Maybe well will have more end users of adapted computer equipment sooner
then we think. Check out the figure that 70 percent of those in the
computer industry have eye problems.
kelly
from the New York times
Technology - Circuits
June 11, 1998
Focusing on Computer Users' Eyestrain
By ANNE EISENBERG
For many people, working in front of a computer monitor means
aching eyes, blurred vision and even migraines. Eye and vision
problems are fast overtaking sore wrists and hands as one of the
most frequently reported health-related complaints among the
ever-growing numbers of people who spend time peering at a computer
screen.
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"There is no disagreement among experts that we're seeing more and
more computer-related vision problems," said Dr. Kent M. Daum, an
optometrist and professor at the University of Alabama School of
Optometry in Birmingham who has written a number of papers on
computer-related eye strain. "The eye isn't meant to close-focus
all day. Doing so can lead to considerable problems."
So quickly have computer-related vision issues grown in the past
year that the Occupational Safety and Health Administration of the
Federal Department of Labor is considering incorporating these
issues into the ergonomic guidelines that it is developing. "Right
now, the standard targets people in manufacturing," said David
Cochran, who directs the agency's work on the guidelines. "We're
still wrestling with how to deal with offices and computer work
stations."
Surveys cited by the American Optometric Association, an
organization of 32,000 optometrists, indicate that 70 percent to 75
percent of computer workers have eye and vision problems.
"My eyes start to burn before I get far into the day," said Leah
Krawetz, who runs a travel agency in St. Paul, Minn. "Right now,
they are killing me, and no wonder -- I'm working on an airline
reservation from here to Birmingham, England, to Oslo, Norway, and
back, all within a budget of $1,500 to $1,600. That's a guaranteed
recipe for eye strain."
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Soreness, blurry vision and even migraines can follow too much screen
time.
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Blurred vision, along with aching, stinging eyes, is one of the
most common complaints related to computer use.
"Some blurred vision comes about because of incorrect glasses or
contact lenses," Dr. Daum said. "But that is not the only reason.
The process of reading up close requires a muscular effort.
People who challenge the muscle may have what are called spasms of
accommodation. When they look up into the distance, the mechanism
to focus is locked into place; everything seems fuzzy."
The fuzziness abates in about 15 minutes for a person in good
health, he said, but if someone is worn down or continues to abuse
the eyes with long periods of close work, "the eye cannot easily
recover from the spasm or goes into involuntary spasm, a condition
that's very hard to manage," Dr. Daum added.
Working in front of a computer may also induce other serious
problems. Dr. Ronald Burd, director of ophthalmology at Albert
Einstein College of Medicine-Montefiore Medical Center in the
Bronx, said that computer monitors could occasionally trigger
ocular migraines.
"Ocular migraine is not one disease process but instead a main
highway with many roads to it," Dr. Burd said. "Some people are
sensitive to red wine or blue cheese. Some small group of people
who have migraines are very sensitive to the computer. I think
perhaps the rhythmicity of the pixels in the display stimulates
them."
Many optometrists view computer-related vision problems as a form
of repetitive stress injury. "Symptoms are associated with
repetitive muscular activity: frequent eye movement from documents
to screen and from screen to keyboard," said Dr. Jeffrey L. Weaver,
director of the Clinical Care Center for the American Optometric
Association. "Just like other forms of R.S.I., the problems take
time to develop and lots of time for recovery."
What can computer users do to guard against vision-related
problems?
"Often users need a specific set of glasses for working at a
computer," said Dr. Marcel J. Sislowitz, a Manhattan
ophthalmologist and surgeon who draws a parallel between computer
users and musicians. "If I give a piano player glasses suitable for
reading a book, the glasses won't work -- he'll have to lean
forward to get the score in focus. It's the same for a violin
player or a computer user. Both need prescriptions specific to the
task."
Photo caption:
Credit:Chester Higgins Jr./The New York Times
An eye test given by Dr. Gary Tracy, an optometrist in Manhattan, used
a simulation of the way people view computer screens.
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More than half the people in the United States wear eyeglasses or
contact lenses to correct vision, Dr. Weaver said, citing figures
compiled by the American Optometric Association.
"Conservative estimates put the number at at least 147 million."
For computer-related eye problems, doctors sometimes advise a step
as simple as blinking, both for patients who wear corrective lenses
and those who do not.
Dr. Michael Weiss, an ophthalmologist who practices at
Columbia-Presbyterian Medical Center in New York City, explained
how eye dryness played an important role in causing eyes to ache.
"People get so involved with reading material on the computer that
they don't blink regularly," he said. "It's very similar to what
happens to drivers at night, when they concentrate on the road,
forget to blink and experience eyestrain. The cornea isn't
lubricated, and then they feel all sorts of sensations as the eye
tells them they have a problem."
Dr. Weiss recommends that computer users close their eyes for
breaks and blink frequently. Those who wear contact lenses, in
particular, should use lubricants or artificial tears.
"The most natural way to treat this is to take a break," he
advised.
The newer generation of glare filters may also help; earlier ones
were often accused of diffusing the images.
Prof. Bob Beaton, a researcher at Virginia Tech in Blacksburg who
has worked on glare filters for 15 years, said properly designed
antireflection filters improved contrast, making the screen easier
to see.
"Concern about eyestrain at the computer is universal," said
Professor Beaton, who works on several international committees.
"People often set brightness inappropriately, unaware that
brightness and contrast work together. Turn up the brightness, and
eventually the characters get fuzzier and lose contrast; the edges
of the image thicken with brightness.
A filter helps when circuitry on the computer can't make the screen
bright enough for the contrast users want."
photo caption:
Credit:Chester Higgins/The New York Times
New Approach: An eye testing device uses pixel-like dots. Unlike paper
images, computer images are brighter in the center.
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Professor Beaton said filters had little, if any, effect on the
resolution of the display. "The newer models are basically as clear
as glass and do not blur or fuzz the displayed image," he said.
"They can attenuate or minimize refections of a bright office or a
bright shirt. Make sure light is not cast directly on the screen
from windows, then adjust the monitor properly so that it is bright
but sharp."
Looking down at the monitor, typically 10 to 20 degrees below the
straight-ahead position of the head -- not up -- is also a good
practice, said Dr. James Sheedy, a clinical professor of optometry
at the University of California at Berkeley. "And if possible," he
added, "make sure you're looking down at a large monitor with high
resolution."
Humble steps like cleaning the screen may also be in order. "A
thumbprint from peanut butter can give off a horrendous
distortion," said Dr. Gary Tracy, a New York City optometrist who
once came home from work to confront just such a smudge on his home
computer. Dr. Tracy recommends even illumination in rooms where
computers are used. "Working in the dark is hard on the eyes," he
said.
If all else fails, a user might consider an eye test in which
conditions working with a computer are simulated. Dr. Tracy
occasionally uses such simulations in analyzing the eyesight of
people who use computers for many hours daily. "Some people's eyes
are thrown off by the fuzziness of letters in a computer display,"
he said. "In such cases, the test gives helpful information."
Dr. Daum is not sure that such tests lead to better prescription
glasses or contacts. "I'm not sure it makes enough of a difference
for such a test to be useful," he said.
For now, many doctors advise a pragmatic approach to identify
factors that may cause eye problems. "Computer users should look at
the entire environment," said Dr. Cosmo Salibello, an optometrist
who has spent 16 years doing research on eyestrain. "Glare will add
to eyestrain even with the best screen resolution and
character-background display, as will eyes that are not properly in
focus for the screen distance. All the factors need to be
considered."
Copyright 1998 The New York Times Company
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