Computers & Vision
Also see Computer Continuum, Kid’s and Computers
and Computer Cubicle!
Ergonomics is the science that seeks to adapt work or working conditions to suit the worker. Ergonomic information regarding vision and computers. More people are working with computers than ever before. Because of this trend toward greater computer usage and the resulting demands on the operator’s vision, we have completed a study of the current literature concerning this type of work, which we would like to share with you.
The chief physical complaint of people working with computers is visual strain and fatigue. Studies show that 47% of computer workers have eyestrain, within three hours of initiating their work. One cause of discomfort and inefficiency is GLARE. Glare may be defined as “something in the line of sight that is significantly brighter than the surroundings.” The computer display screen acts like a mirror, reflecting light or bright colors. It is wise to have curtains over windows, and dark, or flat (matte) painted walls. Also, the operator should refrain from wearing white or light colored clothing. Other means of reducing glare are: utilizing an anti-reflective screen on the monitor; changing the angle of the screen by tilting it horizontally or vertically; or moving your station to a different position. If your desk is of a shiny laminate material, use a matte-finished desk blotter to degrade the reflective quality. A good test to determine whether glare is a problem is to place a 12″ X 12″ mirror over the screen, keyboard and desk. Sit in your normal position; if you see any of the light or bright sources in the mirror, you are actually demonstrating glare. Try to eliminate or reduce it.
Proper LIGHTING in the office is very important. Prior to computers, it was recommended that a general office have about 1,000 lux of light. With the use of computers, however, that figure was reduced to 300-500 lux. The prime reason for this reduction in the amount of light is that a sharp contrast between the monitor and the background is a major source of visual discomfort. You may benefit from task lighting, where copy work is illuminated by auxiliary lighting.
The MONITOR unit itself must be considered. Make sure that your computer monitor does not have a “ghost” image on the screen, which indicates a problem with phosphene absorption. There is much controversy if the radiation emitted from the monitor (front and sides) is harmful. Because that information could be found to be true in 20 years, we recommend that you have a UV400 (ultraviolet protection) filter included in your computer glasses. This would offer you some protection if 2 hours per day, 5 days per week, 50 weeks per year, and 10 years’ worth of exposure does prove to be damaging to your eyes or general health.
Another source of visual distress is the FLICKER in your peripheral field of vision from other monitors. If that is a factor, try to shield these from your peripheral field of view. There should be as much flexibility as possible in the placing of computer components so that they can be adjusted to each operator’s specific needs. If the screen has a swim to it (movement of the display), it is best to change to a better monitor. It is most important that the images on the video screen are clear.
The average visual WORKING DISTANCE for people using computers is 20 inches. If all your material–copy, keyboard, screen– are at the same distance of 20 inches, the fatigue factor will be decreased, because there will be less varying focusing demand on your eyes. It is also important to take breaks about five minutes each hour. This benefits your body and your mind, as well as your eyes. Look out a window at a distant object or view, or vary your task to another office duty for a while. Visual comfort and efficiency are interrelated; it is to your employer’s benefit to have you as visually comfortable as possible. Computer work demands a very high standard of vision. Because there is such a great demand on your eyes, there is always the potential of eyestrain.
Typically, in years past, eye care for a person without a specific complaint was non-existent. Today PREVENTIVE HEALTH CARE INCLUDES VISUAL CARE, and is becoming more informative in defining what can be done to prevent certain problems. One study revealed that there was temporary reduction of vision after three hours of computer work. The patients in the study went from 20/18 (actually better than 20/20) to about 20/25, after three hours at the computer. After they stopped their work, it took about 16 minutes to recover their original 20/18 level. It is not unusual for computer operators to have difficulty in making a visual shift from near to far and from far to near. This complaint may be a predecessor of nearsightedness, of an increasing amount of nearsightedness, or presbyopia, a condition that is improved by the use of reading glasses.
Studies show that with extensive use of computer monitors, people under the age of forty tended to INCREASE IN THE NEED FOR READING GLASSES.
Many times this new environment makes it necessary for operators 35 + to get special glasses for near, usually in bifocal form. Bifocals are usually in the lower half of the lens, so that one can read on his desk, lap, etc at 16″. Since the computer monitor is straight ahead, at eye level at 20″, it is possible for the operator to view the screen through the typical bifocal only if he tips his head back and moves closer—a position that quickly becomes tiring and creates a pain in the neck. Fortunately, there are ways of resolving this problem, SPECIALLY DESIGNED, SPECIAL-PURPOSE LENSES.
May be used as a peripheral to your computer—a very specific component to your computer, and your link with it through your eyes. Wider bifocals can be designed to fit very high, this would work well at the computer monitor, but would not be appropriate for general purposes or walking. Specially designed single-vision lenses, focused for the computer world of about 20 inches, give another alternative that works well, as do very high-fitting half-eyes. Some new invisible progressive multi-focal lenses are specially designed for computers; Technica or Readables may be the answer for you. Occasionally, tints are appropriate, to cut down glare or flicker. For the office environment, a light-pink tint is the best choice. Let us draw a parallel between the COMPUTER OPERATOR AND A MARATHON RUNNER.
The runner must stretch, exercise, and train, in order to perform at his highest physical level. He must also have the appropriate shoes for long-distance running. The computer operator must also be well prepared with, in his case, a very high level of visual skills. The visual skills are the focusing ability, the ability to make the eyes fuse together easily, and eye-tracking and eye movement skills. Developing these skills would be like the runner developing his body. Appropriate glasses for the computer operator’s near visual needs could be likened to the best possible running shoes for the marathon runner, since both help prevent problems from such demanding tasks.
It is important that your EYES BE CHECKED FOR NEAR VISUAL NEEDS, as well as for distance vision, for these are two different visual-functioning situations. Some studies show that, because of evolution from our being outdoor people to becoming very near-oriented people, nearsightedness has increased from 12% to 70%, in the past eighty years. The higher the visual demand, the more imperative it is to have more frequent care.
The most common complaints of computer operators, regarding their vision, include: rubbing eyes; headache, blurring of vision at both the near and far viewing distances, itching and burning eyes, eye fatigue, flickering sensations, losing place, increasing errors with reduced visual efficiency, and double vision. Most computers have a six-month service warranty and maintenance program.
WHAT IS THE MAINTENANCE PROGRAM FOR YOUR EYES?
BLINKING: Blinking is the windshield wiper of your eye and one of its purposes is to evenly and regularly spread tears over your eyes to keep them wet, seeing clearly, and healthy. Computer operators have been found to blink only 3 times per minute rather than the normal 15 times per minute. Contact lens wearers also can adopt an abnormal blink rate and pattern. Please be aware of this and enhance your blink pattern, rate, and ask for our fact sheet on blinking if needed.
View a related article: “Tips for Getting Relief”