If you weren’t blown away by the three-dimensional effects in James Cameron’s movie "Avatar" or you left the theater with eyestrain or a headache, your eyes might not be 3D-ready. Around 5 to 10 percent of people don’t have true depth perception, and far more may have trouble with their binocular vision, which is needed to see the 3D images in movies or the new 3D TVs on the horizon.
To make movies such as Avatar, filmmakers use special 3D cameras that capture two images, simulating the different perspectives of the left and right eye, according to RealD, a 3D technology company. The two slightly different images are projected onto a custom screen. When seen through the lenses of the special 3D glasses, each eye sees the proper perspective and the brain fuses them into a 3D or stereoptic image. Most of the new 3D TVs coming to market require shutter-style eyewear that blink on and off rapidly so that each eye sees its own, slightly different image.
People whose eyes aren’t perfectly aligned because of strabismus (the eyes don’t align when focusing) or amblyopia (the loss by one eye to see details), or who struggle to keep their eyes lined up and moving together, will likely have difficulty fusing the images into a 3D experience. Moreover, the challenge may cause eyestrain (dry, irritated, or painful eyes ), which may lead to headache.
Bottom line: If you’ve experienced problems viewing 3D images, you’re better off going to 2D versions of movies and watching TV on conventional sets. To try to determine why you’ve had 3D vision difficulty, consider making an appointment with an eye care professional—either an ophthalmologist or optometrist—and ask for an eye exam, including an assessment of your stereoptic vision. Some people who have 3D vision problems may simply need new prescription eyeglasses or
contacts, or might need to get their existing prescription changed. Some might be candidates for surgery to correct misaligned eyes. Also consider asking about a referral to a developmental optometrist, a practitioner specially trained to help patients improve their visual performance, which can help with tasks such as seeing 3D.
—Doug Podolsky, senior editor
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