Yahoo News has published a very useful article about the effects on the eyes of prolonged staring at a computer screen. Here's an excerpt.
Office workers who spend long hours looking at computer screens have changes in their tear fluid similar to people with the disease known as dry eye, according to a study from Japan.
The protein MUC5AC, secreted by cells in the upper eyelid, makes up part of the normally occurring mucus layer, or “tear film,” that keeps the eye moist. But study participants with the most screen time had MUC5AC levels nearing those of people with diagnosed dry eye.
. . .
“When we stare at computers, our blinking times decreased compared to reading a book at the table,” [Dr. Yuichi Uchino] told Reuters Health by email.
People staring at screens also 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, he said.
Dry eye may be chronic for some but can be managed with over the counter or prescription eye drops.
Past research suggests that up to 5 million men and women over age 50 in the United States suffer from dry eye disease, the researchers write in their report. In Japan, tens of millions of people report some dry eye symptoms, often associated with computer work, they add.
. . .
Office workers who are worried about dry eye can make some simple changes to decrease their risk, Uchino said.
“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.”
There's more at the link. Very important and highly recommended reading for all who spend more than an hour or two a day using a computer.
I'm living proof of the seriousness of this problem. Shortly after I began writing full-time my eyes became very irritated and painful. An opthalmologist diagnosed 'filamentary keratitis', and had to remove the filaments under a local anesthetic. I had to have that done several times as the condition recurred. It was very unpleasant, to say the least. Eventually I learned to keep my eyes very well lubricated, using lubricant eye drops several times during the day and lubricating ointment at night. (The latter is usually petroleum jelly based, and obscures one's vision quite severely, but if one uses it while asleep that doesn't matter. It can be removed easily by wiping the eyes with a facecloth moistened with hot water when one awakes, followed by lubricant eye drops to take care of any remaining residue.) I still follow that treatment regime when I'm in a heavy writing mode (as I am right now, with Maxwell Volume 4 in preparation and Laredo Volume 2 in the initial planning stages).
I think the article's advice is very good, based on my extensive personal experience of the problem. It's even more important if you use contact lenses or work in a very dry environment.