Computer Vision Syndrome


Computer Vision Syndrome (CVS) is the general term used to describe a variety of vision-related symptoms that may be caused or aggravated by regular use of a computer for two or more hours a day. 

These symptoms, which were identified by optometrists in a nationwide survey, include: temporary myopia (nearsightedness), eyestrain, headaches, blurred vision, dry or irritated eyes, neck and back aches, increased sensitivity to light, double vision and after-images. 

The same survey uncovered four environmental factors that have the most impact on whether or not a computer user will develop CVS. These factors are: 

• the arrangement of the office; 

• poor lighting; 

• screen resolution; 

• screen glare. 
 
 

THE MAGNITUDE OF THE PROBLEM

In 1991, James Sheedy, O.D., Ph.D., chief of the VDT Eye Clinic at the University of California, Berkeley, conducted a nationwide survey of optometrists. Sponsored by Optical Coating Laboratory, Inc., manufacturer of GlareGuard® anti-glare filters, the survey sought to determine how many patients had eye problems caused by computer use, the most prevalent symptoms, diagnoses and treatment. 

Respondents indicated that, on average, 14.25 percent of their patients -- or nearly 10 million people annually -- complain about symptoms primarily associated with computer use. The optometrists further reported that conventional treatment, such as prescription lenses or spectacle design changes, alleviated only a portion of the problem, the remaining symptoms being directly related to the computer work environment. 

ARE YOU AT RISK FOR CVS?

To determine whether you are at risk for CVS, answer "yes" or "no" to the following statements: 
 
 
Yes No  
    The middle of the computer screen is about 20 degrees below eye level. 
    If hard copy needs to be keyed into the computer, it is located about the same distance from the eye as the screen is. 
    Any windows are at right angles to the screen, rather than behind or in front of it. 
    There is enough light to read hard copy without straining. 
    Screen reflections from overhead or desk lights are non-existent.
    Contrast is adequate to produce sharply defined images on the screen.

If you answered "no" to one or more of the above, you could be a candidate for computer vision syndrome. The greater the number of "no" responses, the more likely you are to develop CVS symptoms. 
 
 

WHAT CAN BE DONE TO MINIMIZE CVS?

Luckily, computer vision syndrome, once recognized, is fairly easy to correct. To begin, anyone who suspects CVS, or who works at a computer several hours a day, should have a thorough eye exam. Make sure your optometrist or ophthalmologist knows that you use a computer regularly. He or she may prescribe special glasses and/or an anti- glare screen filter, as well as make other ergonomic recommendations. 

If your doctor is not an ergonomics expert, you should consider making certain office modifications on your own. Review any "no" answers to the CVS risk assessment, above, and take steps to correct the situation. 

Try to place your computer at right angles to any windows. If this is not possible, put blinds on the windows or erect outside awnings to reduce direct sunlight. 

Install a screen or partition behind your computer to reduce both outside light and overhead glare. Use non-reflective paint or coverings on the walls facing the computer. 

Use equipment with brightness controls or add such controls to your screen. If possible, relocate lamps that cause reflections on the screen; add dimmer switches to overhead lights or use coverings on fluorescent lights. At the same time, make sure there is sufficient light to read hard copy without straining. 

Adjust the height of your desk or chair so the middle of the computer screen is about 20 degrees below eye level. The screen itself should be 16-30 inches from your eyes. Use a stand for hard copy so that source documents and the computer screen are at roughly equal distance from the eyes. 

Finally, install an anti-glare, optically coated glass filter. Underscoring the value of this step, the American Optometric Association (AOA) granted its first Seal of Acceptance for any vision care product to GlareGuard. The high resolution, high contrast filter increases viewability dramatically -- a major contribution in the fight against CVS. 
 
 

IN CONCLUSION

Computer vision syndrome affects mental and physical well-being and impacts productivity. Unlike many other work-related situations that affect health, however, CVS can be virtually eliminated by taking a few simple, inexpensive precautions. With over 50 million American workers using computers daily, such steps are well worth it.