No stereo vision but I can see the 3D effect in 3D movies ??

I had a turn in my eyes when young - an attempt was made to correct this with glasses, which was not fully successful. I've had no surgery, and still have eyes which look at different points.

I can't see the 3D images in the Magic Eye books, I have trouble parallel parking, and I gave up flying a paraglider partly because I was so nervous flying with others (not being able to judge my position in the air in relation to them), and so bad at judging where I was going to land.

But last year I asked my optometrist to give me glasses which would force both eyes to focus on the same point. He was very sceptical they would do anything for me, and repeated the line that 'the brain can't process stereo information as an adult if you couldn't as a child'. I've also been doing some work myself with the Brock string and red-green filters. But as far as I could tell I'd been making no progress towards stereo vision.

Then a couple of weeks ago I took my son to see a 3D movie. I put the 3D glasses on over my eyeglasses, and to my surprise I saw the movie in 3D (it was 'Puss in Boots').

I don't understand why I can see a movie in 3D, but not real life. I assume a 3D movie is not 'real' 3D and somehow I can see it. Or, it may be a sign I am getting some stereo vision?

If anyone has explanations or similar experiences I'd love to hear them.

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Hi Rob, this is fascinating! I don't have explanations so much as a couple of ideas: if the movie was RealD and you are an alternator, it will come across as monocular with perhaps a bit of flicker, but with ramped up motion parallax and optic flow which are non-stereo spatial cues.

Or it could be you are Brocking enough that you are getting some real stereo, which would be awesome.

I did a blog post on this awhile back here: You've encouraged me to check out another movie. I'm thinking Hugo would be a good one!

Lynda -

Thanks for the information and links, and as it happens I've just seen 'Hugo' !

Again I managed to view in 3D - the falling snow and falling ashes effects were particularly striking. The cinema uses the Dolby system.

It did occur to me I might just be seeing the motion parallax simulation, but it seemed to be more than that.

I'm wondering if I'm now 'getting' 3D but only beyond a certain distance - say 80 feet or more. Of course, this would be about the distance of the movie screen, which is at a fixed distance away, even in 'close up' shots.  At a 3D movie your eyes don't have to keep adjusting for distance, as they would in real life....

I've been wearing my adjusting glasses, for about a year, so maybe my brain is learning to combine, starting with distant images....

I may have to check out Hugo with a Dolby system then!

I also agree that not having to converge and diverge in stereo may be a plus. But I also have read that the movies can cause headaches and other problems for folks whose stereo vision is less than stable.

I hope more people respond. This is a great topic! (And I would love to be able to see the Hobbit in 3D next December ...)

Hi Rob,

Have you had your binocular vision fully tested? One of the things I was very surprised to learn during my VT experience was that our ability to perceive depth (via binocular vision) is not just something we have or don't have, but a matter of degree. I began with no detectable depth perception, but have made great strides in the last two years. The unit used is "seconds of arc," where normal depth perception registers around 20-40 seconds of arc and 3D movies can be detected at somewhere around 200-300 seconds of arc. The bigger the number, the further the objects have to be from one another for you to detect the difference. 

That being said, I don't know if random-dot images follow the same scale. I've only very recently started developing any random-dot stereo at all, so I haven't asked nearly as many questions. 

Good luck!

Hi Anna -

I've only had 'oh dear' opinions from an optometrist, since I don't have access to a vision therapist.

As it happens I've just been rereading Susan Barry's book and I see now she also describes how binocular vision is a matter of degree, not all or nothing - so I'm sure you are right. Obviously from your information the 3D movies are exaggerating the '3D' for effect, so with my limited stereo capability I am able to see it.  I'll follow up on the random dot stereo too.

Many thanks for your helpful post!

Dear Rob,

Here's an idea explaining why you can see the 3D in the 3D movies.  The glasses that you wear for 3D movies alternate which eye sees the image at a very fast rate.  Then your brain must fuse the images seen at slightly different times by both eyes.  Under normal circumstances, you suppress the image from one or the other eye, but suppression may take time to build up, and the glasses may switch the image from eye to eye so fast that suppression doesn't have time to kick in.  If your eyes are aligned well enough for some fusion, then you may be able to fuse the two eyes' images and see the 3D.

Also movie theaters are dark, and suppression may be greatest under normal daylight conditions (when if you have misaligned eyes, you need suppression most to avoid double vision).  So the movie theater presents a viewing situation in which your normal strabismic adaptations may be less activated.  Perhaps, you might be able to see 3D in real life if you start by looking, let's say, at tree branches at night under a street lamp.  This is just a guess but I did notice that tree branches illuminated at night by street lamps gave me a wonderful 3D view. 

Sue, I'm totally liking your theory, and am very encouraged to give a 3D movie a try!

Actually, the alternation is true for one RealD 3D projection and glasses and not Dolby, which is simultaneous and uses color gamut to separate and fuse the two projections.

So it would be good to be informed which kind of 3D movies we are seeing and share any differences we experience.

Here's a bit of wiki-ness from an old blog post

Tech info on RealD from wikipedia

RealD 3D cinema technology uses circularly polarized light to produce stereoscopic image projection. Circular polarization technology has the advantage over linear polarization methods in that viewers are able to tilt their head and look about the theater naturally without a disturbing loss of 3D perception, whereas linear polarization projection requires viewers to keep their head orientation aligned within a narrow range of tilt for effective 3D perception; otherwise they may see double or darkened images.[2]

The high-resolution, digital cinema grade video projector alternately projects right-eye frames and left-eye frames 144 times per second.[2] The projector is either a Texas Instruments’ Digital Light Processing device or Sony’s reflective liquid crystal display. A push-pull electro-optical liquid crystal modulator called a ZScreen is placed immediately in front of the projector lens to alternately polarize each frame. It circularly polarizes the frames clockwise for the right eye and counterclockwise for the left eye. The audience wears spectacles with oppositely circularly polarized lenses to ensure each eye sees only its designated frame, even if the head is tilted. In RealD Cinema, each frame is projected three times to reduce flicker, a system called triple flash. The source video is usually produced at 24 frames per second per eye (total 48 frames/s), which may result in subtle ghosting and stuttering on horizontal camera movements. A silver screen is used to maintain the light polarization upon reflection and to reduce reflection loss to counter the inherent losses by the polarization filters. The result is a 3D picture that seems to extend behind and in front of the screen itself.[3]

Tech info on Dolby 3D from wikipedia

Dolby 3D uses a Dolby Digital Cinema projector that can show both 2D and 3D films. For 3D presentations, an alternate color wheel is placed in the projector. This color wheel contains one more set of red, green, and blue filters in addition to the red, green, and blue filters found on a typical color wheel. The additional set of three filters are able to produce the same color gamut as the original three filters but transmit light at different wavelengths. Glasses with complementary dichroic filters in the lenses are worn which filter out either one or the other set of three light wavelengths. In this way, one projector can display the left and right stereoscopic images simultaneously. This method of stereoscopic projection is called wavelength multiplex visualization. The dichroic filters in the Dolby 3D glasses are more expensive and fragile than the glasses technology used in circular polarization systems like RealD Cinema and are not considered disposable. However, an important benefit of Dolby 3D as compared to RealD is that no special silver screen is needed for it to work.

Sue and Lynda -

Thanks for the information, and it is starting to make sense for me now. I've confirmed it is actually the RealD system I've been seeing in cinemas, so the rapid alternation of images being the factor which allows me to see in stereo must be true.

Knowing I have some binocular vision, even at the poor end of the spectrum, is tremendously encouraging for me, and I will keep working at it! Including trying out the low light and artificial light experiences.  I hope this thread encourages others to try out viewing 3D movies too.

Same here, i can see the 3D effects in the cinema and on my passive LG lcd. Though it gets better when im nearer to the screen, and i believe my girlfriend and kid have a better perception of the effects. Better than nothing i guess... anyone here that has had any success with eye training yet, besides the well known book sellers out there?

Oh and i should mention that i have only 10% on my left eye... i can see only garbage with it. 

Funny, something like this happened to me recently. I don't think I fuse images completely (although I think that I'm getting to do it, very slowly). I don't notice anything especial about using both eyes instead of one, except for an increase of visual field: I'm not very aware of having gained any 3D vision at all.

However, watching 3D movies, I sometimes notice a little bit of depth here and there. It's only when it is something very obvious, an object getting very near the camera lenses.

Visual tests show that I actually perceive very little depth (although there is no doubt that I perceive some).

My optometrist told me to go to an IMAX theater, since their 3D system is supposed to be better than the one used in common theaters. I went to one IMAX 3D projection a few years ago, before therapy, and I saw nothing. So a few days ago, years after giving IMAX my first try, I went back to the same theater, without any particular expectation.

The lights went off, the screen was lit and then......



........................Oh, boy!

The letters from the IMAX logo were jumping from the screen towards me! It was amazing. I had never perceived 3D with such intensity. During many parts of the film (a documentary about the sea), I could clearly feel how many things moved in different levels of depth (especially floating particles in the water, which were there all the time) .

Two interesting things:

a) although I clearly recognise the effect of depth while watching the film, I can also feel it is not as important for me as for binocular people. I understand what it is and its meaning, and I enjoy it, but since it has never been an important part of my reality until very recently, it doesn't feel as real as it does to a binocular person. It's there, and it's nice and fun, but it doesn't make me move my head like "Hey, it's going to hit me!".

b) as Rob mentions, I don't feel like I'm seeing 3D in real life. However, I must be doing it. Otherwise, I wouldn't recognise the tridimensional effect in the film, would I?

Today I went to see the documentary Tornado Alley in 3D at the IMAX theater at the Houston Museum of Natural Science.  I could definitely pick up some 3D effects including, like you said, some of the logos at the start.  The clouds (there were many of them, it being a movie about tornadoes!) all looked more fat and puffy than they usually do to me, and so did the many silos of grain elevators shown in various shots of small towns.  I felt tremendous eye strain while viewing the movie. Fortunately it was only 40 minutes long not two hours.  There were also a lot of fast motion shots of vehicles driving past on roads and they made me very queasy. When I got up to leave and returned the glasses and went outside I felt very dizzy, too dizzy to drive, and had to sit and rest for awhile. In fact I then got a headache and had to take a nap. So I'm not sure this is an experience I am willing to repeat! Initially I had sat in about the middle and I felt I just had to move back as far as I could in the theater because the motion effects were making me too sick. After I moved back it was much better.

Funny, I've also felt uncomfortable while watching an IMAX 3D picture. However, it only happens during the first minutes: I feel seasick for some time and then, apparently, I get used to it, and the bad feeling is gone.

Two more points: although I perceive the relative differences of depth between objects on the screen, I cannot deduce a particular distance in relation to myself. A friend of mine said to me: "That was just one feet away!", and I was like "Really???". I think this happens because depth has never been a reference in my perception of the world. I recognize it, but I'm not trained to interpret it precisely. Practice, practice, practice.

I would also say that fusion seems easier for me while watching a movie than in the real world, although I couldn't say why. In everyday life I'm always switching between different ways of using both eyes, my sight is a little unsteady (although this doesn't bother me too much). I would say this is less so while watching a 3D film.



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