|
A
Dozen Things You Should Know about Eyestrain |
| 1. |
Eyestrain
means different things to different people. It can be experienced
as burning, tightness, sharp pains, dull pains, watering, blurring,
double vision, headaches, and other sensations, depending on the person.
If you have any eye discomfort caused by viewing something, you can
call it eyestrain. |
| 2. |
In
VDT workstations, the principal factors affecting the ability to see
well are:
- glare
- the
luminance (brightness) difference between what is being looked
at and its immediate environment
- the
amount of light
- the
distance between the eye and the screen and document
- the
readability of the screen and document
- the
worker's vision and his or her corrective lens
|
| 3. |
Watch
out for direct glare. Direct glare involves a light source shining
directly into the eyes --- ceiling lights, task lights, or bright
windows. To determine the degree of direct glare, you can temporarily
shield your eyes with a hand and notice whether you feel immediate
relief. |
| 4. |
Reflected
glare, such as on computer screens, sometimes causes eyestrain. But
its worst effect may be causing you to change your posture to an uncomfortable
one, in order to see well. |
| 5. |
The
most overlooked cause of eyestrain in offices is contrast --- usually,
a dark screen surrounded by a bright background such as a window or
a lit wall. The best solution is to find a way to darken the area
around the screen. This problem occurs mainly on screens with light
letters on a black background. |
| 6. |
How
much light is right? It depends on your age, the quality of the print
you're reading, and other factors. There should be plenty of light
for easy reading, but too much can, depending on the person, cause
eyestrain. |
| 7. |
Eyes
are strained more by close viewing than by distant viewing. The "right"
distance for computer monitors and documents depends entirely on how
clearly they can be read at a given distance. The general rule is
to keep viewed material as far away as possible, provided it can be
read easily!!! |
| 8. |
If
you gaze at something too long, your eyes can tire. Eyes need to focus
at different distances from time to time. It's a good idea to follow
the "20/20 rule" --- every twenty minutes, look twenty feet
away for twenty seconds. |
| 9. |
If
two objects are only a couple of inches different in their distance
from the eyes, the eyes actually do NOT have to refocus to look from
one to another. Greater distance differences, however, can overwork
the eyes if you have to look from one object to another frequently
- -- as when typing from printed copy and looking at the screen. In
general, keep viewed objects at about the same distance if you have
to look back and forth a lot. |
| 10. |
Can
computer work cause nearsightedness? Rarely, according to optometrists.
It's more likely that computer work makes you realize that you need
glasses. |
| 11. |
Sometimes
eyestrain is just a case of dry eyes. Lowering the monitor can
help. Looking downward means more of the eye surface is covered
by the eyelid, and two other things happen: the eyes unconsciously
blink more, and they produce more lubrication. |
| 12. |
People
who need bifocals should consider other options besides bifocals.
Two good ones are:
- "Computer
glasses" that focus at the right distance for the computer
screen.
- Wearing
contact lenses --- corrected for computer or reading distance
in one eye, and for far distance (if needed) in the other eye.
Some
optometrists have taken special training in computer-related vision.
|
| 13. |
Bifocal
wearers often experience sore necks and shoulders because they have
to tip their heads back to see the computer screen.
- Lower
the screen as much as possible --- if it sits on the CPU, move
the CPU.
- If
necessary, remove the monitor's tilt-swivel base (consult a computer
hardware person first) to gain a couple additional inches.
- Lower
the work surface that the monitor sits on
|
