Staring at a computer monitor for hours at an end has become a part of the daily modern workday. And inevitably, all of that staring can literally strain your eyes; especially if you have been diagnosed with dry eye.
The results of a new study have shown that staring at a computer screen for long can change the eyes’ tear fluid. The cells in our upper eyelid secret a protein called MUC5AC, which is a part of the normally occurring mucus layer or “tear film.” This layer keeps our eyes moist. During the study it was observed that participants with most screen time had MUC5AC levels nearing those of people diagnosed with 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 ophthalmologist at the School of Medicine at Keio University in Tokyo and author of the new study.
“When we stare at computers, our blinking times decrease compared to reading a book at the table,” he told Reuters Health by email. He added that people, who stare at screens, tend to open their eyelids wider than while doing other tasks. This extra exposed surface along with infrequent blinking can hasten tear evaporation. This is how the habit is associated with dry eye disease.
According to previous researches, millions of people in the US and Japan suffered from dry eye disease or reported that its symptoms were often associated with computer work.
96 Japanese office workers (2/3 of them men) were tested for their tears in both eyes during the study. The researchers measured the amount of MUC5AC in the total protein content of their tears.
Out of these participants, the ones who had jobs involving computer screens were asked to fill out questionnaires about their working hours and eye problem symptoms (if they had any). Dry eye disease was observed in seven percent of men and 14 percent of women.
These people had reported symptoms like eye irritation, burning or blurred vision and had poor quality or quantity of tear film, according to test reports. The average amount of MUC5AC was about 6.8 nanograms per milligram of protein in each eye in people who looked at screens for work just over eight hours a day.
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 with 9.6 ng/mg in people who spent fewer than five hours daily infront of 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.
“Mucin is one of the most important components of the tear film,” said Dr. Yuichi Hori, hair of the department of Ophthalmology at Toho University Omori Medical Center in Tokyo, 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,” he added.
People with eye strain symptoms also had lower concentration of protein as compared to people without them. Uchino told that this concentration makes people less productive and they are more likely to be depressed.
However, with simple changes, office workers can ward off the risk of developing dry eyes. “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.” The results of the study were published in JAMA Ophthalmology.
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