In my last article 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
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