Information Technology Reference
In-Depth Information
into the air; others dispute the claim. Numerous studies on the impact of emissions from
display screens have also resulted in conflicting theories. Although some medical authorities
believe that long-term exposure can cause cancer, studies are not conclusive at this time. In
any case, many organizations are developing conservative and cautious policies.
Most computer manufacturers publish technical information on radiation emissions
from their CRT monitors, and many companies pay close attention to this information. San
Francisco was one of the first cities to propose a video display terminal (VDT) bill. The bill
requires companies with 15 or more employees who spend at least four hours a day working
with computer screens to give 15-minute breaks every two hours. In addition, adjustable
chairs and workstations are required if employees request them.
In addition to the possible health risks from radio-frequency exposure, cell phone use has
raised a safety issue—an increased risk of traffic accidents as vehicle operators become dis-
tracted by talking on their cell phones (or operating their laptop computers, car navigation
systems, or other computer devices) while driving. As a result, some states have made it illegal
to operate a cell phone while driving.
Carpal tunnel syndrome (CTS) is an aggravation of the pathway for the nerves that travel
through the wrist (carpal tunnel). CTS involves wrist pain, a feeling of tingling and numbness,
and difficulty grasping and holding objects. In the late 1990s, many worker compensation
claims were filed by people whose job required them to work at a keyboard many hours a
day. However, a 2001 study by the Mayo Clinic found that heavy computer users (up to
seven hours per day) had the same rate of carpal tunnel as the general population. It appears
that CTS is caused by factors other than the repetitive motion of typing on a keyboard.
72
Avoiding Health and Environmental Problems
Many computer-related health problems are caused by a poorly designed work environment.
The computer screen can be hard to read, with glare and poor contrast. Desks and chairs can
also be uncomfortable. Keyboards and computer screens might be fixed in place or difficult
to move. The hazardous activities associated with these unfavorable conditions are collectively
referred to as
work stressors.
Although these problems might not be of major concern to casual
users of computer systems, continued stressors such as repetitive motion, awkward posture,
and eye strain can cause more serious and long-term injuries. If nothing else, these problems
can severely limit productivity and performance.
Research has shown that
developing certain ergonomically
correct habits can reduce the risk of
adverse health effects when using a
computer.
(Source: Courtesy of Balt, Inc.)
The science of designing machines, products, and systems to maximize the safety, com-
fort, and efficiency of the people who use them, called
ergonomics
, has suggested some
approaches to reducing these health problems. The slope of the keyboard, the positioning
and design of display screens, and the placement and design of computer tables and chairs
have been carefully studied. Flexibility is a major component of ergonomics and an important
feature of computer devices. People come in many sizes, have differing preferences, and
require different positioning of equipment for best results. Some people, for example, want
to place the keyboard in their laps; others prefer it on a solid table. Because of these individual
ergonomics
The science of designing machines,
products, and systems to maximize
the safety, comfort, and efficiency of
the people who use them.
