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Computer Vision Syndrome

Symptoms of CVS

  • Tired, burning, itching eyes
  • Dry eyes or watery eyes or both
  • Headaches
  • Double vision and after- images
  • Sensitivity to light
  • Pain in the eyes
  • Development of excessive blinking or squinting

Eye-Opening News About Computer Vision Syndrome
Do you or your coworkers spend several hours a day in front of computer screens? If so, like more than nearly 15 million American computer users, you may be experiencing Computer Vision Syndrome (CVS).

According to NIOSH, nearly 80% of those working at a computer for more than two hours a day suffer from the symptoms of CVS. CVS is the most common repetitive stress injury brought about by video display terminal (VDT) work, despite the fact that it is not as well known as some other computer-related conditions such as carpal tunnel syndrome. But while less than one in four regular computer users suffer from carpal tunnel syndrome, three times as many experience CVS.

Why Prevent CVS?
Workers with computer-related vision problems are usually less efficient on the job and experience higher error rates as the day goes on. The Journal of the American Optometric Association reports that just a small amount of visual interference, such as glare, causes a reduction in employee efficiency of 4 to 19 percent. Poor contrast, poor resolution, glare and reflections on the screen can all exacerbate CVS symptoms.

The following problems are characteristic of working in front of computer screens. Even though OSHA's ergonomics standard has been rescinded, it still makes sense to prevent workplace injuries, so possible solutions are also provided.

Reflections from surrounding light sources. Glare from lights reflecting off the screen lowers the contrast, thus forcing the eyes to work harder.
Typical office lighting is twice as bright as the optimal lighting conditions for computer work. Workstation lighting should be shaded to avoid reflections on the monitor. Use a glare reduction filter approved by the American Optometric Association.

Unclear or flickering images on VDT screen.
Select monitors with higher hertz, or frequency. These have a lower amount of perceptible flickering. A monitor with a higher pixel (at least 110 pixels per inch) or dot count has better resolution and readability.

Continuous, uninterrupted activity at a computer station. This causes the eyes' focusing mechanism to tire.
Proper eyeglass prescriptions. Take frequent breaks-at least ten minutes every hour.

Focal Distance is farther than normal reading distance. People normally hold reading materials 12 to 18 inches from their eyes. Eye doctors typically prescribe reading or "near vision" prescriptions for that range, but computer screens are usually situated 20 to 26 inches from the user.
Move screen closer. Get a special lens prescription to focus clearly at these distances for extended periods.

Screen height. For wearers of bifocals and trifocals, the prescription for close tasks is set into the lower portion of the lens, but VDTs are set relatively high, near eye level or higher.
Bifocal and trifocal wearers may require special lenses to function effectively at computers. Adjust computer screens 10 to 20 degrees below eye level for these users

Source: Jesse Rosenthal, OD, MPH, and Mort Soroka, Ph.D., "Managed Vision Benefits," published by the International Foundation of Employee Benefit Plans.

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