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Frequently Asked Questions
Computers and the Eye
What kind of problems are associated with computer use?
Why do we experience eyestrain?
What can I do to reduce eyestrain?
How do "computer glasses" reduce eyestrain?
What should I look for in computer glasses?
Can I use my reading glasses to relieve eyestrain?
How do I reduce headaches, neck and/or shoulder pain?
What can I do about sore and dry eyes?
What kind of problems are associated with computer use?
People who spend a long time in front of computer screens may complain
of eyestrain (tired eyes, loss of focus), headaches and sore or dry eyes.
Some complain of neck and shoulder pain, which are related to posture
rather than the eyes.
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Why do we experience eyestrain?
Normally, while we are relaxing, our eyes are focused at distance. To
read, to watch the computer monitor or to do any other detailed near task,
we unconsciously use our eye muscles. The muscle inside the eye contracts
to focus the lens for the near task. For as long as we are performing
the near task the muscle continues to work and remains contracted. Eventually
the eye muscle gets tired and we experience eyestrain. Unlike the well-defined
edges of the printed page, monitor pixels create a fuzzy edge around typefaces
and pictures. This makes it more difficult for the eyes to focus and the
eyes get tired sooner than when reading a book.
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What can I do to reduce eyestrain?
- Reduce screen glare (with screen antiglare accessories).
- Turn off bright overhead fluorescent lights; use soft indirect lighting.
- Take short "eye breaks" by relaxing briefly and looking at some distant object or out a window for a few seconds every 10-15 minutes.
- Larger monitors and non-interlaced screens may be of value. The effect of changing monitor size is somewhat unpredictable.
- Use "computer glasses".
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How do "computer glasses" reduce eyestrain?
If your eyes tire quickly during computer work you may want to use glasses
that will focus your eyes on the plane of the computer screen ("computer
glasses"). Measure your usual working distance from the eye to the screen
with a ruler (do not estimate). Measure several times, preferably at different
times of the day. Then average the distances and have the glasses made
to focus at that distance. This will allow your eye muscle to remain in
its relaxed state and reduce eyestrain.
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What should I look for in computer glasses?
Computer glasses should preferably be "full frame", rather than the sometimes
fashionable small frame type. They may be "single vision lenses" or they
may be made as bifocals by adding a lower segment for reading. Avoid progressive
power lenses (no line bifocals). The intermediate power corridor of no-line-bifocals
is too narrow to allow in-focus gaze shifts from one part of the computer
screen to another.
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Can I use my reading glasses to relieve eyestrain?
If your reading glasses relieve the eyestrain, then do use your reading
glasses. The problem with reading glasses is that they usually require
you to lean forward, to get close to the screen, in order to see clearly.
This may cause posture problems with neck and shoulder pain or discomfort.
If you experience these, you may change to computer glasses. Computer
glasses are similar to reading glasses, but are not as strong. This allows
you to sit straight rather than lean forward to view the screen.
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How do I reduce headaches, neck and/or shoulder pain?
Reposition the screen height. The top of the monitor needs to be below
eye level. This may require removing the CPU and even the swivel base
from under the monitor. When the screen is placed too high (above eye
level), forehead muscles contract causing headache and fatigue. Increasing
font size may help. Computer glasses may help if you find yourself leaning
forward to view the screen.
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What can I do about sore and dry eyes?
We normally blink 15-20 times per minute. When you concentrate on the
screen, you blink less often than normal, sometimes down to 3 times per
minute. This affects lubrication of the eye surface, which may become
excessively dry. You may feel as if there is something in your eye, or
the eye may be sore or it may feel dry.
Deliberately blinking often (e.g. at the end of each line, or whenever you think of it) may relieve the problem. Use of artificial tears before starting and/or during work may be useful. They are available without prescription. Choose non-preserved artificial tears. They can be used as often as every hour. I do not recommend preserved tears or contact lens re-wetting drops for hourly usage because of preservative toxicity, which with hourly use may make the symptoms worse.
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