The 3-D revolution, which only took about half a century to arrive, means many of the movie images we see today will be popping off the screen.
Can our eyes take it? And can everyone appreciate the snazzy new 3-D effects?
WWTW checked in with optometrist Dr. Jeffrey Anshel to find out more about how 3-D technology works – and if we should be worried about any potential eye strain it might cause.
Dr. Anshel, who has written numerous articles and books regarding nutritional influences on vision and computer vision concerns, is a VSP Vision Care provider and the principal of Corporate Vision Consulting. He maintains a private practice in Carlsbad, CA.
WWTW: Can you briefly describe how 3-D movies today trick us into thinking images are popping off the screen?
JA: We see in three dimensions, or technically called “stereopsis,” because we have two eyes that are separated by a certain distance. The further apart your eyes are, the more “depth” objects will appear to have. What 3-D movies do is to show each eye a different image and separate them by a certain distance to enhance the perception of depth. If you view the movie without the glasses on, it will appear with “blurred” edges around each image on the screen
WWTW: How are today’s 3-D visuals different than those from the past (like “House of Wax”)? Is it more or less of a strain on the eyes?
JA: Ah yes, “House of Wax” was a classic! In those days, the technology was much simpler- the two images created were just different by color, with one image being red, the other image blue or green. These two colors are on opposite sides of the visual spectrum so they cancel each other out. Therefore, it was thought that viewing one image in green and the other in red would be adequate to separate the eyes. However, about 8 percent of the male population is color deficient, so many more people had trouble viewing these colored images.
WWTW: Are there other reasons why some audience members can “see” the 3-D images, and is there any treatment or medication that could help them?
JA: About 5 percent of the population is “monocular,” which means that they only use one eye to see with. This can be because of “lazy eye” or trauma or for some other reason. They still have “depth perception” because they’ve learned how to perceptually know the spatial relationship of things (like a quarter is really smaller than the moon, but it can cover it if close enough to the viewer). Another 30 percent or so of the population has “borderline” binocular vision, which means that they can use both eyes together to perceive 3-D but they struggle at it. These are the people who will experience tiring, headaches or nausea during or after the movie. The only “treatment” for these people is to do a course in vision therapy – a program that helps people to learn how to better coordinate their eyes. Optometrists who specialize in “behavioral” vision can do this work.
WWTW: Do modern 3-D glasses pose any unnecessary health risks? How could they be improved?
JA: There are several different types of 3-D glasses, but they all serve to separate the two eyes to receive these different images. They really pose no external risk to the user, unless they decide that they want to try and drive at night with them on!
WWTW: Can watching a two hour 3-D movie leave a person’s eyes feeling strained or tired? How much 3-D should a person watch?
JA: There is likely no “maximum” amount of 3-D viewing to consider because each person will experience it differently. I think that a 2 hour movie is fine but going into 3 or more could lead to eyestrain.
WWTW: Is the dawn of 3-D TV a possible problem for our culture given it could mean extended viewing of 3-D material?
JA: Since there are several different technologies being used for 3-D, it’s likely that one or more of them could take hold and be the “default” technology for the general public. However, when considering television, having enough glasses for everyone at the party could be a problem. There may come a time when these are personalized (several companies are currently working on prescription versions) glasses might be another offering for eyecare providers. Or maybe a version of 3-D that does not involve eyeglasses at all will take hold – that is also in the pipeline.
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