Computer Vision
Today, the computer has become an important part of many businesses, agencies and homes. From publishing reports to statistical analysis, what once took hours and days to perform is now able to be done in a fraction of that time due to advances in the computer field. However, with all of the interest in the computer's accomplishments, surprisingly little interest has been shown in the operator of the computer.
For years, the number of complaints of computer related eyestrain, backaches, headaches, and muscle fatigue have been increasing. What has not increased is the authoritative information on their causes and how to reduce or alleviate these problems. My hope is that I can provide some basic information and advice to reduce the strain and stress on the computer user.
There are three main components of the computer. The first is the CPU, or central processing unit. This is the "brains" of the computer, and is the component that the user has the least amount of interaction with. The second component is the keyboard. It is similar to the keyboard of a typewriter, and is used to enter information onto the screen. The final component is the computer screen, or monitor, which is really a small television and is therefore termed a "self-illuminating object". That is, unlike paper, which is seen by reflection of light, it, in and of itself, is a source of light. Many of the visual problems associated with the user of the computer is related to this "self-illuminating" environment.
Since the keyboard and screen are the two main components that the user is dealing with, we will discuss them separately.
In order to reduce strain, the keyboard should be placed directly in front of the user, and at elbow height with the arms relaxed. This insures that the wrists are not bent when typing. Bending of the wrist while using the keyboard can cause severe muscle spasms, inflammation, and even permanent damage. A "wrist rest" should be placed in front of the keyboard. A wrist rest is a cushion on which the heel of the hand rests, not the wrist. This will act as a support for the hand, wrist, and the arm of the user, reducing the likelihood of further muscle strain.
Since it is easier for the eyes to look downward than straight ahead or upward, the computer screen should be placed below straight ahead sight. Further, the screen should be aimed at the face of the user. If this results in too much reflection from the surrounding room lights, it may be tilted slightly so that it is aimed at the chin or chest. A filter is advised to be placed over the screen to further reduce glare and reflection and to enhance contrast. The recommended filter is a 3M Circular Polarizing Filter. This type of filter is by far the best.
A word about screen colors is in order. The color combination on newer screens that causes the least amount of eyestrain and reflected glare is black letters on a white background. This allows for the fastest recognition of letters without causing eye sensitivity that may occur when certain other colors are used. This may not be the most popular combination, but it is now considered to be the best. The only exception to this is when the individual has such eye conditions as cataract or macular degeneration. In these situations, a reverse screen, white letters on a black background, is recommended.
Since the computer screen is a self-illuminating object, as mentioned earlier, it is important that the brightness of the screen is set to a comfortable and proper level. If the brightness is set too high, glare and reflection will increase while readability of the letters decreases. If the brightness is set too low, the contrast is reduced and clarity of the letters will suffer.
In many cases the lighting in the office where the computer is being used is over twice that which is necessary to do the work. The simplest way to reduce the lighting is to remove two bulbs from the four bulb fluorescent ceiling fixture. This not only reduces the brightness in the room but will reduce the appearance of sources of glare and reflection as well. If this reduces the lighting too much to allow papers and desk objects to be seen comfortably, a non-fluorescent desk light should be used to provide the additional light. Another, a perhaps better, solution is to have dimmer switches connected to the fluorescent lights. These are made by a company called Lutron and allows the individual to determine the lighting that he or she feels most comfortable with.
Windows should be to the side of the computer screen, not in front of or behind it. The blinds or curtains over the windows should be closed when the computer is being used. Again, light from the windows is a source of glare and reflection. Any reduction in this "extra" light in the room will allow for greater ease in using the computer.
For those individuals wearing glasses, special coatings and lens designs are now available specifically for the computer user. These coating have been shown to not only reduce the amount of glare and reflection from the computer area, but will also reduce the sensitivity of the user to certain computer generated wavelengths of light. New lens designs have also been introduced that reduce the amount of strain on the eyes when they view the computer.
A concluding word about computer generated radiation is needed. The National Institute of Occupational Safety and Health (NIOSH) as well as other health related organizations have conducted numerous experiments and testing to determine X-ray, ultraviolet ray, infrared ray, and microwave transmission from the computer as well as operator exposure. The conclusion was that the computer user is not exposed to any more radiation while sitting in front of a computer than he or she would be anywhere else in the environment. As always, continual testing is being done regarding radiation as well as other environmental hazards.
Please feel free to call our office should you have any computer related questions that we have not covered here. With Dr. Glasser a nationally recognized authority on computer vision, we'll be happy to help with any concerns that you have.
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