Staring at a screen is altering your tears, study finds

A study found that focusing on a screen for many hours alters tear composition

Published September 15, 2014 10:11PM (EDT)

Spending hours staring at screens is taking a toll on our eyes -- and our tears -- a new study says. Scientific American reports that folks "peering for hours into a screen tend to blink less often and have tears that evaporate more quickly which dries out the eye and can cause blurred vision or pain."

In short, staring at a screen for multiple hours a day can lead to dry eye, and dry eye, if not dealt with, can cause corneal ulcers and scarring.

A study published in the journal JAMA Ophthalmology, in June, examined this correlation.

Tears are not just a byproduct of crying, as AsapSCIENCE notes, they also act as natural lubricants for eyes, and remove irritants.

The tears of people with dry eye are slightly altered; they have less of mucin 5AC, a protein "which normally helps to keep tears sticky and spread evenly across the eye," Scientific American explains.

The study examined 96 Japanese people who worked in an office environment, where they stared at a screen for eight plus hours. Researchers found that looking at the screen for this amount of time was "associated" with tears that had lower mucin levels. From the study:

"The data obtained in the present study suggest that office workers with prolonged VDT [visual display terminal] use, as well as those with an increased frequency of eye strain, have a low MUC5AC [mucin AC5] concentration in their tears. Furthermore, MUC5AC concentration in the tears of patients with DED [dry eye disease] may be lower than that in individuals without DED.

The screen-staring induced damage is not permanent, however. "Certain molecules that help to produce mucin remained roughly equal among test subjects with and without dry eye, regardless of their eyestrain status," Scientific American stated.

Though this study was done on a small scale, this research does give insight into dry eye and mucin levels. On a larger scale, more research will need to be done.

In more practical terms, try to step away from the screen, get up, and take a walk -- presumably one where you're not just staring at a smartphone.

By Sarah Gray

Sarah Gray is an assistant editor at Salon, focusing on innovation. Follow @sarahhhgray or email

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Eyes Health Screens Study Tears Technology