TechTip: Protect Your Eyes Against Computer Vision Syndrome (CVS)

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If you work with computers—eyeing computer screens all day—you may be aware of the symptoms of computer vision syndrome (CVS), such as these discomforts:

  • Dry, irritated, or tired eyes
  • Blurred vision
  • Headaches
  • Neck- and backaches


In this article, the second in a series about avoiding repetitive strain injury, I'll show how to help your eyes relax.

Care for Your Eyes to Reduce Overall Stress

"The eyes lead the body," says James Sheedy, O.D., Ph.D., Dean of the College of Optometry at Pacific University in Oregon, and an authority on CVS. When we attempt a visually intensive task, such as viewing a computer screen, our bodies automatically position the head and eyes for that task, even if the rest of the body must contort awkwardly. Examples:

  • Wearers of bifocals tilt their heads back, raising the "reading" section of their glasses toward the part of the screen they want to see.
  • People with presbyopia (difficulty focusing on nearby objects) stretch uncomfortably back in their chairs so that their eyes are as far from the screen as possible.

We tend to adjust our posture automatically, not realizing what we're doing. Solution: Ask a friend to visit you occasionally at your workstation (unannounced, so you will act naturally), to notice if you seem strained or off-balance.

Dim the Glare

Glare is unwanted, irritating light that can interfere with your ability to see the screen. According to Dr. Sheedy, glare takes two forms: "discomfort glare" and "reflected glare":

Discomfort Glare

Discomfort glare is caused by bright lights in your field of view, including peripheral vision. Here's how to find out if discomfort glare is bothering you:

  1. Look at your computer display.
  2. Use your hands to block unwanted light sources, such as windows or the ceiling. (Most workplaces with overhead fluorescent lights cause some discomfort glare, according to Dr. Sheedy.)
  3. If, as your hands block the light, you feel a small improvement in comfort, then these lights were contributing to your discomfort.

Solutions: Reduce the unwanted light sources however you can (e.g., closing drapes, removing light bulbs); if overhead light is a problem, wear a visor; if you wear glasses, ask your optician about an anti-glare coating.

Reflected Glare

Reflected glare occurs when light reflects off your computer display, reducing the screen's contrast and clarity. Find out if reflected glare is reducing your screen's contrast:

  1. Use a file folder as a "light baffle," placing it above or to the sides of your screen. Temporarily block overhead lighting and light from windows.
  2. When you have blocked such light, can you see the display better?

Solutions: Select a computer monitor with glare-reducing features. According to Dr. Sheedy, liquid crystal display (LCD)—flat—monitors are less prone to reflections than cathode ray tube (CRT) models. In addition, try to block or reduce the unwanted light sources and move your workstation so that your monitor no longer catches the reflections.

One more tip to reduce the effects of glare: Protect your eyes during non-working hours. If you drive to work each morning, wear good sunglasses.

Keep Monitor at Arm's Length

The eye's muscles work hard to focus on nearby objects. To avoid strain, says Paul Linden, Ph.D., author of Comfort at Your Computer, monitors should be placed about an arm's length away from the eyes. "The resting focal length for the eyes in the dark is about an arm's length away. It takes muscular effort to focus closer than that."

Small handheld displays, such as Palm, BlackBerry, and Treo devices, present a new challenge. Containing small, densely displayed information, these devices seem to encourage people to bring these devices close to their eyes to make the information appear larger. The eyes need to focus and converge (cross) to see at such a short distance, increasing visual stress. If eyestrain should occur, Dr. Sheedy suggests, those affected should limit handheld devices to short-term use. Read long documents later on a larger screen.

Consider Occupational Progressive Lenses (Special Bi- and Tri-Focals)

Around age 40 or 50, many people lose their ability to focus on nearby objects, a condition called presbyopia. The typical solution is to get special eyeglasses, either a single prescription for near/intermediate vision or bi- or tri-focal (progressive) lenses, containing distance and near prescriptions in a single lens. Such eyeglasses, while helpful for general use, were not designed for using a computer all day.

According to Dr. Sheedy, computer displays are usually set up with an intermediate distance and angle that cause typical multifocal lenses not to work well. People who sit at a desktop computer in an office should consider occupational progressive lenses, which are ergonomically designed for such work. For example, an occupational progressive lens may have an intermediate prescription in its top half and a reading/close prescription in its bottom half. This configuration eliminates the need to crane one's head back. I've personally seen such a lens cure someone's neck pain and backache.

People who experience awkward posture due to the use of traditional progressive lenses could benefit from occupational progressive lenses. Here's a partial list of models:

  • Cosmolit Office
  • Essilor Intreview
  • Shamir Office
  • SOLA Access
  • Zeiss Gradal

Research such lenses, and then, if interested, ask your eye doctor or optician. These professionals may not bring up the subject but are likely to be helpful and knowledgeable when you ask.

Soothe Your Eyes Any Time

When your eyes feel tired or tight, you can give yourself a deep rest. This practice, commonly called "palming," takes only a minute.

  1. Remove eyeglasses.
  2. Rub your hands together to warm and relax them.
  3. Gently and softly, place your left palm over your left eye, your right palm over your right eye. The fingers of your hands may overlap on your forehead.
  4. Adjust your hands so that no light enters your eyes.
  5. Close your eyes.
  6. Imagine that the room is dark, the building is dark, and in fact, it is nighttime and dark everywhere. Pretend you are looking far ahead into endless dark space.
  7. When you are ready to re-enter the world, slowly remove your hands from your eyes. Gradually open your eyes. Are your eyes relaxed? Is your gaze softer than before? How is your mood? Can you smile easily?


Several such relaxation exercises can be found in Paul Linden's book, Comfort at Your Computer.

Watch for More Tips

Future articles in this series will share more ideas for healthy, comfortable computer use.

Resources

www.doctorergo.com—Dr. James Sheedy's Web site about computer vision syndrome

Comfort at Your Computer—This book, by Paul Linden, Ph.D., is a rich resource for all computer workers.

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