by Thomas Hartmann

Thomas Hartmann is a contributing editor at Popular Computing. He is vice-president of Langley-St. Clair Instrumentation Systems, a safety peripherals firm.

How Dangerous?

Can your home or office computer make you sterile? Can it strike you blind or dumb?
    The answer is: probably not. Nevertheless, reports of side effects relating to computer use should be examined, especially in the area of birth defects, eye complaints and postural difficulties. Although little conclusive evidence exists to establish a causal link between computer use and problems of this sort, the circumstantial evidence can be disturbing.

Birth Defects
Several reports pertaining to birth defects deserve our attention. One of these deals with Laura Moore, who worked on a computer terminal at the telephone company's Renton (Washington) office outside Seattle and who throughout her pregnancy avoided drugs (even aspirin), cigarettes, coffee and alcohol. Although two of her co-workers had had problem pregnancies, Laura was sure she'd have no difficulty. But on January 14, 1982, her son Brandon was born with a massive spina bifida, his spinal cord uncovered and protruding from the back.
    Other reports issue from Air Canada in Montreal, where seven out of thirteen pregnancies among computer terminal operators resulted in spontaneous abortions; from the Toronto Star, where four of seven births to terminal operators resulted in birth defects; and from a Sears Roebuck terminal center in Dallas, Texas, where there were eight spontaneous abortions out of twelve pregnancies over a thirteen-month period in 1979-80. In addition, of twelve pregnancies among terminal operators for the Defense Logistics Agency in Marietta, Georgia, seven were miscarriages, two were normal births and, as the U.S. Army concluded following its own study, there were "three cases of congenital malformation, representing an unusual statistical event for which no explanation could be found."
    In response to these "pregnancy problem clusters," which have shown up in several other areas beyond those listed here, the National Institute for Occupational Safety and Health (NIOSH) has undertaken a massive study of six thousand pregnancies. Dr. Michael Rosenberg, chief of reproductive health activity at NIOSH, hopes the investigation will bring about some conclusive findings: "If the results are negative, this study will effectively put the question to rest. If the results are positive that computers are causing birth defects, the study will allow us to accurately measure the degree of risk."

Eye Complaints
Pregnancy problems represent only the smallest percentage of complaints from operators of computer terminals, or VDTs (video display terminals). Eye fatigue, watering or burning eyes, cataracts, failing eyesight and a host of other complaints are epidemic. Recently a task force of the Canadian government went so far as to recommend that workers be required to spend no more than five hours per day on terminals and that pregnant women avoid them altogether.
    One area of great concern involves the x-rays produced by computer terminals and home computers' cathode ray tubes, or CRTs, which operate in the same manner as your television picture tube. Accelerated to a very high velocity by the application of a high voltage (on the order of 10,000 to 25,000 volts), a beam of electrons scans the face of the tube. When it strikes the atoms of phosphor that coat the inside, the outer electrons are torn off, causing the atoms to become ionized and to produce radiation, including light, ultraviolet rays and x-rays.
    To meet government standards for radiation emission, most manufacturers of picture tubes now use lead-impregnated glass for the envelope of their CRTs to absorb most stray radiation. Nonetheless, if driven hard enough, CRTs will produce measurable levels of x-ray.
    In a recent letter to Byte magazine, the U.S. Food and Drug Administration stated that after subjecting various computer terminals to abuse, its inspectors were unable to detect any x-radiation from the terminals. Inconsistent with its usual insistence on scientific accuracy (but perhaps consistent with its concern about bad press), the FDA neglected to say what sorts of terminals were tested, whether they were high-resolution (using higher voltages) or low-resolution, monochrome or color, and whether there were any scientific controls on the study.
    In fact, in another 1978 study, not referred to in its letter and now "out of print" (Evaluation of Radiation, FDA #81-8153), the FDA tested 125 monitors and found that 10 of them emitted high levels of x-radiation when the line voltage (from the plug in the wall, usually 120 volts) was raised to 130 volts. This increase of the line voltage is known as a "stress test" and is designed to make machines show up potential problems. Eight of the machines were well in excess of the FDA's own standard for radiation, which was first developed for black-and-white TV viewing.
    Fortunately, most terminals emit so little x-radiation that it is well within the range of naturally occurring background radiation. But we must keep in mind that exceptions do exist. Summarizing the x-ray issue, the Ontario Public Service Employees Union concluded in its informative booklet The Hazards of VDTs (1901 Yonge St., Toronto, Ontario, M4S, $2):

While these various testing agencies seem satisfied that X-radiation emissions from VDTs pose no significant hazard to operators, a number of things must be considered.
1. VDTs do leak X-radiation. The controversy is over what level of radiation is harmful.
2. X-radiation emissions have been measured separately, without considering possible combined effects with other forms of radiation being emitted....
3. Recent studies on the health effects of low-level radiation force us to assume there is no known safe level for radiation exposure.

    Although much has been written on the VDT safety issue, according to a recent "definitive" study by the National Academy of Sciences the subject is far from closed. Adding to the confusion are bills introduced by several state legislatures demanding various means of protecting workers from computer terminals. In addition, the National Union of Working Women (also known as "9-5") has instituted a petition drive calling for, among other things, radiation shielding for computer terminals; such shielding has spawned a small industry of its own, with lead-impregnated acrylic screen shields being sold by at least three companies in the United States and by a half-dozen firms in Canada.

Other Radiation
Particularly at the seashore or on the ski slopes, where sunlight is more directly reflected into a person's face, ultraviolet (UV) light has long been known as one of the major culprits behind burning, watering eyes. Now similar symptoms are being widely reported among VDT operators, and some authorities believe that UV radiation from terminals can have a damaging effect on the human eye that might even lead to blindness.
    When two copy editors at the New York Times developed cataracts after working on VDTs for six and twelve months, respectively, Dr. Milton Zaret, associate clinical professor of ophthalmology at New York University, testified that in his opinion the cataracts had been caused by radiation, probably microwaves, from the terminals. Tests by the U.S. government, however, found microwave radiation from the Times' terminals to be within acceptable limits. (Acceptable U.S. levels for microwave radiation are 1,000 times higher than, for example, Soviet standards; the former recognizes only heat-caused damage induced by microwaves, whereas the Soviets claim there are other far more subtle and equally damaging consequences from microwave exposure.)
    Since that time, numerous other cases of VDT-related cataracts have been recorded. These are detailed in the Cold Type Organizing Committee's report Don't Sit Too Close to the TV: VDTs/CRTs and Radiation (Box 40, Jerome Ave. Station, Bronx, NY 10468; $1), one of the most complete summaries of the computer safety controversy.

Posture Problems
Two of the physicians I asked to comment on birth defects in connection with computer use suspected that difficulties could arise from improper posture. Both preferred to remain anonymous because of the speculative nature of their comments.
    "If you take a young squash from the vine and put it in a plastic milk bottle, it will grow to assume the exact shape of the bottle," said one doctor by way of explanation. "Similarly, sitting hunched over in a chair for eight hours a day can cause pressure on the womb or on the aorta, which supplies blood to the womb, or on some of the veins that drain it back off, and this may conceivably be responsible for the sorts of birth defects we're seeing described here."
    Even without the specter of birth defects, poor posture can cause fatigue, headaches and general discomfort. Because a computer user's concentration is directed at the screen rather than at a variety of stimuli, there is a tendency to sit in a fixed position for long periods of time. The human body's musculature and bone structure, especially in the back, were simply not designed for such stress. Frequent breaks, simple stretching and computer placement at a comfortable height can do much to dispel such complaints.

An Obsolescent Problem
The technology that created the computer safety issue is on the verge of providing a solution. The greatest source of danger could be eliminated by an inexpensive low-voltage computer display to replace the high-voltage CRT. Although the quest for such a replacement has been going on for years, only recently have two promising display techniques emerged from the laboratories to appear on production lines.
    Mighty IBM has staked its reputation on a "gas plasma" flat-panel display that employs low-voltage ionized gases instead of a high-voltage electron beam to generate its orange-colored image. This display, which may be standard on many terminals in the next ten years, should have none of the attendant radiation problems associated with present CRT technology.
    At the same time, Japanese manufacturers and American marketers have introduced a panoply of portable computers with black-on-gray liquid-crystal displays (LCDs) similar to those used on digital watches, which also produce no radiation. The Epson QX-20 led the way with a four-line display, soon improved upon by the Radio Shack Model 100's eight lines of text and followed by models with larger screens and greater resolution. If problems of fragility and cost can be conquered, these displays could become standard on many home computers.
    The back strain and postural problems associated with computer use are also receiving attention from manufacturers. New display screens with non-glare surfaces tilt and swivel and adjust to different heights so that computer users can adapt to the new workplace environment. Additionally, a whole new generation of office furniture designed to match humans to computers, in the most comfortable manner possible, is helping to allay many concerns and complaints. Home computer users may not have access to all these fancy enhancements, but rarely do they spend forty hours a week at their machines.
    As computer terminals become more and more sophisticated, the risks associated with them may pass away altogether. On the other hand, since millions of old-style CRTs will most likely remain in the workplace and in the home, the debate on computer safety will no doubt continue for some time to come.

There are several specific steps you can take to help reduce the problems and concerns arising from home computer use.
• In general, it's a good idea to sit as far away from your computer screen as comfort allows. Detachable keyboards are making it easier to follow this advice from the experts, some of whom recommend a distance at least three times as great as the screen's diagonal measurement.
Children using television screens should be especially careful. Doctors at the Veterans Administration Medical Center in Washington, D.C., recently warned that pre-1970 television sets serving as monitors with home computers could be exposing users to nearly nine times the maximum recommended dosage of radiation.
• For an extra margin of safety, consider attaching a leaded acrylic screen shield to your monitor to block both x-rays and ultraviolet radiation. Such shields often have non-glare surfaces that enhance eye comfort by diffusing extraneous light reflected by the screen. A non-glare surface can also be added to your screen with a simple adhesive-backed plastic sheet available at Radio Shack and other computer stores.
• Arrange your computer work area so that the keyboard is clearly illuminated while the light is directed away from the display screen. The greater the contrast between the characters on the screen and the overall light level, the easier the effect on your eyes. Of late, computer makers and owners have been switching from green- to amber-tinted monitors, following findings by the West German standards bureau that amber is more relaxing on the eyes.
• Sit in a chair that supports your lower back and promotes proper posture. Adjust the height of the chair so your hands rest comfortably on the keyboard and the screen is at eye level. Also, arrange your work area so you can easily read the documents being entered into your word processing program or the instructions for that complex piece of software you're trying to master.
• Every thirty minutes or so, take a break from your computer to stretch and walk around. You can also exercise your eyes by focusing on objects at different distances from you; this prevents the weakening of eye muscles that can result if you focus on the computer screen surface for long periods.


Return to Table of Contents | Previous Article | Next Article