VDTs and vision
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Overview
Questions about the safety of the visual display terminal
(VDT) workstation, especially its effect on the human eye,
have increased since the introduction of the VDT nearly thirty
years ago. This information was written to inform vision care
professionals on technical issues related to visual discomfort
and to increase their awareness of environmental factors affecting
the visual system and proper usage of the VDT.
Introduction
A properly designed workstation is essential to an employee's
comfort, job satisfaction, motivation, and a sense of accomplishment.
This is particularly true of the visual display terminal that
plays such a prominent role in so many workstations. There
has been concern about the possibility of ill effects on the
display user's eyes, but there is no evidence that the human
eye is damaged by the light levels and visual tasks of a typical
office environment.
Working at a visual display is similar to working at any
other visually intensive task and may result in eye discomfort.
The eyes may become fatigued while performing intensive tasks,
however, this condition is temporary and is not harmful to
the eyes.
When VDT users complain about visual discomfort,
their concerns should be evaluated and treated on
an individual basis by
vision-care professionals.
Lighting, Reflection, and Glare
The display screen may reflect light from overhead lights, task
lights, light from windows, or clothing of a light color. The reflections
and the resultant glare can increase the difficulty of visual work.
The user's age should also be considered in problems of glare since
age affects eyesight in general, and glare sensitivity in particular.
Glare can usually be modified by lowering ambient
light, drawing window covers against bright light, wearing
less reflective garments, choosing more appropriate
task lighting, and cleaning the display screen. Keeping
the display screen clean, especially during conditions
of low humidity (e.g., in the winter with central heating),
is important as this decreases screen dust. Additionally,
neutral-density or micromesh filters may be helpful
in enhancing contrast or reducing glare.
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