Desks for Comfortable Computer
Monitor, Keyboard and Mouse Must Be Positioned for
Prolonged usage of computer results in
eyestrain and stress on neck, shoulders, wrists and
arms. These can be alleviated through proper design and
modifications of the desk.
In terms of proper design, otherwise
known as ergonomic design, we actually refer to the
healthy interaction of a person to his or her
surroundings, particularly furniture and machinery.
Should a computer monitor be
ergonomically designed, its height should maintain its
user head to be straight and not tilted up or down which
results in neck strain. The eye level should be 5 to
7.5cm (2 to 3 inches) below the top of the monitor
University’s Human Factors and Ergonomics Research Group
advises that when a person holds an arm out
horizontally, the fingertips should touch the center of
the screen. (See point 2 on the attached diagram from
This arm reach also places the screen at the best
distance (point 4).
Display holders for flat screens are
easier to adjust than holders for bulky CRT displays.
Documents should also be placed where
they cause little movement of the head:
Between the screen and keyboard (6);
To one side at screen height on a
document holder attached to the display; or
On a holder standing beside the monitor
and angled slightly towards the user
Keyboard and Mouse
The keyboard tray should be about 3/4 to
1 1/4 inch (2 to 3 cm) below elbow height so the user
can type with forearms at an angle greater than 90
degrees to the upper arms (7, 8). This helps to prevent
compression of nerves at the elbows.
The tray should slide or swivel out for
the person to use the keyboard without having to reach,
so that upper arms are upright and relaxed at the side
of the body. This avoids strain on shoulder muscles.
To keep the wrists straight in line with
the forearms, the tray should be tilted (10) so the back
is lower than the front (a negative tilt). Flexure of
the wrists can cause inflammation of the nerves to the
hand (carpal tunnel syndrome).
Low-cost keyboard trays can be attached
under a desk surface so they pull out on drawer glides.
A tray on an articulating arm is better since it can be
set for tilt and height.
The keyboard should center the letter
keys, not including the pad of number keys to the right
of a full-size keyboard, in front of the user (9).
The mouse should also be positioned so it
can be used with arm and shoulder relaxed, without
reaching. Research at Cornell has shown the best
position for a mouse for right-handed people is over the
number pad. Some keyboard holders have mouse trays that
can be swiveled over the number keys. In another type,
the tray slides to left or right.
Also in the Cornell
diagram: 3 refers to avoiding
should place feet flat on floor or a foot rest; 11,
worksurface and keyboard tray should be stable (no
Cornell advises people to take frequent
The space under the desk must be free of
obstructions to feet such as trash cans, boxes and
files, which can cause a person to move the chair away
from the desk and lean forward, defeating the purpose of
For anyone using a computer frequently
for more than one hour at a stretch, the positioning of
monitor, keyboard, mouse and documents makes the
difference between comfort and the pain that comes from
strained muscles and joints.
This article has been
with the kind permission of Mr. Thomas Kelly. For more
information, please feel free to visit the website.