
Children who see clearly underwater - oska
http://www.bbc.com/future/story/20160229-the-sea-nomad-children-who-see-like-dolphins
======
Pyxl101
Did you know that your eyes can adapt to being open in sea water? When you
first open them underwater in the sea, they'll sting like crazy. If you
persist - or at least this was the case for me, that effect will go away, and
you can open them underwater without pain.

They will still be unfocused, though, of course. From the article, it sounds
like you need to practice for a while before the eye learns how to focus
underwater:

> Gislen wondered whether the Moken children had a genetic anomaly to thank
> for their ability to see underwater or whether it was just down to practice.
> To find out, she asked a group of European children on holiday in Thailand,
> and a group of children in Sweden to take part in training sessions, in
> which they dived underwater and tried to work out the direction of lines on
> a card. After 11 sessions across one month, both groups had attained the
> same underwater acuity as the Moken children.

Perhaps this only works for children, who seem somehow more biologically
adaptable? The body is quite adaptable in general so I would believe it that
people who swim regularly could see better underwater. I'm glad to have the
science though to study the effect more rigorously.

~~~
pcl
_Did you know that your eyes can adapt to being open in sea water?_

Wow... I didn't know that. Losing my mask and panicking while diving has
always been a concern of mine. I'll have to try this out. Regardless of being
able to see clearly, it'd be great to just not be bothered by an onslaught of
seawater.

~~~
iamphilrae
Your tears are very salty so seawater actually isnt that different from the
water that's already in your eyes. A lot of panic people have in opening their
eyes in seawater stems from their experience of chlorinated swimming pools -
which absolutely stings like hell!

~~~
narag
I don't know why, but seawater in my eyes absolutely causes me _pain_ , not
_panic_.

~~~
pcl
Yep. But when something goes wrong and you're 80 feet underwater, panic is not
far away, and is really risky, since the panic response is unlikely to be the
safe thing to do when deep underwater. So anything I can do to become
acclimatized to problems is a win.

------
eggy
My last job for 6 years was fixing hydraulics and electrical systems under
water, among other things. I am now 51, and at that time, my presbyopia, or
farsightedness increased. I wear +1.50 reading glasses topside. Just old age,
and the len's inability to accommodate as much as when you are younger. I
could open my eyes, maskless in fresh or salt water. And it is not chlorine
that burns your eyes in most cases. If you think you smell chlorine, you're
mistaken; chlorine is odorless. It is the byproducts of free chlorine that eat
abundant organic matter that creates chloramines that you are smelling. A sure
indicator they did not maintain a minimum level of free chlorine to begin
with. In any case, I was able to improve my work underwater over those six
years. If you discount feeling with my hands, what augmented my ability was
not pupil dilation or lens accommodation, but the brain's processing. It has
been proven if you concentrate while reading without your reading glasses, you
can train your years of reading to recognize the letter shapes in their new
blurry appearance. Not magic here, hard work. What I would be interested in is
did she change it from merely horizontal and vertical lines? I can easily see
the brain also augmenting their ability to accommodate their lens and pupil
dilation to make their ability even more impressive. This would explain how
the European children may have 'thought' they saw clearer, but it was the
brain clarifying their perception and not any lens or pupil dilation in their
short study.

~~~
david-given
I remember hearing from someone who was on a long cruise trip, and on their
first day, lost their glasses without hope for replacement. So they just had
to cope with the rest of the trip without.

They said that it took a while to learn to cope, but once they did their
short-sightedness didn't affect everyday life at all, apart from not being
able to read. This included things like playing tennis.

I'm -4.5 in both eyes, and, interestingly, if I take my glasses off I can just
about make out the words I'm typing here without adjusting the zoom level;
mostly from shape. Zooming in a couple of notches makes the letters appear.
Blurry and distorted, but legible (just). I can totally believe that practice
would make me reasonably functional.

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Grazester
This is interesting. I am from the Caribbean and my parents a small
rock(basically) off the coast of the mainland where your lively hood depended
on the sea in one way or the other(fishing, diving, boat building). As a kid I
would spend a lot of time in the water there swimming and diving. I felt like
my underwater vision was so much better. This might not have been just a
feeling then.

~~~
YeGoblynQueenne
I've spent a lot of time in the see also but I always had blurry vision
underwater. I've always preferred to use a mask when I could.

Maybe it's just something you need to be aware of culturally, to even attempt
it?

~~~
speeder
I am a urban person that could see underwater, and until now I wasn't aware
that it was something that could be learned, I just love diving in pools, and
could not afford any equipment, so I got used to diving with eyes open, even
in stupid high chlorine pools, and I don't need to mechanically close my
nostrils either.

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chrisb
This links to something that's occasionally interested me.

Are you able to consciously refocus your eye?

By this I mean stare at an object (with one eye), and consciously make it go
in and out of focus, whilst always staring straight at it.

I find that I can do this to a certain extent - is this something that most
people can do?

~~~
Coding_Cat
There are hidden picture books which look like random noise until you manage
to focus your eyes 'behind' the book. I could never do that but others could.
So I would say yes, you can with some effort.

~~~
chrisb
Are you talking about "Magic Eye" pictures like this:
[http://mentalfloss.com/article/29771/why-cant-some-people-
se...](http://mentalfloss.com/article/29771/why-cant-some-people-see-magic-
eye-pictures) ?

If so, this isn't really what I mean.

I mean with just one eye, being able to consciously refocus that eye. For
example, looking at this writing on your screen able to make that go in and
out of focus.

~~~
Coding_Cat
I can do that, focusing outward is easier than inward though. Unless I hold a
finger in between the screen and my eye, then it's the opposite.

~~~
chenglou
Can you elaborate on the finger trick? I can still only focus outward (aka
blurring, if that's what you mean)

~~~
Coding_Cat
I can bring my finger into focus, drawing my focal point in front of the
screen, and if then remove my finger I can hold that focus (with about a 50%
success rate). Perhaps that is cheating a little ;).

------
Coding_Cat
Huh, I didn't know this was something special. I used to swim underwater with
my eyes open all the time when I was little and I could see underwater just
fine like the article describes. I just assumed everyone could :).

Although I couldn't do it in salt water, it stung my eyes too much but that
might also be due to me learning to swim in pools instead of the sea.

~~~
awqrre
They are talking about sea water...

~~~
mattdeboard
Hm. Salt water is (according to my google-fu) denser than fresh water. The
article says, "When the eye is immersed in water, which has about the same
density as the cornea, we lose the refractive power of the cornea..."

I wonder if this refers to salt or fresh water. Maybe both, if the density
delta between the two is trivial.

------
mirimir
When I was young, as I recall, I could see better underwater than normally.
I'm _very_ nearsighted.

~~~
mikekchar
I had the same experience. It's strange. I always thought that was normal
(that you could see better underwater than above water). I don't really like
swimming, so I haven't done it more than once or twice as an adult. Now I'm
curious if I would have the same experience.

~~~
mirimir
Maybe swimming a lot underwater causes nearsightedness. But then, in the
article, I see:

> She thought the first theory was unlikely, because a fundamental change to
> the eye would probably mean the kids wouldn’t be able to see well above
> water. A simple eye test proved this to be true – the Moken children could
> see just as well above water as European children of a similar age.

------
eugenekolo2
Is their vision better than using goggles?

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blubb-fish
Could the BBC please stop promoting their stuff here? Thanks!

~~~
DanBC
The submitter has posted 2 links to the BBC in their last 30 submissions.

The last 30 submissions of bbc.com were submitted by about 25 different
accounts.

Why do you think this article doesn't belong here?

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PhantomGremlin
Maybe I'm just a wuss, but the only thing I could think of is why would
someone want to open their eyes underwater? E.g. a quick google turned up:

    
    
       a liter of seawater collected in marine surface
       waters typically contains at least 10 billion
       microbes and 100 billion viruses[1]
    

No, thank you.

[1] [http://www.the-
scientist.com/?articles.view/articleNo/36120/...](http://www.the-
scientist.com/?articles.view/articleNo/36120/title/An-Ocean-of-Viruses/)

~~~
mattdeboard
Fishing, i.e. food & money.

~~~
PhantomGremlin
Yes, of course, the people in Thailand do it to survive.

I was thinking more along the lines of first-world people, especially
children. E.g. exposing "European children on holiday in Thailand" to what I
stereotype as the fetid waters off the coast of third world countries.

It may be a stereotype, but that doesn't mean it's not true. I'd venture that
the phrase "sewage treatment plant" is not part of the vernacular there.

~~~
eru
> E.g. exposing "European children on holiday in Thailand" to what I
> stereotype as the fetid waters off the coast of third world countries.

Thailand ain't exactly third world. (The waters can be dirty, though.)

