Computer World. Матросова Т.А. - 81 стр.

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More recent controversy surrounds very low frequency (VLF) and extremely
low frequency (ELF) electromagnetic radiation produced by video displays’
horizontal and vertical deflection circuits, respectively. Researchers have reported a
number of ways that electromagnetic fields can affect biological functions, including
changes in hormone levels, alterations in binding of ions to cell membranes, and
modification of biochemical processes inside the cell. It is not clear, however,
whether these biological effects translate into health effects.
Several epidemiological studies have found a correlation between VDT use and
adverse pregnancy outcomes, whereas other studies found no effect. The most recent
analysis, published this year found no increased risk of spontaneous abortions
associated with VDT use and exposure to electromagnetic fields in a survey of 2,430
telephone operators. This study, which measured actual electromagnetic field strength
rather than relying on retrospective estimates, seems the most trustworthy to date.
The authors note, however, that they surveyed only women between 18 and 33 years
of age and did not address physical or psychological stress factors.
A 1990 Macworld article by noted industry critic, Paul Brodeur, proposed that
users maintain the following distances to minimize VLF and ELF exposure:
• 28 inches or more from the video screen
• 48 inches or more from the sides and backs of any VDTs.
Although these guidelines seem overly cautious, a fundamental principle is that
magnetic field strength diminishes rapidly with distance. Users could, for example,
select fonts with larger point sizes to permit working farther from the screen.
Remember that magnetic fields penetrate walls.
Over-reaction to ELF and VLF radiation can also compromise ergonomics. In a
campus computer lab, for example, all displays and keyboards were angled thirty
degrees from the front of desktops to reduce the radiation exposure of students behind
the machines. The risks of poor working posture in this case appear to be greater than
the radiation risks.
A final form of radiation, static electric, can cause discomfort by bombarding
the user with ions that attract dust particles, leading to eye and skin irritations. Anti-
static pads, increasing humidity, and grounded glare screens are effective remedies
for these symptoms.
Avoiding carpal tunnel syndrome: A guide for computer keyboard users
Carpal tunnel syndrome (CTS) is a painful, debilitating condition. It involves the
median nerve and /the flexor tendons that extend from the forearm into the hand
through a “tunnel” made up of the wrist /bones, or carpals, and the transverse carpal
ligament. As you move your hand and fingers, the flexor tendons rub against the
sides of the tunnel. This rubbing can cause irritation of the tendons, causing them to
swell. When the tendons swell they apply pressure to the median nerve. The result
can be tingling, numbness, and eventually debilitating pain.
CTS affects workers in many fields. It is common among draftsmen,
meatcutters, secretaries, musicians, assembly-line workers, computer users,
automotive repair workers, and many others. CTS can be treated with steroids, anti-

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