If you spend a lot of time on a PC and think you've developed dry eye disease, you likely haven't, according to new research, but you are likely suffering similar symptoms. It seems those who stare at computer screens all day are experiencing some eyelid cell changes that mimic the chronic ailment.

The big symptom is a tearing of the eye, a watering, and soreness in the eyelid. That's because the protein called MUC5AC released by cells in the upper eyelid is inflamed. The MUC5AC is part of the normally occurring mucus layer that helps keep eyes moist. The research indicates steady hours of screen viewing can cause them to dry out and impair the natural tear fluid.

"To understand patients' eye strain, which is one of major symptoms of dry eye disease, it is important that ophthalmologists pay attention to MUC5AC concentration in tears," said study author Dr. Yuichi Uchino, an ophthalmologist at the School of Medicine at Keio University in Tokyo.

Viewing a PC for long periods can decrease an eye's blinking time much more than reading a book, explained the study's authors. Blinking helps keep an eye moist.

According to the researchers, tens of millions in Japan are suffering from some symptom of dry eye, a chronic ailment that can be managed with over-the-counter drops or even prescription drops.

The Japanese research team's study involved 96 office staffers, mostly men, and measured the total protein levels. Those involved completed surveys related to work and eye issues.

Of the participants, 14 percent of the women and 7 percent of the men were deemed to be suffering from "dry eye disease," and complained of burning, blurry vision and irritation of the eye.

Earlier research indicates up to 5 million U.S. men and women over age 50 suffer from dry eye disease, the researchers write in their report.

"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," Dr. Yuichi Hori, who was not a part of the new study, said. "And they should ask an eye care doctor if their symptoms still remain."