People who spend their working hours staring at a computer screen have changes in their tear fluid typical of those who have been diagnosed with the disease dry eye, according to the results of a new study.

A particular protein called MUC5AC makes up part of the normally occurring mucus layer, or “tear film,” that keeps the eye moist.

But a study found participants who spent the most time sat in front of a screen had levels of MUC5AC nearing those of people who had been diagnosed with dry eye.

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'Dry eye' is condition that occurs when the eyes do not make produce enough tears or the tears evaporate too quickly.

A team tested the tears from both eyes of 96 Japanese office workers and measured how much of the total protein content of the tears was MUC5AC.

Those who had jobs that involved looking at computer screens filled out questionnaires about their working hours and symptoms of any eye problems.

Dr. Yuichi Uchino, an author of the study, said people staring at screens generally 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.

“When we stare at computers, our blinking times decreased compared to reading a book at the table," he added.

The team found participants who worked with computer screens for more than seven hours each 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.

In comparison, 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.

Office workers who are worried about dry eye can make some simple changes to decrease their risk, Dr Uchino said.

“The exposed ocular surface area can be decreased by placing the terminal at a lower height, with the screen tilted upward,” Dr 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 added.

The study, Alteration of Tear Mucin 5AC in Office Workers Using Visual Display Terminals, has been published in the journal Jama Ophthalmology.

Additional reporting by Reuters