Yes, staring at a screen all day DOES damage your eyes, and here's how
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Tears keep your eyes healthy, clean and lubricated. People who do not produce enough tears suffer from a condition known as dry eye, in which not enough moisture is produced to keep the surface of the eyeball lubricated. This leads to pain, grittiness, vision blur and stinging. According to the authors of a new study published in JAMA Ophthalmology, people who spend more than seven hours per day in front of a computer screen may experience similar symptoms. 

Researchers in Japan recruited 96 volunteers (60 men and 36 women) whose job requires long sessions in front of a screen. The scientists measured the quantity of the protein MUC5AC in the office workers' tears and asked them to fill in a questionnaire. MUC5AC is found in ‘tear film’, a layer of mucus that keeps the eye moist and is necessary for good vision, explained Robert T. Gonzalez at io9. 

When we stare at screens we blink less frequently and tend to open our eyes wider than when performing other tasks, such as reading a book, which contributes to faster tear evaporation. According to the study, people who continuously stare at computers screens have MUC5AC concentrations almost as low as those that have been diagnosed with dry eye. 

Participants who work with computer screens for more than seven hours a day had an average of 5.9 ng/mg of MUC5AC, while those who spend fewer than five hours in front of a monitor had 9.5 ng/mg. In comparison, people who definitely have dry eye measure an average of 3.5 ng/mg of MUC5AC, while people without the disease have 8.2 ng/mg. 

So what to do to keep your eyes moist and healthy? Doctors recommend keeping a humidifier in your office space and avoiding direct contact with air conditioners. One of the authors, Dr Yuichi Ochino also recommended over at The Independent: “The exposed ocular surface area can be decreased by placing the terminal at a lower height, with the screen tilted upward”.

Sources: The Independent via io9