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Preventing
Visual Discomfort
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at
the Computer
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Computer
workstations present complex visual needs. Challenges
can include uneven lighting, reflections and glare,
and prolonged use of the eyes. Here are some guidelines
to follow to reduce visual discomfort:
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Keep
lighting levels as even as possible.
To determine problem areas, shield bright sources
from your view with your hand or a file. If you feel
relief, eliminate the bright source. To improve lighting:
- Use
indirect lighting sources and task lights.
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Use low-glare bulbs or cover bright bulbs with filters.
- Adjust
light levels by turning off light banks or using
adjustable light switches.
- Avoid
sitting so that overhead lights are within your
visual field.
- Wear
a visor to shield your eyes from bright overhead
lights.
- Reduce
light from windows with shades or room partitions.
- Sit
at right angles and at least 3 feet from windows.
- Avoid
glossy, reflective wall paint or reflective light-colored
work surfaces.
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Reduce
glare. If you can see your own reflection
or the reflection of windows and lights in your monitor
screen, you have a glare problem.
- Use
a monitor visor to reduce glare from overhead lighting
sources.
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Consider using a good quality glare guard. Use a
polarized filter if you sit near a window.
- Adjust
the monitor tilt to avoid reflections from windows
and ceiling fixtures.
- Adjust
screen/character background. Use dark characters
on a light background. White characters on a blue
background can provide positive contrast while limiting
glare often seen on a white background.
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Select
a high quality monitor. Size is not the
only consideration.
- Select
a monitor large enough for the work you complete.
The size of the text should be three times the size
of the smallest text you can read. If you work with
spreadsheets, you will need a larger screen to view
your work.
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If you don't need a color monitor, consider a monochrome
monitor with higher screen resolution.
- Adjust
contrast level to maximize character definition.
- Select
a color monitor with dot pitch less than.28mm.
- Use
refresh rates above the standard 60 Hz default setting
to reduce flicker. A minimum of 70 hertz is recommended.
- Select
a screen with good screen resolution (more pixels).
Make sure you don't compromise resolution for a
lower refresh rate. Both are important.
- Adjust
the screen brightness to match the general brightness
of the room.
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Set
up your monitor to reduce
eye and neck strain.
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Position the center of the screen 10-20 degrees
below your straight-ahead gaze. You should be able
to look at your screen without tilting your head.
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The closer an object, the harder your eyes work
to focus. Place the screen as far away as possible,
provided you can read it easily. Adjust font size
if necessary.
- Keep
the screen and source documents at about the same
distance away from you to avoid constant re-focusing
while working.
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Use
good work habits.
- Eyestrain
can result from dry eyes. Blinking helps lubricate
your eyes. Post a "Blink" post-it note
on your monitor to remind you to blink while working.
- Follow
the "20-20-20 rule". Every 20 minutes,
look 20 feet away for 20 seconds to rest your eyes.
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