Page 281 - Encyclopedia of Business and Finance

eobf_E 7/5/06 3:00 PM Page 258

Ergonomics

• Poor posture used with an incorrect seating height large enough for easy reading of screen character sizes with
a screen refresh rate fast enough to avoid a visible flicker.
• A monitor incorrectly positioned, resulting in eye
strain and vision problems An individual can experience blurred vision or fatigue
from a poor monitor viewing angle, reflected glare, or a
• Inappropriate lighting, causing glare on monitors low-quality monitor. Because glands in the eyelids pro-
and other work surfaces
duce tears that cleanse eyes as the eyelids blink and the
• High concentration, causing infrequent breaks eyes move, irritated eyes can develop because one’s blink
Guidelines for working conditions when using a rate tends to decrease when one is concentrating.
computer include: To avoid neck and eyestrain, an individual should:
Chair: A well-designed chair with easy-to-implement
• Use a copyholder positioned near the monitor to
adjustability is essential. A user can vary angles of back support material used with computer work.
support and the seat pan to control the degree of pressure
on the thighs and back. Weight should be evenly distrib- • Use lower levels of lighting to reduce glare on moni-
uted, with no extreme pressure points. An upright posture tors. Many older offices have high illumination lev-
is a little easier to achieve if the seat pan is tilted slightly els that are necessary for paper-intensive tasks—but
forward of horizontal. When a person is seated, feet are too highly lighted for computer work. Softer
should rest on the floor and the chair seat pan should be overall, or ambient, lighting should be used, with
even with the back of the knee, ranging from 13 to 19 task lighting added to surfaces as needed for more
inches above the floor depending on an individual’s illumination.
height. A foot rest may be used to relieve pressure on the • Relax eye muscles by shifting focus from the com-
thighs. Both lumbar and mid-level back support are puter screen to distant objects for a few seconds
needed. Arm rests, adjustable for height, are helpful to every 5 to 10 minutes.
many people. The chair should have a five-point base for • Take microbreaks to stretch the neck, shoulders,
stability and casters for easy movement.
hands, wrists, back, and legs as well as to rest the
Keyboard: The keyboard provides the primary means
eyes. Stretching exercises can be simple neck rota-
of interacting with a computer. The keyboard should be in
tions, shoulder shrugs, fists clenched and then
a comfortable position, and wrists should float over the
released, or arms hanging down naturally for a few
keyboard when keying with a light touch so wrists and
moments. Get up and move around about every 30
forearms remain straight. Although wrist pads are helpful minutes. Take a brisk walk if possible. Exercises with
for resting when not keying, they can actually create prob- hand weights will help with stretching and will give
lems when a user keeps wrists on them when keying the body isometric exercise.
because the wrists can bend down. Different opinions
exist on the appropriate angle of the keyboard; some peo- While it may be ideal to have individually adjustable
ple prefer a flat position while others find a reverse incline temperature controls, this is not feasible in many work sit-
more comfortable. Split and curved keyboards are avail- uations. For business offices, most people are comfortable
able, too. However, the most important part of keyboard with temperature levels at 68° to 72° in the winter and 72°
use is keeping the wrists straight in line with the forearm to 76° in the summer. Humidity levels should be main-
and not bent to the side. When voice-recognition technol- tained between 40 to 60 percent not only for comfort but
ogy becomes commonly used, dependency on the key- also for proper functioning of office equipment. Indoor
board will be reduced. air quality involves more than heating and cooling—air
Mouse: A mouse should be positioned next to the should be cleansed of pollutants (bacteria, dust, fumes,
keyboard, reachable without extending the arm in an awk- etc.), with fresh air added before circulation. Many factors
ward position. Again, a light touch is needed and users affect the efficiency of HVAC (heating, ventilation, and
should avoid gripping or squeezing the mouse. A wrist air conditioning) systems. These systems must be
support or adjustable mouse platform may be helpful if a designed for the number of people and the equipment to
user begins to develop wrist problems. A variety of shapes be used in each area because computers and other devices
are available for these pointing devices, and a trackball can can produce almost as much heat as a human body pro-
be used for the same purpose. duces.
Monitor: A monitor should be directly in front of the Another important concept is adjustability of work
user, with the top of the screen at or below the line of pace. Jobs may require redesign to allow workers to
sight, 18 to 30 inches away from the eyes, and tiltable to accomplish tasks at varying speeds or to enable workers to
avoid glare from overhead lighting and windows. If neces- rotate to different tasks or to use a variety of work meth-
sary, antiglare filters can be added. Screen size should be ods that permit different movements. Rest breaks are

258 ENCYCLOPEDIA OF BUSINESS AND FINANCE, SECOND EDITION