Although no one knows exactly how many, some people who watch 3D images on television, at the movies or while gaming suffer symptoms such as blurred vision, headaches, nausea and dizziness. This is especially true in movies that use quick cuts between scenes with different depths, forcing our eyes to make constant adjustments to focus on images that are simultaneously near and far away—something good directors try to avoid.
Margaret S. Livingstone and her colleague, Bevil R. Conway, at Harvard Medical School have published a study in The New England Journal of Medicine, that suggest Rembrandt may have been stereo blind since he appears walleyed (divergent strabismus) in his self-portraits. If it's true and his eyes didn't align correctly,
his brain would have compensated, using only one eye for visual tasks. This may have allowed him to better see the world in two dimensions and then reproduce the
scene that way on a twodimensional canvas. The two researchers expanded their study using photos of more contemporary artists and suspect that others may also
have been stereo blind including de Kooning, Johns, Stella, Picasso, Calder, Chagall, Hopper and Homer.
A small number of people can't see the 3D effects at all. The Optometrists Network (www.vision3d.com
) explains that several visual disabilities make seeing in 3D difficult or impossible. These include loss of an eye, amblyopia (lazy eye), and strabismus (eye turns, crossed eyes or wandering eyes). In most cases two-eyed vision can be improved with supervised visual therapy.
Because 3D manufacturers are aware of these potential problems, they often put warnings on their products. For example, Fuji puts this somewhat alarming warning in their owners manual for the W1 and something very similar in the manual for the W3:
3D display is not recommended for young children (up to the age of about six) whose visual system is still maturing and for individuals with notable differences in vision between their two eyes, who may find it difficult or impossible to observe the 3D effect. Should you experience fatigue or discomfort while viewing 3D images, cease use immediately. A ten-minute break is recommended about once every half hour. Switch to 2D immediately if 3D images still appear double after you have adjusted parallax. Individuals with a history of photosensitive epilepsy or heart disease or who are unwell or suffering from fatigue, insomnia, or the affects of alcohol should refrain from viewing 3D images. Viewing 3D images while in motion may cause fatigue or discomfort.
If you have trouble seeing in 3D you may want to meet Susan R. Barry who was cross-eyed and stereo blind since early infancy. After half a century of perceiving her surroundings as flat and compressed, Barry found an optometrist who prescribed a little-known program of vision therapy. After intensive training, Barry was ultimately able to accomplish what she and other scientists had once considered impossible—the return of her 3D vision. As a neuroscientist, she understood
just how extraordinary this transformation was, not only for herself but for the scientific understanding of the human brain. Scientists have long believed that the brain is malleable only during a "critical period" in early childhood. According to this theory, Barry's brain had organized itself when she was a baby to avoid double vision—and there was no way to rewire it as an adult. She tells her story of how she overcame this disability in her book Fixing My Gaze.
Chico: Hey, boss, what's-amater
you no longer make-a eye contact?
Grocho: None of your strabismus
President Ulysses Grant at his cottage by the sea (top) showing Grant seated on porch with his wife, Julia, and son, Jesse. View of the entire cottage (bottom).