June 16, 2000 -- No matter how much computer manufacturers use color or design to make their products less of an eyesore, they've still got a long way to go to make a computer user's eyesless sore.
The hands aren't the only ones to carry a heavy workload at the computer; the eyes do, too. But, whereas computer keyboards can cause real damage to a person's hands, video display terminals by themselves can't harm a person's eyes.
"One of the things that people get concerned about with VDTs or CRTs is the amount of radiation that's emitted, and the amount is so small in the computer terminals made today that it wouldn't cause any kind of injury to the eye," Ned Witkin, MD, tells WebMD. He is director of the vision rehabilitation service and assistant professor of ophthalmology at Emory University Eye Center in Atlanta.
The amount of ultraviolet radiation, in fact, is actually a small fraction of that produced by fluorescent lights. The biggest complaint Witkin often hears is eyestrain from staring at a terminal a foot to a foot-and-half away for all hours of the day. That can cause dryness, itchiness, headaches, pain around the eyes, even blurred vision.
"Usually it clears within a few minutes. It's just basically the focusing mechanism inside your eye, it kind of gets stuck," Witkin says.
But what if the focusing mechanism stays stuck? Is the computer to blame now? Not really, says Witkin. All the computer is doing, really, is bringing to light a problem that might have already been there.
Some people may have been predisposed to vision problems before they started using computers, but since they weren't doing anything to tax their eyes, they didn't really know they had a need for glasses or contacts. But because using a computer can be stressful to the eyes, it can cause any hidden vision problems become glaringly obvious, according to Witkin. "It's what we call the use-abuse theory, because your eyes evolutionarily weren't designed to stare at a computer screen eight hours a day."
Witkin uses the example of a farsighted truck driver who became an airline reservationist. Farsightedness is a condition in which you are able to see distant things more clearly, but have more problems seeing things up close. In this case, being farsighted as a truck driver would not necessarily be a problem. However, in the up-close world of the reservationist, it would be a problem, and that person may now require glasses to work.
Then there's the problem of dry eyes, once again not caused directly by the computer, but by the habits of person who uses it. "It's not so much that computers cause dry eyes. They don't. But what happens is when you're staring at a computer screen all day long, you tend not to blink as frequently, and because of that, people who may have marginal dry eyes to begin with, it would exacerbate that problem," causing symptoms to develop, Witkin says.
Witkin tells people to use eyedrops if they can't make themselves blink more. There are drops supposedly designed for computer users, but Witkin says they're just a "repackaged form of artificial tears."
If you already wear glasses, there are lenses that are ground especially for computer users, called room distance lenses. They work from about 12 inches to 12 feet, but beyond that would be a little blurry.
Researchers studied one manufacturer's glasses that were designed for computer users, Witkin says. "We compared this computer-type lens to standard single vision lenses that were used to help patients see close-up or at intermediate range. The results were pretty compelling," he says. "About 88% of the people preferred this computer lens."
There are a few simple steps anyone can take to make computer use easier, says Witkin. Place the screen about a foot and a half away, and then tilt it down so you're actually looking down at it -- 15 degrees below horizontal to be exact. Ergonomic specialists also suggest the top of the screen be at or just below eye level.
Some tips to minimize eye strain caused by using a computer are:
- Remember to blink frequently;
- Use artificial tears;
- Keep the screen one to one-and-a-half feet away;
- Tilt the screen downward about 15 degrees, with the top of the screen at eye level;
- Consider room distance lenses.