr
Could be CRT vs. LCDs. Family all have bad eyesight but my younger sister who
spends every waking hour gaming doesn't need glasses. I spent less time on the
computer when I was her age but I had a CRT monitor.

~~~
madeuptempacct
I am a 99% sure that "some people are just immune." I have friends my age who
played games way more with perfect eyes. I also have a friend who drank soda
at work all day and never had a single cavity.

~~~
doombolt
We should take their genes responsible for that, put it in our future embryos.

Essentially turning "genetic lottery" into "genetic basic income".

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DrNuke
There are a few gym protocols used to train / flex / exert the eyes’ muscles
and revert myopia gradually. An expert tutor acting under your doc’s
supervision is needed, though.

~~~
elektor
What you're describing is the Bates Model, which has not been objectively
shown to improve eyesight.

~~~
DrNuke
Nah, there are more recent studies based upon first principles and less
stretching protocols than Bates. Still not accepted best practice, though, so
individual mileage may vary, my myopic eyesight improved enough to give them a
pass.

~~~
Deinos
Could you share these sources please? Interested in seeing how newer models
improve upon The Bates Method.

~~~
DrNuke
Sure, some fundamentals are here and absolutely no money is needed to
understand the principles better: [https://gettingstronger.org/2016/03/faq-
for-vision-improveme...](https://gettingstronger.org/2016/03/faq-for-vision-
improvement-by-hormetism/) .

~~~
testvox
That page neither contains or links to any actual data on the effectiveness of
any of the techniques described.

~~~
DrNuke
Nor I claimed they do, though, as for my previous, very clear comments about
this matter above.

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alexgmcm
Also I wonder if this means TV and Video Games etc. aren't as bad for eyesight
as they should have the same visual statistics as natural scenes (as they
display natural scenes more or less) despite TV being demonised as bad for
eyesight for generations.

Whereas when you think about it staring at dark symbols on a bright background
is really unnatural and therefore it is reasonable that it can affect visual
development.

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01100011
So does this mean that my preferred color scheme of light text on a dark
background might be accelerating my presbyopia? I'm at the perfect age for it
to start(43), but it sure seems to be progressing fast.

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k__
I'd say "well that explains everything" after I spent most of my time before a
monitor since I was ten.

But I'm not myopic, but astigmatic.

~~~
walterbell
How is your neck posture? Reading sideways in bed can also affect visual
cortex.

~~~
k__
Never did that. Felt rather tyring quick

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matt-snider
As a German speaker, this title seems very Denglish-ey to me. Is this phrasing
valid in English? It seems like the object of 'to make' is necessary and
missing, whereas in German it is perfectly normal and correct to phrase things
this way (e.g. Tofu macht satt, or Schnaps macht betrunken, whereas in English
you'd say: tofu makes __you __full /is filling, or shnaps makes/gets __you
__drunk).

Not trying to nitpick, just curious if this is actually correct grammar or
not.

~~~
jackpirate
As a native English speaker, you're correct.

~~~
stephenhuey
I’m also a native speaker, and I find this construction recognizable from some
literature. Just searched for examples of whether a grammar teacher would
allow transitive verbs without direct objects, and I found one of the answers
here suggesting it’s ok in English because the object can be inferred from
context:

[https://ell.stackexchange.com/questions/43482/a-transitive-v...](https://ell.stackexchange.com/questions/43482/a-transitive-
verb-without-a-direct-object)

