Friday, October 14, 2011
3D Technology Revealing Vision Issues
LINCOLN, NE (NET Radio) - Video produced in three dimensions is intended to give the viewer a sense of depth and space that two dimensional video doesn't. State of art technology is putting 3D in front of eyes in more places than ever before. Movies, video games and television can be watched in 3D. Much of it now doesn't require the special 3D glasses of previous generations for the experience. As 3D becomes more common place, optometrists around the state say it could be impacting vision health.
3D has been around for more than 50 years, but when the animated movie Avatar was released about two years ago, it was produced with the latest cameras intended to revolutionize the movie-watching experience. For Omaha optometrist Dr. Corey Langford, it brought two new patients.
"I had two patients who came in who were young adults who never really had eye care because they could see fine and they were functioning fine along in the world but, noticed they couldn't appreciate or get what was going on in the 3D movie. They didn't see things coming out of the screen, they just didn't look right and all that kind of stuff, those were the kind of complaints that I heard. Sure enough when we took a look at their vision and what was going on with their eyes, they had one eye that didn't see as well as the other and they had no idea. Their vision was their vision and they never knew that it wasn't right or that it wasn't accurate until I showed them what the difference was when it was corrected."
The sense of depth or things coming out of the screen is one of the effects that supposed to make 3D a remarkable visual experience. But for some, 3D is bringing attention to a problem with binocular vision. For most, Langford says, when binocular vision is working correctly, the image each eye sees is made into one.
"Those two eyes get two different images and our brain has to put that into one image and that's part of what gives us three dimensions in our vision out in the real world. When you take away the need for the brain to fuse objects when you cover one eye, our eye muscles go to a relaxed position called the Phoria position. When both eyes are uncovered your brain can just take the eye muscles and make a little adjustment and have one single image instead of double vision. The extreme case where that goes wrong is where people have a big eye turn or cross-eyes or an eye that wanders. Those are extreme cases, those people don't have any binocular vision but they have poor depth perception and things like that, they certainly have, wouldn't be able to appreciate 3D technologies that were talking about."
Langford says good binocular vision is also important for reading as it helps the eyes move smoothly across a page.
When reading became painful for Elizabeth Perkinson of Bennington, she found out what binocular vision problems are all about. It became painful for her to read. "My eyes just felt like a pulling like a muscle strain. Not only do my eyes have a strain and a hard time pulling things together vertically but also horizontally, and so that was causing a strain on my eyes when they have to work together especially for reading."
Dr. Langford explains the role binocular vision has in reading. "Binocularity is extremely important to read smoothly, for your eyes to perform the movements they need to perform when they are going across a page to keep words single and clear, for longer periods of time. So in our world today, it's not uncommon for me to have a patient say I sit in front of a computer 10 hours a day, binocularity is extremely important. You need to be able to comfortably keep your eyes focused on things at near in this world and that's where we see a lot of problems."
A stay-at-home mom from Bennington, Perkinson's eye exam with Dr. Langford identified not really a vision problem but a eye muscle coordination issue similar to that some are experiencing after viewing 3D. Perkinson now wears glasses. "He prescribed me some glasses that have very little to no correction but they have a prism in them and I don't know exactly how it works, but it works and it helps my eyes to bring things together. As I wore them I've kind of become addicted to them and used to them and I wear the basically all the time now because when I take them off my eyes kind of go yikes! I like it better when they are on and it's almost like my eyes are able to relax and be in their natural place and so I can get along fine."
Dr. Langford also remembers a patient coming in to check to make sure his 3D vision was precise for an important function in the workplace.
"I just recently had a gentleman come in who works for the govt. as a cartographer he looks at these 3D map images that come from Afghanistan and Iraq and to identify targets for missiles to hit. He has to be very precise in what he's looking at and where it's at. 3D is a huge part of his job and if he doesn't have good 3D vision, and that's why he came to me to verify that he had good 3D vision, he can't have his job, so that's just one example, a fairly extreme example but one that's important because you want to hit your target."
The Nebraska Optometric Association wants educators to be aware of the issue, not just because vision is critical to learning in general, but it anticipates more 3D technologies will come to the classroom as learning tools. With more learning and professions based on computer use, Dr. Langford says there are simple steps to avoiding eye strain from overuse of computers and hand-held devices. It can be done as easy as a blink of an eye.
"That sounds like the dumbest thing to tell someone, like to tell someone to make sure their heart beats, because we blink involuntarily, however we know that when people are concentrating they blink less, when they are on the computer they blink even less than that. For example we typically blink about 16 times a minute, people who are on the computer screen tend to you blink about 6 times a minute. So you aren't refreshing tears across your eyes, your eyes can dry out and that contributes to tired eye feeling The other thing we tell people is to take visual breaks meaning that our eyes have to work the most when they look at things up close, they are the most relaxed when they look at things that are at least 20 feet away. So every 20 minutes look at something at least 20 feet away and if you can't get that in focus, then you need to take a break."
Otherwise, optometrists are seeing 3D as a way for consumers to identify minor vision problems they possibly never knew they had.
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