

3D Video Hazardous to Your Health - hernan7
http://www.audioholics.com/news/editorials/warning-3d-video-hazardous-to-your-health/

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barrkel
First up, strabismus implies you're primarily using your dominant eye, and
ignoring input from the other eye. In this state, 3D vision based on different
inputs to each eye won't do anything for you. If you weren't solid on eye gaze
coordination for 3D perception before viewing 3D video, I can maybe buy that
it increases the risk that you don't settle in properly. But if you do have
eye gaze coordination already, I would believe that 3D vision you can easily
track - i.e. alter your gaze point appropriately to coordinate images from
both eyes - would not impair this skill, and may even improve it.

I played around with stereograms a bunch when I was 12 or so. I got to making
my own using graph paper, creating a random dot pattern, and then carefully
repeating it with adjustments to generate the desired depth cues when viewed
with crossed vision - the near approach - or parallel vision, the far
approach.

So, I did this for many, many hours over a period of weeks. The most practical
upshot - if you can call it practical - is that I'm now extremely good at
"spot the difference" puzzles, as I can change the intersection point of my
eye gaze at will, even to the point of infinity (parallel gaze) and slightly
beyond (so that my eyes are actually looking outward in slightly different
directions). The practice of conscious control also decouples corneal focusing
from gaze direction as desired.

Another slight plus is that I find it reasonably easy to relax my eyes,
putting on a "1000 yard stare", including distance-focusing my eyes. I often
do this when I'm sitting by the computer, but caught up in thought. FWIW, I'm
slightly short-sighted, but have experienced no loss in visual acuity in 20
years of almost entirely indoor, close computer work.

I feel pretty confident from my personal experience in saying that I'm not
afraid that there will be any side-effects from 3D video. But I am only an
anecdote, and I don't own a television, much less would I consider buying a 3D
TV.

~~~
cj
Your ability to control your focusing was something you learned how to do
_after_ your visual pathways were fully developed. For you, your stereograms
didn't interfere with your initial development.

As the article says, 3D in moderation for adults is fine. The article is
mostly concerned about the development of children's visual pathways during
their critical periods.

~~~
barrkel
If you read what I wrote, you'll see that I said that once you're _already_
solid on gaze coordination, then I think 3D video _that you could easily
track_ wouldn't do harm. Those are caveats, and are probably related not just
to age, but individual capabilities (as I said I'm _just an anecdote_ ).

Secondly, if you read the article, you'll see that it's titled "3D video
hazardous to _your_ health", not "3D video hazardous to _your kids'_ health".
The article also conjectures that "one can surmise that it’s also never too
late to learn bad habits that could create visual problems". So, if you read
the article carefully, you'll see that it is _not_ mostly concerned with the
development of children's visual pathways, but rather is interested in
promoting fear for adults too.

------
codeflo
The argument is that because watching 3D movies forces your eyes to focus in a
different way (which is true), you'll forget how to properly focus objects in
the real world. I think that's a bit sensationalist, and akin to the argument
in the 1800s that the enormous speed of railways is hazardous to your health.

It's not even like 3D images are a completely new invention. The article even
mentions stereograms, which have been around for many years, force your eyes
into a position that's even more extreme, and have been really popular at one
point. I don't remember a widespread outbreak of lazy eye because of those
pictures.

~~~
gojomo
Looking at stereograms is seconds at a time. Movies, TV and video games are
hours at a time.

There are reasons previous attempts to mass-market polarized stereo 3D -- a
technology over 50 years old -- keep petering out after short periods of
enthusiasm.

As evidenced from the SRI/Sega experience, this demonstrable lingering effect
on stereo vision is a major factor.

~~~
barrkel
What you have there is two separate things: the SRI/Sega tests which indicated
possible harm to children from 3D headsets, along with product failure of 3D.
But I don't think you can draw a causal factor from one to the other, that 3D
headsets were a product failure because of harm to children, without
introducing more evidence.

There are alternative stories that can explain why 3D headsets, in particular,
failed, independent of SRI tests etc.

Computers were much slower, and the visual update speed (presuming gyroscopic
control) likely lagged the rendered 3D view quite badly - and IMHO this is a
much worse problem that could cause motion sickness, but need not apply to 3D
video displayed on a flat surface in a fixed position relative to the viewer.

3D headsets also have significant usability and social use problems. They may
be heavy, tiring to wear, bulky, tedious to transport, geeky and exclusionary
to use. They may even leave one open to practical jokes, as they may act like
a blindfold; or unpleasant surprises. I know my gf hates it when I surprise
her when she's wearing headphones.

3D video, meanwhile, normally requires that everyone wear special glasses.
That's a fad that gets tired pretty quickly, and turns TV into a more binary
watching / not-watching experience.

Personally, I'm not particularly afraid of gaze focusing issues arising from
3D video. I am, however, quite skeptical that it will ever be more than a
gimmick that fades after a year or two of hype, while it still has accessory
and viewing angle requirements.

------
miguelpais
I just hope that ten years from now 3D televisions won't have become the
standard to the point of buying a regular HDTV being impossible.

I mean, 3D is nice for a change but I just feel like it was the new way for
companies to create another high priced product to make people want to replace
their already expensive and recently bought TVs without that much value being
added to the product.

~~~
nitrogen
Since current 3D TVs also make decent 2D TVs, I don't think it'll be such a
bad thing. If you're only interested in 2D, you could theoretically pass
double-rate video marked as 3D, and get a 120Hz refresh rate. I don't know how
HDMI 1.4 signals 3D vs 2D video, though, so you may need a video card (or
dongle) that can send the right signal and/or flip the right bits in the HDMI
signal.

------
thefool
The reason he gives for 2D monitors being bad for your eyes is spot on.

However, it seems to me that these would actually be better because they would
make your eyes change thier depth of focus more.

Looking at sterograms can actually improve your vision by strengthening eye
muscles that aren't frequently used in our computer - don't go outside and
change focus much - age.

~~~
teilo
When viewing 3D video, _depth of focus does not change._ That's the issue. 3D
breaks the association between focal distance and convergence. It forces a
constant focal distance while the convergence point varies. It's not normal
for eyes to work this way, and it does cause disorientation, mild in some,
stronger in others.

Whether this is a serious issue or not, time will tell.

~~~
lutorm
Thank you for actually spelling out what exactly they were complaining about,
and I can see how this would be an issue when viewing a monitor. However, you
don't have to go to very large distance until the focal distance is
effectively infinite.

So I guess the moral of the story then is to combine the 3D technology with a
projection system that puts the image at close to infinity (like
<http://www.mikesflightdeck.com/Scenery_display_2.htm>).

I've played around with this lens approach for flight simulators, and I have
to say that having the image near optical infinity makes a much larger
impression than you might think. You are actually looking _through_ the
screen, not at it. The quality isn't great, but it greatly adds to the feeling
of immersion. I think this is more important than 3D, since stereoscopic
vision really only works at quite short distances.

~~~
thefool
Indeed, the other solution is true holograms, that people have been playing
with for years.

Those actually physically have the light reflect to your eye from different
positions in the "z" direction.

They seem to have a number of techical problems though that would prevent them
from being ubiquitous.

------
maqr
I keep seeing these stories, but all of it sounds like pseudoscience nonsense
to me.

------
lutorm
Incidentally, I experience this every time I put in or remove my contact
lenses. Because they are in a different position than my eyeglass lenses, the
refraction affects image distorsion such that for a few minutes afterwards
(especially if I am outside looking at large distances) it's somewhat
disorienting.

It's not obvious to me that the "risk" talked about in the article is real,
though. It seems that what they talk about in the article is that strabismus
is when your stereoscopic vision does not develop because one eye does not
align properly to your viewpoint. This is fundamentally different from the
fact that your 2 eyes have to align slightly differently when viewing 3D video
compared to the normal world. If you have strabismus, 3D video just won't
work. It seems like a stretch to say that because you have to shift your aim
point, you will lose the ability to align your eyes properly completely. In
fact (like barrkel hinted at, too) it seems like this would be _practice_ ,
not detrimental.

But this is obviously only speculation on my part...

------
Groxx
After reading: <http://news.ycombinator.com/item?id=1406714>

Sounds like it may be a way to turn your kid into an artist :D

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petercooper
In order to respond to this post with the level of seriousness it deserves, I
have prepared my true comment in a visual form:

<http://skitch.com/petercooper/dkny7/3d>

