This article is specifically concerned with issues that fall
under the province of ergonomics:
a broad, interdisciplinary applied science concerned
with optimizing the functionality of things people use,
and the tasks they perform,
so that the workplace is properly adapted to the worker.
This not only increases user comfort, but it also increases user
productivity as well, a double payback for your investment.
The primary approach to maximizing user comfort and productivity
with video displays is to continually optimize and improve
your work environment, your work habits and methods, and your equipment.
Not just when you setup a work area or room, or when you buy and install
the hardware and software, but every day and for every task.
All too often users accept a computer system as is, and are
afraid to adjust it or change it to suit their needs.
Other users are either too busy or just plain forget that their
display and work area need continuing attention.
The most crucial element of Video Ergonomics is the video display itself.
Obviously, if the display is not performing as it should then all of the
other elements discussed here cannot be effective either.
- The first step is to make sure that you match the display
to the intended application.
The most important factors include
screen size, image brightness, sharpness, and cost.
- Select the best video mode,
screen pixels and color-depth (number of screen colors), for your application.
- Carefully set up all of the display and video board controls for optimum image
and picture quality using DisplayMate.
- Regularly readjust the display controls when your application, room lighting,
screen resolution or color-depth change during the day.
- Clean the screen on a regular basis in order to keep the image as sharp
and as bright as possible.
- When the display no longer performs up to par, then either have it repaired
or buy a new monitor.
Setting Up Your Work Station
In this section we will summarize some of the most important issues
involved in setting up your work station.
A detailed discussion of the general work station and work environment is
beyond the scope of this article.
The screen size should be appropriate for the expected viewing
distance and the type of work.
For most users, a 15" to 17" diagonal screen should be satisfactory.
Larger screens are needed for graphics with multiple display windows.
Excessively small or large screens will increase eye fatigue.
The lighting for a VDT work area should be modified to maximize contrast
and minimize glare, while providing sufficient illumination for other
The display screens should be oriented perpendicular to windows
and other sources of glare. Blinds should be used to control
the amount of outside light entering the room through windows.
The optimum lighting level for VDT work is generally about 200 to 500
less than half of the standard office lighting levels of 750 to 1500
Use indirect lighting where possible.
Overhead lights should be recessed and baffled to reduce the possibility
of their entering into a user's field of view, or causing glare.
Uniformly balanced light levels are important in order to reduce eye fatigue
that results from continual iris adaptation.
If local task lighting is necessary,
a dimmer should be available to adjust the light level.
It is important to have an adequately sized work area,
and a work table that is large enough
for all necessary equipment and materials.
A functional layout is very important, with frequently used items
within easy reach.
Just about everything needs to be adjustable in order to properly accommodate
every user comfortably. Each user should frequently adjust his or her
work station in order to find the optimum configuration.
- To begin with, you need a comfortable chair that is adjustable in height
and has an adjustable and reclining backrest.
Casters and an armrest are important.
Adjust the chair first:
the user's feet should be flat on the floor;
if they're not, then use a footrest.
- The table height should be adjustable so that the keyboard is at
a comfortable height.
At the recommended height, your forearm should be nearly horizontal.
- The screen should be adjustable in height, position, and orientation.
Place the display so that it
is close to the straight ahead position where you will be sitting.
The top of the screen should be near eye level, so that you are looking
slightly downward, with an angle of roughly 20°
toward the center of the screen.
The tilt of the screen should be adjusted to help minimize glare.
Placing the display on top of the computer system unit,
which is itself on top of your desk,
as is often pictured in many advertisements,
is seldom an optimum position for a display.
- If you need a document holder for data entry, get one that is adjustable
in height, position, and orientation.
Set it up next to the display screen,
at a comparable height and distance,
so that you can easily switch your eyes between the document and the screen.
This will minimize eye accommodation fatigue due to a change in focal distance.
Many people don't realize that VDT work can create a good deal of job stress:
- Physical stress and musculoskeletal strain
arise from poor posture, poor quality chairs, poorly designed work areas,
as well as the static and sedentary nature of VDT work.
Change your seating position frequently and get up and stretch regularly.
- Psychological stress is the result of worker unhappiness.
Many studies have found that VDT complaints correlate with
general job dissatisfaction.
- General stress can arise from many factors including
a high work load, machine pacing, and electronic monitoring of workers.
This can be minimized by good job design, introducing flexibility
into the work pace and schedule, and frequent
rests in order to break the intensity of the VDT session.
In order to successfully minimize user eyestrain
it is necessary to deal with a wide variety of problems, any of which
may cause user eye discomfort.
Below, we bring together and summarize a number of issues
that are discussed throughout the DisplayMate Manual:
- Maintain a good general work environment.
- Proper lighting conditions are essential.
Pay particular attention to glare.
- Optimally position the display in your work area
so that you can face it without any unnecessary twisting and turning.
Regularly adjust its location and orientation
to suit your own varying work needs.
- Have a good quality display and maintain it in a state of good adjustment.
Clean the screen regularly.
- Regularly setup and adjust the display's controls
to suit your own varying needs,
in accordance with the room lighting
and the software's screen appearance.
- Use computer software that has been ergonomically designed for user
comfort and productivity.
This includes things like good screen layout and a logical and clear
presentation of information and requests for input.
- Regularly rest your eyes and take periodic work breaks
away from your work area.
To rest your eyes, close them for a while, look far away to change the focal
distance, and exercise the eye muscles by looking all around.
- Have regular eye exams with an ophthalmologist or optometrist.
A significant fraction of the population has improperly corrected vision,
so before beginning regular VDT work have an initial eye exam, and
tell the doctor that you will be working with a VDT.
If you wear glasses, make sure that the prescription is up to date.
Also consider getting a special pair of reading glasses with a
for the distances involved in video display work,
typically 20" to 26", which is about 8" further away than the distances used
for reading books and other printed material.
This becomes increasingly important after age 40.
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