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 The protein MUC5AC, secreted by cells in the upper eyelid, makes up
part of the normally occurring mucus layer, or “tear film,” that
keeps the eye moist. But study participants with the most screen
time had MUC5AC levels nearing those of people with diagnosed dry
eye.
“To understand patients' eye strain, which is one of major symptoms
of dry eye disease, it is important that ophthalmologist pay
attention to MUC5AC concentration in tears,” said Dr. Yuichi Uchino,
an author of the new study.
Uchino is an ophthalmologist at the School of Medicine at Keio
University in Tokyo.
“When we stare at computers, our blinking times decreased compared
to reading a book at the table,” he told Reuters Health by email.
People staring at screens also tend to open their eyelids wider than
while doing other tasks, and the extra exposed surface area in
addition to infrequent blinking can accelerate tear evaporation and
is associated with dry eye disease, he said.
Dry eye may be chronic for some but can be managed with over the
counter or prescription eye drops.
Past research suggests that up to 5 million men and women over age
50 in the United States suffer from dry eye disease, the researchers
write in their report. In Japan, tens of millions of people report
some dry eye symptoms, often associated with computer work, they
add.
The study team tested the tears from both eyes of 96 Japanese office
workers, about two-thirds of them men, and measured how much of the
total protein content of the tears was MUC5AC.
Workers employed in jobs involving computer screens filled out
questionnaires about their working hours and symptoms of any eye
problems.
Seven percent of men and 14 percent of women were diagnosed with
‘dry eye disease,’ meaning they reported symptoms of eye problems
like irritation, burning or blurred vision and had poor quality or
quantity of tear film, according to the tests.
Overall, participants looked at screens for work for just over eight
hours a day and had an average of about 6.8 nanograms of MUC5AC per
milligram of protein in each eye.
However, people who worked with computer screens for more than seven
hours per day had an average of 5.9 ng/mg of MUC5AC, compared to 9.6
ng/mg for people who spent fewer than five hours daily with screens.
Similarly, people with definite dry eye disease had an average of
3.5 ng/mg of MUC5AC compared to 8.2 ng/mg for people without the
disease.
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“Mucin is one of the most important components of the tear film,”
said Dr. Yuichi Hori, who was not a part of the new study. “Mucins
(like MUC5AC) function to hold water on the ocular surface of the
epithelia that synthesize them, hence, they are major players in
maintenance of the tear film on the ocular surface,” Hori told
Reuters Health by email.
He is chair of the department of Ophthalmology at Toho University
Omori Medical Center in Tokyo.
Concentration of the protein was also lower for people with symptoms
of eye strain than for people without symptoms, according to the
results published in JAMA Ophthalmology.
People with dry eyes at work tend to be less productive and are more
likely to be depressed, according to previous studies, Uchino said.
Office workers who are worried about dry eye can make some simple
changes to decrease their risk, Uchino said.
“The exposed ocular surface area can be decreased by placing the
terminal at a lower height, with the screen tilted upward,” Uchino
said.
Doctors also recommend using a humidifier at the office and avoiding
being in the direct path of the wind from an air conditioner, he
said.
“We advise the office workers suffering from ocular fatigue and dry
eye symptoms that they should blink more frequently in an intended
manner during (screen use), and that they should use artificial
tears,” Hori said.
“And they should ask an eye care doctor if their symptoms still
remain.”
SOURCE: http://bit.ly/1oTQ4ov
JAMA Ophthalmology, June 5, 2014.
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