3D Video Hazardous to Your Health | Hacker News Reader

3D Video Hazardous to Your Health

audioholics.com

46 pointshernan719 comments

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.

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.

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.

Amblyopia is the condition where one of your eyes is ignored. Strabismus is a condition where your eye "turns", which can cause amblyopia if not treated. I had surgery a year ago for my strabismus, but the image from my weaker eye is still being ignored.

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.

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.

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.

Yeah, how many times as a kid did I hear "Keep making that face and it will get stuck like that!" I also recall my hands cramping into claws from playing Nintendo for hours and hours straight, and no RSI that I'm aware of, which seems like a much more realistic threat.

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.

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.

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.

My optometrist told me the following rule: 20-20-20

At least every 20 minutes look away from the monitor at something (the ceiling in the far corner, ideally out a window) at least 20 feet away for 20 seconds.

I have a pair of computer prescription glasses. They seem to have helped me vision from declining more.

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.

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.

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.

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

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...

After reading: http://news.ycombinator.com/item?id=1406714

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

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

Reply on news.ycombinator.com