There are
several aspects of the computer task that make it especially
visually demanding and/or contribute directly to symptoms
for computer users. Mitigation of these problems can often
directly eliminate symptoms or reduce the demands of the
task so symptoms don't result from marginal visual
disorders. The most important visual environmental factors
are:
Lighting geometry and quantity
Glare from windows or overhead lights
Screen reflections
Computer display design - contrast polarity, resolution,
flicker, etc.
Work station arrangement
Office air quality
Workstation Arrangement
It is commonly recognized that "The
eyes lead the bodyTM". Since working at
the computer is a visually intensive task, our body will do
what is necessary to get the eyes in the most comfortable
position - often at the expense of good posture and
therefore causing musculoskeletal ailments such as sore neck
and back.
Viewing Distance
Probably the most common distance at which people view
reading material is 16 inches (40 cm)
from the eyes. This is the distance at which eye doctors
routinely perform near visual testing and for which most
bifocal or multifocal glasses are designed. Most commonly
the computer is located at a further distance from the eyes
- 20 to 28 inches (50 - 70 cm).
However, depending upon the task and the individual, other
working distances can also be comfortable.
