Health & Wellness
Much Computer Eye Strain Caused by
Poor Lighting and Posture
Dr. Mark Sibley
I receive so many
questions from people who use computers. They have eye symptoms
and ask, "Is it the computer or is it the work that bothers my
eyes?"
It seems that we have all traded typewriters for computer screens.
More and more people in our population are spending their works
days or evenings looking at the computer video display terminal
(VDT) screens. More and more people are complaining of headaches,
eyestrain, blurry vision, and a long list of other symptoms.
The environment has changed from when our parents worked on manual
typewriters and adding machines using the light from light bulbs.
We now work on computer (VDT) screens using flourescent lights
that cause increased glare and increased light sensitivity
symptoms. The VDT in everyone's workplace now places different
visual demands on people's eyes.
To understand the increase in visual complaints of eyestrain and
headaches that VDT workers experience, let's look at the
differences from our parents' workplace.
Ink on paper from a typewriter or in a book is seen as a solid,
dark image. This is comfortable on your eyes for reading for
prolonged periods. However, the computer letters are not the dark,
crisp printed image that we can keep in focus. The VDT image is
blurrier and difficult to focus on because of the depth of the
lighted image on the VDT glass screen. There is actually depth to
the VDT computer letters, and this tricks our eyes into constantly
focusing a little bit "in and out." This makes the eyes work a
little harder attempting to "auto-focus" over the entire workday.
This brings on the increased symptoms.
One of the most commonly asked questions is, "Are computer video
display screens (VDTs) harmful to my eyes?"
I am glad to tell you the answer is no. Extensive private and
government research studies have not shown any evidence that VDTs
are harmful to your eyes. But totally aside from the question of
being harmful or damaging to the eyes is the question of physical
discomfort. Most complaints, which include visual discomfort, eye
strain, eye irritation, back aches and pain of a muscular nature,
have been found to be associated with work place posture and the
total ergonomics of the eyes, head, neck and seating posture.
Much of the eyestrain and symptoms is usually caused by poor
lighting, improper placement of the reading supplies, computer
screen or keyboard. We have found that the type of lighting used
in the office and the level of reflection from work surfaces can
be changed to improve the comfort of employees. Computer users
have the capability to reduce fatigue on their eyes by getting
filters or tints in their eyeglasses, by getting glasses
specifically for computer use, or by getting coatings or filters
on their VDT screens at work.
Here is a checklist to evaluate your computer situation:
1. The top of the VDT screen should be placed slightly below eye
level.
2. Your reference material should be placed on a document holder
and moved close enough to the screen so that you do not have to
swing your head and eyes back and forth from your material to the
VDT screen. Otherwise, your eyes are constantly changing focus,
and your muscles can become stiff and sore, and your eyes can
fatigue quicker, causing eyestrain and headache symptoms.
3. Try adjusting your lighting to eliminate or decrease glare and
harsh reflections. If office lighting or window shades cannot be
modified, hoods or VDT filters may decrease the problems.
4. A frequent break in eye usage by simply glancing out the window
or looking 20 feet away will help. Simply standing up and
stretching in place for 5 seconds will reduce fatigue.
5. Research shows that working on a computer reduces normal
blinking by half, from 20 times a minute, to 10 times a minute. To
keep the eyes from drying out and feeling hot, tired and itchy,
try blinking more rapidly every once in awhile or occasionally
closing your eyes for a few seconds, alternating with the looking
at a distant object.
6. Anyone with diagnosed dry eyes would benefit from using
artificial tears occasionally (or frequently) combined with the
above recommendations.
7. Get a good check-up from your optometrist or family eye doctor
if problems persist, since the proper prescription or computer
vision lenses may be needed for the most comfortable vision.
It is reported that more than 20 million workers in America
experience VDT eyestrain. As mentioned, other factors to help
relieve the strain include adjustment of your chair's height to
allow your feet to reach the ground and rest comfortably. Also,
your keyboard should rest below your desktop, if possible. And try
to insure that your wrists have proper supports.
In summary, the VDT computer screen is here to stay, and you must
do a few things to help yourself remain comfortable while at work
or having fun on your computer.
Dr. Mark Sibley,
M.D., F.A.C.S., is a Board Certified Ophthalmologist and laser
specialist who practices locally. He is medical advisor to the
Society to Prevent Blindness and to the American Diabetes
Association, and is team ophthalmologist for the Devil Rays.
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