
A movie changed one man's vision (2012) - Tomte
http://www.bbc.com/future/story/20120719-awoken-from-a-2d-world
======
naoru
Personal anecdote: I was born with astigmatism, hypermetropia with over 3
diopters difference between eyes, a slight esotropia, which was partially
corrected by training, and have developed amblyopia as the result of all that.

Naturally, I didn't even know about stereo vision, everything was flat and
that didn't bother me.

But when I was about 20 years old, my friend showed me Virtual Boy. After
looking into the headset I immediately sensed the depth and was blown away
with it.

Even after I took off the headset, depth perception didn't go away ever since.
It only became much stronger when I started wearing contact lenses.

Sorry for possible grammar mistakes, I haven't yet experienced anything like
Virtual Boy but for English, which is not my first language.

~~~
mrob
People advertise contact lenses as a fashion thing. "No ugly glasses." But the
biggest benefit of contact lenses is IMO "no pincushion/barrel distortion".
Especially if you need different correction for each eye, it can make a big
difference. I think a lot of people who wear glasses don't know you can avoid
the distortion with contact lenses.

~~~
tempguy9999
Glasses have saved my sight in an eye twice. Once was avoidable stupidity
(kids are dumb), once was unavoidable. I see them as protective as much as for
vision now. I don't want contacts.

~~~
pmoriarty
One other seriously negative thing about contacts is that unless you are
fastidious about cleaning or disposing them you risk eye infections, which
could potentially be very serious.

I used to wear disposable lenses, but out of lazyness and frugality, I'd leave
them in longer than I should have and suffered multiple eye infections.
Fortunately, no serious harm resulted from them, but I recognized the risk and
eventually switched back to wearing glasses. Since then I've never had to
worry about that stuff ever again.

~~~
UncleSlacky
I've used hard (gas-permeable) lenses for 35 years without problems, but then
I take them out every night and clean them. It's not nearly as difficult to
keep them clean as it is with soft/disposable ones.

~~~
Scipio_Afri
That is probably because you're using something like ClearCare which is a
buffered hydrogen peroxide (with some other stuff) and a case that acts as a
catalyst. The peroxide sterilizes your contacts, the catalyst slowly converts
all the hydrogen peroxide to water. It takes at least 6 hours and you have to
change the case out with every new bottle every month or so or else you get
hydrogen peroxide in your eyes, which even in small amounts is really awful. I
use to use the stuff by choice because it helped my eyes feel more comfortable
vs the other contact lens solutions (except for the days I was lazy and didn't
change out the cases or over wore my lenses past the X amount of days before
disposal). I had soft contacts, that's why it was a choice, but I'm pretty
sure hard contacts require the use of this type of cleaning method. Now I use
dailies because they're more comfortable even though they're crazy expensive.

------
smcameron
I've always been curious if stereoblind people are typically better at drawing
than people with normal stereo vision. I'm stereoblind, and I always seemed to
be better than most of my peers at drawing, and my hypothesis is that since
there are no stereo cues from a flat piece of paper (or rather, what stereo
cues there are are "wrong" if you're attempting to draw a 3D scene), the
stereoblind person is not going to be bothered by (nor attempt to
(incorrectly) render) discrepancies in stereo cues between what they're
drawing and what they're seeing.

~~~
munificent
My sister is a fantastic photographer. She has an incredible ability to look
at the entire 3D world around her and discover these little pieces of it that
make for an excellent two-dimensional image.

She is also famously clumsy, always tripping, dropping things, bumping into
stuff, aiming poorly, etc.

I've often wondered if poor stereo vision is the cause of both of those.

------
mrob
I have normal stereo vision, but I remember struggling for many hours to see
random dot autostereograms (e.g. Magic Eye images). And then suddenly I saw
the 3D image, and after that I never had trouble seeing them again. I've heard
many anecdotes of similar experiences. Maybe there's a similar kind of
learning in this case.

~~~
munificent
A large part of the struggle you experience with these is that you force your
eye to do two clashing operations that usually proceed in sync. Among the
signals our eyes use to detect depth are:

* Accommodation: Our lenses are flexible. We unconsciously contract the ciliary muscles in our eyes to change the shape of the lens so that it focuses light at different distances. It's very similar to adjusting the focus ring on a camera or binoculars.

* Convergence: As an object moves closer to you, in order for the object to stay centered on the fovea of each eye, your eyes need to turn inwards. To look at something really close, you go cross-eyed. When looking at something far away, your eyes are parallel.

Both of those involve muscular control that also give feedback to your brain.
So you can unconsciously feel how much your lenses are accommodating and your
eyeballs are converging. Typically, those signals are in sync with each other.

Autostereograms break that. To get the effect, you need to look "through" the
picture. When you do, each eye isn't actually centering the same part of the
picture on its fovea. That way, each eye gets a slightly different image, and
the differences between those two cause a parallax effect that we perceive as
depth.

The problem is that as far as accommodation is concerned, the picture is
close. The lenses really do need to focus on the picture itself to resolve a
sharp image. But for convergence, your eyes need to be closer to parallel as
if you were training your eyes on something past the picture.

Now your brain can tell these two things are out of sync and it gets very
confused. Some people seem to have an easier time decoupling these things than
others do. It ends up a feeling a little like patting your head and rubbing
your stomach at the same time.

------
crispsquirrel
"Like many of the 5-10% of the population living with stereoblindness"

What? 5-10% of those with stereoblindness or 5-10% of the general population
suffer with this?

~~~
lonelappde
5-10% of people are stereoblind

------
dang
Small thread from 2015:
[https://news.ycombinator.com/item?id=9993921](https://news.ycombinator.com/item?id=9993921)

------
aaron695
> Like many of the 5-10% of the population living with stereoblindness,

I would have called BS on this, but seems legit, just lacking a bit on nuance

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4934608/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4934608/)

"It is widely thought that about 5% of the population have a lazy eye and lack
stereo vision, so it is often supposed that most of the population (95%) have
good stereo abilities. We show that this is not the case; 68% have good to
excellent stereo (the haves) and 32% have moderate to poor stereo (the have-
nots). Why so many people lack good 3-D stereo vision is unclear but it is
likely to be neural and reversible."

