In my last article in EXCELerated Vision I described a condition known as “stereo blindness” which affects many children and adults. Thanks to Avatar, binocular vision problems that cause stereo blindness are now gaining more public awareness. Yes, the stereo blind individual not only “can’t see it” (3-D), but for 165 minutes of this movie they will have a “blurry” or “smeary” visual experience. Thus, for the stereo blind, Avatar is just not enjoyable because it just looks out of focus.
However, for those who have another common binocular vision problem, Convergence Insufficiency (CI), Avatar may make them sick! Yes, Avatar can actually be a “health hazard” for those with weak binocular vision ability.
Unlike the stereo blind individual, those with Convergence Insufficiency (CI) actually can use their binocular vision, however they just use it very poorly. For example, in a normal daily reading task, the child or adult with CI will have trouble coordinating their eyes to look at near. They will experience eye strain, fatigue, words overlapping (double vision). Therefore the person (with CI) will simply get away from it and avoid the visual task. In other words, they respond to this “reading a book discomfort” by putting the book down.
On the other hand when this same person enters the theater to watch 3-D Avatar they are faced with a giant screen and for 165 minutes, they experience highly stimulative 3-D images. For the person with normal binocular vision, this 3-D Avatar experience is nothing short of spectacular. But for the person with poor binocular vision (CI) the Avatar visual extravaganza results in an over stimulation of their visual system often resulting in headaches, nausea and dizziness. In essence, Avatar will make them sick!
While 3-D Avatar is no doubt one of the most entertaining films of all time, there is still a risk that this movie can cause illness in those who have certain visual problems. The good news is that 3-D Avatar can serve an important service to the public health by alerting those with binocular vision problems. Anyone who experiences illness from this film should see their primary care eye doctor, preferably a doctor who is experienced in the diagnosis and treatment of patients with binocular vision problems.
If Avatar makes you sick, it is important to know that binocular vision problems like Convergence Insufficiency can be successfully treated though office-based optometric vision therapy. Just like in the movie…for the patient with CI, there can be a happy ending!
Dan L. Fortenbacher, O.D., FCOVD
Mindsight 
Thanks for the clarification Dr. Fortenbacher. I guess this is a situation in which I should be grateful for the complete suppression in my amblyopic eye.
Hi – I’m mystified by your comments that
“the stereo blind individual not only “can’t see it” (3-D), but for 165 minutes of this movie they will have a “blurry” or “smeary” visual experience. Thus, for the stereo blind, Avatar is just not enjoyable because it just looks out of focus.”
I have absolutely no stereo vision – amblyopic since I was 2, I’ve had 2 surgeries and still my eyes are misaligned, never have experienced convergence and I totally suppress the vision in my right eye. I’ve seen Avatar and lots of other 3-D movies and I of course have no 3-D experience, but as long as I am wearing the 3-D glasses I can see the screen just fine – no blurring or smearing. Blurring will definitely appear if the 3-D glasses are taken off, whether you have stereo vision or not.
I can understand how someone with reduced stereo vision or only a little bit of stereo vision could find the experience visually confusing or even nauseating, but you might want to rethink or reinvestigate your sources on the experience of seeing 3-D movies with monocular vision.
Hi Deborah,
Thank you for your comment and yes you are also correct. Some people with more severe forms of amblyopia and/or strabismus will have NO problem with a confusing “ghost image”. Like most things, stereo blindness is not an all or none type of condition. It can be mild, moderate, severe or none (zero) depending on the patient. From what you described, it sounds like you fall into the later category. However, those who have mild to moderate stereo blindness, watching a 50’x70′ IMAX screen with images that are supposed to be seen with both eyes simultaneously, will experience a smeary or blurry type of visual experience. That is because these folks (with mild to moderate loss) typically can suppress the central portion of their vision but can not ignore (shut down) their peripheral vision on the big screen. Therefore the “ghost image” prevails. It sounds like you have successfullly learned how to completely “shut down” the image from your amblyopic eye. As a result, no problem, visually speaking, with the 3-D Avatar…you are just NOT aware of what you’re missing. Thank you again for raising this important point.
Thanks, Dr. Fortenbacher, for the excellent post. I’m anxious to see the movie now!
Hope Avatar’s movie fans who get sick heed your advice.
Optometrists who are members of COVD are board certified in binocular vision care and will be able to treat vision problems such as convergence insufficiency.