Do your eyes get fatigued, blurry, itchy, or sensitive to light when computing? If so, you’re not alone. Several studies over the years have shown that one or more of these visual symptoms occurs in 75 percent to 90 percent of people working at a computer.

You don’t even have to be tied to your computer. All it takes to develop symptoms such as these is 2 hours a day of computer use, according to the National Institute for Occupational Safety and Health (NIOSH).

There’s even a clinical name for it: Computer Vision Syndrome (CVS). Three times as many people experience CVS as the more well-known carpal tunnel syndrome, according to NIOSH.

“The characteristics of computer screens and the visual demands of computer work make many people susceptible to eye- and vision-related problems,” said Dr. Jeffrey Anshel, author of three books and editor of another about eye care for consumers and ergonomic specialists.

Anshel, who also runs a private optometric practice in Carlsbad, Calif., shared some tips on preventing such problems.

Adjust the Position of Your Monitor

The biggest cause of eye problems is placing the monitor too high, said Anshel. Our eyes work better and focus more accurately when they’re looking slightly downward rather than straight ahead.

You should place the monitor so that if you look straight ahead, you’re peering just over the top of the monitor, then you should slightly angle up the monitor.

Along with fatiguing your eyes, reading a computer screen while looking straight ahead can also dry them out, since your lids will have to be more widely open. If you wear contact lenses, the eye dryness will become more exasperated.

People blink about one-third the normal rate when using a computer, said Anshel, because they’re looking up and concentrating, which also contributes to dry eyes. Even though blinking is largely reflexive, try to keep aware of the need for it.

Your monitor should also be no closer than arm’s length from your eyes.

Pay Attention to Surrounding Lighting

To avoid glare or shadows caused by nearby windows, and the resulting eyestrain, don’t compute while facing an unshaded window or with an unshaded window directly behind you. Shades, blinds, or curtains can help. The best window position is to the side of your computer. If reflections are still a problem, an anti-glare screen placed over your monitor can help.

When computing, if you typically view dark text on a light background, the room lights should be brighter than if you typically view light text on a dark background. If you can’t adjust the lighting, consider wearing a visor to shield your eyes from it. Light text on a dark background can be easier on your eyes.

Take Eye Breaks

Our eyes aren’t designed to see at a close distance for hours at a time without interruption, said Anshel. If you keep your eyes focused on one particular point for an extended time, the lenses of the eyes will get stuck at that focal point, which, among other things, can cause squinting and eye-muscle fatigue as well as problems reading street signs at night.

He recommends the “20/20/20 rule.” Take a 20-second break every 20 minutes, focusing your eyes on points at least 20 feet from your computer screen. Keep your eyes moving while looking at objects at various distances.

Wear the Right Glasses

If you normally wear glasses or contact lenses and are older than about 45, you may need special vision correction for computer work. Computer screens are neither at a close distance typical of reading nor a far distance typical of driving; rather they are at an intermediate distance.

Regular bifocal glasses can cause problems when computing, as can glasses with progressive lenses because the intermediate zone is too narrow. If you’re nearsighted, a work-around is using older glasses with a weaker prescription.

A better solution is to get glasses that are specifically focused for the intermediate distance of computer screens. The best solution, said Anshel, is “occupational progressives,” which are glasses that provide correction for near and intermediate viewing rather than the near and far viewing of normal bifocal glasses.

Anshel offers lectures and seminars to organizations on topics related to vision health and comfort and is a consultant for Johnson & Johnson Vision Care, Inc., which makes contact lenses.

He and Johnson & Johnson have put together a quiz Web site called Eye Q’s & Views (http://www.acuvue.com/oasys_pr/computerquiz.html), where you can get additional tips on preventive eye care in front of the computer.