|
|
Eyestrain and
using Computers
In recent years,
many of us have become avid computer users, both at home and in the office.
Many can suffer headaches, visual discomfort and general malaise if work
patterns and workstation design are inadequate. A set of internationally
recognised standards are in place to help us minimise problems related to
workstation design and these can be obtained from most good bookshops. The
following general advice is based on these standards.
The information contained here is based on
"the average person" - variations for individual comfort are perfectly
acceptable.
You should be comfortable at your work. If you experience pain or discomfort
you are unlikely to perform well.
Have your eyes examined regularly.
The distance you should sit from your screen depends on the size of the
characters you are using.The best readability of your screen is generally
considered to be when the characters are 21 minutes of arc. This means 3.7mm
characters on screen should be viewed at a distance of 60cm. If you sit too
close to the screen e.g. 50cm, you may experience eyestrain.
The top of your display screen should be on, or just below, eyelevel. This
means you should never have to look down more than 20 degrees to see the
centre of the screen. Near visual tasks are distinctly uncomfortable when
the downward viewing angle is greater than 60 degrees.
Eliminate reflections from the screen by angling the display unit, by moving
lights or by using a good quality anti-glare screen. Windows can be a source
of trouble if light casts a veiling glare across the screen. Move the screen
to a different location on your desk or within the room.
Adjust the display brightness and contrast - most users prefer high contrast
and low brightness.
Ensure the text or images you view are displayed at the best size and
resolution. Use the on-screen controls to improve readability.
Your keyboard should be positioned at a comfortable height and reach for
your build. Wrists should be supported on the desk or use a wrist rest.
Medical opinion states your wrists should not be flexed more than 10 degrees
above or below the horizontal, nor more than 10 degrees sideways. Your mouse
should be within comfortable reach.
For a typical workstation, your desk space area should be 160cm wide by 90cm
deep although this may vary a little for personal requirements. A fixed
desktop height is typically 72-75cm from the floor and there should be 6cm
space between the top of your thighs and the underside of the desk. The desk
surface should be non-reflective and all cables safely tidied.
Take frequent breaks from your workstation to stretch legs and arms.
Maintain head, neck and shoulder mobility by stretching.
Your vision may become blurred by persistent staring at any near task. You
should vary your focussing distance regularly to prevent the ciliary muscle
inside the eye from becoming "cramped". Look across the room or out the
window for a few seconds every 10 minutes.
Finally, if you have any doubts about your comfort and health when using
display screen equipment, do have it checked out.
|
|
|
