Children of a Thailand tribe who see with clarity beneath the waves (2016)
bbc.com
bbc.com
There is a trick that can help reduce eye irritation by salt, which may explain this : Eyes must be closed when crossing the interface between air and sea (that's usually instinctive) and also closed when crossing from sea to air (usually counter intuitive).
The reason is the protective tear film get broken upon crossing when eye is open.
You also need to avoid touching the corner of the eyes when your hands are covered of sea water. That usually the first reflex once the eyes are irritated, (if you must touch the corner of your eyes do so with your eyes closed). This trick is easier to learn, because when your eyes are not irritated and you touch the corner of your eyes with salty hands the irritation is instantaneous.
I recall my vision being far from perfect past 6 or 7 feet, but still pretty usable.
These days I need a low volume mask and contacts if I want to see anything in the water.
So I would think you can train your brain to process what you see underwater clearer with a lot of practice.
Just my amateur thoughts ....
I had a normal vision since I was born until I got an artificial lens in my right eye at 9 y.o. to deal with glaucoma caused by trauma. As you may guess, this new lens is not even close to the biological, as it has different elasticity and light refraction properties. The picture from my right eye is heavily abberrated, but my brain applies inverted abberation to the left eye's picture to have an almost perfect binocular vision. It wasn't like that on day 1 from operation, but progressed over a couple of years. Same thing with lens focus - it was 20/200 when I leaved the hospital, 20/30 after a year and 20/20 in two more, although the abberations couldn't be fixed.
I got the bright idea to have cataract surgery in my late 20's despite the cataract never really bothering me. While the sight in my left eye is now objectively "better", the surgery actually made my binocular vision worse because my brain isn't used to the new type and degree of aberration, and so doesn't yet know how to correct for it. I'm a few years out from the surgery and it's definitely better, but I kind of wish I'd left well enough alone.
I've tried to learn how to do this myself with very limited success. If I try to force my eyes to become blurry and then unblurry, I can notice some improvement in my ability to resolve images underwater. But this probably takes a lot of practice, and my lens is already starting to harden with age.
The brain does an awful lot with blurry and outright missing data. Look at something in your peripheral vision and name the colour of it, that's the brain filing in information that your eyes can't see. We only have good eyesight in a surprisingly small region directly in front of us.
> The dividing line between near and mid peripheral vision at 30° radius is based on several features of visual performance. Visual acuity declines by about 50% every 2.5° from the center up to 30°, at which point visual acuity declines more steeply.[18] Color perception is strong at 20° but weak at 40°.[19] 30° is thus taken as the dividing line between adequate and poor color perception. In dark-adapted vision, light sensitivity corresponds to rod density, which peaks just at 18°. From 18° towards the center, rod density declines rapidly. From 18° away from the center, rod density declines more gradually, in a curve with distinct inflection points resulting in two humps. The outer edge of the second hump is at about 30°, and corresponds to the outer edge of good night vision. - https://en.wikipedia.org/wiki/Peripheral_vision
So the weird thing is that both my eyes have a visual acuity around 20/120 or worse; that’s with correction (glasses) and it depends on the day (tiredness/dryness/etc) — but having lived this way my entire life essentially, I find it REALLY difficult to describe what it’s like to people. People think things off in the distance must be ‘blurry’, but that’s not the case at all. It’s more like ‘less detailed’, like if you turn the resolution and texture detail down. It’s not like an unfocused lens at all. There are studies I’ve found that seem to back this up.
Another problem I have that’s related is a nystagmus - both my eyes oscillate involuntarily from side-to-side, separate from the normal saccades (rapid eye movements) that everyone has. You’d think I’d see the whole world oscillating from side to side - but I don’t at all. I don’t usually even notice these movements when I look in the mirror, though I can see them if I’m looking at a video of my own face.
That is, most of the time. There’s one really strange failure mode I’ve observed - PWM-controlled small LED lights or segment displays like on a digital clock, particularly if they’re red but green as well, in a dark room. If it’s dim enough that I can still dimly see what surrounds the display, I can sometimes notice the LED oscillating left and right, WHILE THE STUFF SURROUNDING IT STAYS STILL. It’s really freaking weird!
in short: the eye and brain are complicated!
If I look at the car's rear trunk lid and hold my eyes still for a few seconds, the raised brake light starts moving up! (Or down, I don't remember which direction right now, but I think it's always the same direction.)
And it's not like everything in my vision is moving with it, that one raised light is moving all by itself. And it keeps moving and moving in the same direction, but somehow stays in the same place.
It's a strange experience, almost like a Shepard Tone of vision.
That went away over time, even as my prescription became much more nearsighted (I'm almost 9 diopters now)
I do have less near focus with corrective lenses.
If you hooked a camera up to a newborn’s ears and microphones to their eyes, the baby would learn to see imagery though their ears and hear sounds through their optic nerve.
The data quality would be horrible, but they’d still see and hear.
It’s the structure of the world (and our relationship to it) that creates meaning in our minds, not the structure of our brain. Although our brain is structured to get clearer signals through certain parts.
For many on HN, that's the way they are used to thinking of imagery, as a big array containing information about how strongly a grid of sensors was stimulated.
Here are some examples to try:
I have lost the ability to hear people in bars, or the 200sqft tile room where the elevators are at work, or when people are holding multiple conversations in a conference room.
I'm fortunate that I was able to identify the problem and prevent it from getting worse. It's amazing how just a small amount of missing information has effectively broken the "noise canceling and directional isolation" "software" of my brain.
Hearing loss isnt so much an inability to hear "quiet" (despite how hearing tests are performed) as it is a los of dynamic range. By wearing earplugs you can lower the volume of all conversations and prevent "clipping", so to speak.
Try it! Next time you're having trouble hearing someone try to plug your ears with your fingers.
When we'd be out and loud music was playing and somebody couldn't hear what he was saying to them, he'd lean in, speak more softly and place a finger lightly on the front part of their ear (so as to not put his finger in their ear).
He was always much easier to understand one he had done that, and we all picked up the habit. We weren't sure if the finger acted as a conductor, or what the explanation was, but reducing the dynamic range seems like a really good explanation.
They work, but it's annoying wearing them in all the time. I also have Sony XM3 adjusted to reduce most (not full) noise with anc and that helps quite a bit as well.
Like all experimental psychology from the 60's and probably today, you might want to see if it's been replicated.
https://en.wikipedia.org/wiki/Upside_down_goggles https://en.wikipedia.org/wiki/George_M._Stratton
Grew up near the ocean and swam almost every day.
Do you mean that you can see with total clarity? From back when I had good eyesight, I remember seeing blurry when opening my eyes underwater.
The kids had to dive underwater and place their heads onto a panel. From there they could see a card displaying either vertical or horizontal lines. Once they had stared at the card, they came back to the surface to report which direction the lines travelled. Each time they dived down, the lines would get thinner, making the task harder. It turned out that the Moken children were able to see twice as well as European children who performed the same experiment at a later date.
With the exception, I suppose, that with eye irritation it would be more difficult to complete the tests in the first place.
>She did notice, however, that the European kids would experience red eyes, irritated by the salt in the water, whereas the Moken children appeared to have no such problem. “So perhaps there is some adaptation there that allows them to dive down 30 times without any irritation,” she says.
http://pages.ucsd.edu/~jhaviland/Publications/ETHOSw.Diags.p...
Yes, I'm making an evolutionary guess.
You also have some populations who have been living in high altitude for many generations that have genetic adatptions to low-oxygen environments. https://www.sciencemag.org/news/2014/07/tibetans-inherited-h...
You'd imagine this would be basically a death sentence, but she's made it to old age. She also has a lack of adrenaline response, so is basically super chill. Hard to argue this is a beneficial mutation, but perhaps as technology evolves we could self-monitor artifically and not have to worry about these deeply unpleasant physiological warning bells?
http://discovermagazine.com/2012/jul-aug/06-humans-with-supe...
The title of the research paper is "Visual training improves underwater vision in children".