Depth Perception (or lack thereof) and 3D Movies

Many moons ago, I learned from the Florida Department of Motor Vehicles that I have practically no depth perception. An optometrist later expanded on this by noting that I have 20/40 vision in one eye and 20/100 in the other, and stated that my brain essentially ignores input from the bad eye. This results in monocular vision, and no depth perception.

However, I recently went to a 3D movie - and was blown away. I could see objects popping off the screen and I had a sense of depth that I had never experienced before.

Wikipedia has a brief blurb about this effect here: 3D film - Wikipedia. Or go to wikipedia and search for “3D Film”.

If you look at the first paragraph of the “Polarization Systems” section, last sentence, it states that people with amblyopia (one dominant eye) can see 3D this way. However this contradicts what some semi-serious Googling finds for me.

Can anyone verify this information?

My father has fairly strong amblyopia. I was surprised when he said that he could see the stereo effect in 3D movies just fine. (pretty sure he has only been to 3D theaters that use polarization)

I have a similar problem, and I too can see 3D.

I, too, have a severe lazy eye (amblyopia) and have no depth perception but can see the 3D effects in the latest 3D movies. I cannot see them with the old-style red/green or red/blue glasses. I am still incapable of seeing anything in Magic Eye pictures.

Odd, some artcle about 3D movies and TVs said that one impediment to public aceptance was that something like 10% to 20% of the public was unable to see the 3D effect for various vision reasons.

Another problem is - how 3D are these movies? I can see that someone could have difficulty with 3D when the subject is 20 feet away, but something 2 feet away would be sufficiently distinct in either eye to trigger the 3D perception. If the “eye separation” in 3D is really wide (to get the “popping out of the screen” effect this would be the equivalent of an object within arms reach.

Another study I read about, done for the Imax developers, found that beyond about 20 feet depth perception was irrelevant. Beyond that distance, realism was achieved by extremely high resolution and a high frame rate that avoided the stroboscopic effect.

It is a myth that depth perception in the real world depends entirely, or even mostly, on combining the image from two eyes (binocular disparity). In fact, this is only an important source of depth information for things that are fairly close to us. Much of the depth and distance information that our brain uses, especially for thing further away (at the sorts of distances that matter in driving) comes from the parallax induced by small motions of the head or even of the whole body (and this does not exhaust the sources of depth information that the brain makes use of). This is why the 3D of of 3D movies (which work entirely upon binocular disparity) does not actually look very natural to most people. It also means that one eyed people can see depth, to a considerable degree, in real world conditions, even though 3D movies will not work for them.

I am not sure exactly how your depth perception is affected by your condition, or whether the Florida DMV is justified in banning you from driving because of it. If the condition does significantly affect your driving ability, that may have more to do with a lack of properly processed peripheral vision on the side of your bad eye than with lack of 3D vision. (On the other hand, it may be that whoever drafted the Florida driving laws does not have a very deep understanding of how depth vision actually works.)

I missed the edit window there, but re-reading the OP I see that you do not explicitly say that the Florida DMV actually banned you from driving.

Fortunately, the Florida DMV did not ban me from driving. The state I currently live in doesn’t even test depth perception, so I’m not prevented from driving. I seem to function pretty well without depth perception, though parallel parking is a nightmare.

What puzzles me is how this is even possible. The article on Wikipedia doesn’t seem to provide a good explanation of this effect, though I may just not understand depth perception well enough. I do understand that stereoscopy is only one part of depth perception. If it was, I would have significant difficulty functioning on the road. As it is, I’m a pretty safe driver.

This also brings up some other questions. In my reading I have learned that there is some disagreement whether adult amblyopia can be cured. Some doctors recommend certain visual “exercises” to correct the problem. My fiancee even suggested getting a 3D monitor as one form of this exercise.

Anyway, some sort of semi-scientific explanation would be helpful.

imrazor didn’t say he was banned from driving. Back when the eye exam at the MA DMV included a check for amblyopia I always failed but was never banned from driving. My license simply noted that I must wear corrective lenses while driving. There are no corrective lenses for my condition (at least not ones anyone would want me to wear while driving as they usually involve completely blocking out vision in the good eye) so I didn’t wear any and no police officer ever asked me about the restriction when I was pulled over. I have no trouble at all with depth perception when driving.

Well, clearly your ‘bad’ eye is not non-functional, but that does not mean that it is functioning as it should. It may be giving you 3D information that is inaccurate rather than non-existent, perhaps even exaggerating the 3D movie effect over what most people would experience.

I do not think anyone would be able to give a more detailed account of what is going on without access to much more precise and detailed information about what the issue is with your eye.

As far as I know the only issue is the imbalance in visual acuity. One eye is 20/40 and the other is 20/100. According to my original optometrist, my brain simply discards the blurry mess from one eye and uses the almost normal input from the other. That could be wrong, I suppose.

I’ve also had several eye exams over the years, and never has any optometrist told me I have any other eye problems.

Everybody has one eye that is dominant. “Amblyopia” means lazy eye. If that is the reason for the 20/100 vision in that eye, it cannot be corrected by glasses, and, I guess, that must be the reason else your optometrist would’ve prescribed glasses. Amblyopia occurs in childhood, and could easily be corrected when a child. Have you seen an opthalmologist about the possibility of having it corrected now?

I did not need glasses until I had my eyes tested around age 30 for a pilot medical renewal. My doctor said it was age, i blamed working with computer screens.

Anyway, because of mild near-sightedness, I had gotten into the unconscious habit of judging distance by using relative blurriness, especially in indoor lower light situations. When I first got glasses, and put them on inside the mall, it was “information overload”. Stuff 200 feet away that had been relatively blurry was suddenly in sharp focus and seemed to me to be only 5 feet away.

So I’ll agree with depth perception being a subtle combination of various cues and experience, all analyzed subconsciously.

The optometrist did prescribe glasses, and I still use glasses to drive. If I remember correctly (and it’s been a very long time), the optometrist seemed to think wearing glasses to correct the imbalance would sort out the amblyopia. It never did.

Since seeing the 3D movie, I have been considering seeing an opthamalogist. Not sure it would be worth the time and effort to correct, since I seem to function without too much difficulty. It would be great though if “reality” looked as good as one of those 3D movies…

Reality looks MUCH better than those 3D movies.

I have the same problem, and I can see 3D (haven’t been to any of the new movies, but never had trouble with the kind they have at amusement parks.) I can’t see Magic Eye pictures, though.

Amblyopia can be corrected in youngish children by covering the good eye with a patch, which forces the weaker one to do the work and establishes the right brain brain pathways (the problem is in in the brain, not the eye itself). My daughter had to do this a few years ago. However, an adult brain is not nearly so plastic as a child’s, and I think the condition is considered incurable in adults.

It does not mean that your eye does not work; it just means that your brain is not making as effective use of it as it could.

I think it is considerably more difficult for an adult to overcome, but isn’t necessarily incurable. Found this story on NPR about a neurologist who cured her amblyopia

I’ve read there are two types of amblyopia, strabismic and anisometropic (refractive). I suspect that an anisometropia problem can create a strabismic problem if an eyeglass lens fails to focus on an exact area of the retina that facilitates binocular “stereopsis”. Binocular stereopsis is like the brain’s ability to process binocular angular disparity perceived between the two binocular ocular images, thereby creating binocular 3D space perception. After the lens magnification problem is corrected, I believe that eye exams should have much more extensive 3D tests than they generally do now for proper lens alignment. The eye doctors who I’ve known do not seem to have their acts together on this.

If you can see 3D movies but have predominantly monocular vision, then perhaps the lens focus isn’t too far off from the exact area on the retina that stimulates stereopsis - like a bell curve as you get your focus closer to that less-than-2mm area.

Binocular stereopsis enables a person with normal vision to see the 3rd image (aka magic eye image) that is embedded in a 2D stereogram. If you have monocular or predominantly monocular vision, then you can’t normally see the 3rd image. I suppose many people with amblyopia or strabismus also have latent binocular stereopsis. A pair of prism glasses from a 3D store might allow you to see the magic eye stereogram images. I suppose this would depend on how bad your suppressed eye really is. Prism eyeglasses might also work with colored or polarized 3D viewing glasses - you’d have to experiment with them to know for sure.

There are other depth perception cues which are monocular. And everyone seems to have space/depth perception. Even blind people.

For me, an interesting remedy for “deeper” space/depth perception in everyday life has been obliquely linear polarized glasses. I use them like sunglasses. These create a “polarization disparity” which, I believe, somehow relieves the suppression instinct and creates a better balance between all available depth perception cues. For me the world now seems less flat in front of my eyes. Trees, leaves, branches, objects suddenly seem to be out there in 3d space. I posted about this a year and a half ago on the Usenet, “Mundane Depth Perception Remedy”. I just found in the wiki article on stereopsis which would implly that this polarization disparity might create so-called “shadow stereopsis”:

“In 1989 Medina demonstrated with photographs that retinal images with no parallax disparity but with different shadows are fused stereoscopically, imparting depth perception to the imaged scene. He named the phenomenon “shadow stereopsis.” Shadows are therefore an important, stereoscopic cue for depth perception. He showed how effective the phenomenon is by taking two photographs of the Moon at different times, and therefore with different shadows, making the Moon to appear in 3D stereoscopically, despite the absence of any other stereoscopic cue.[footnote]”

From this I wonder if there is actually a small amount of monocular stereopsis in each eye. If there is, it would be based on a much smaller amount of parallax (less than, let’s say one millimeter) than binocular parallax (about 65 millimeters).

A linear polarization disparity happens with everyday objects because most reflected light from objects are in some way linearly polarized. The differentially polarized lenses should help detect this, and a polarized monocle might also work to some extent.

I more recently read about “Stereo Sue”. Her vision problem was mainly strabismic. Her lens refraction was a pretty good 20/40 in each eye. In the next edition of her book “Fixing My Gaze”, I’d like her to include a list of her eye doctor and psychiatry bills. Just because the eye doctor regime failed to aim our eyeglasses right.

with a strongly dominant eye you may have poor binocular depth perception but you still have depth perception.

people with only one eye can have driver’s licenses.