I've been reminded to take care of my eyes, and not overstrain them when using the computer - which I do for several hours every day, being a writer. A New York Times article last year shed light on the subject.
... computer vision syndrome ... can affect anyone who spends three or more hours a day in front of computer monitors, and the population at risk is potentially huge.
Worldwide, up to 70 million workers are at risk for computer vision syndrome, and those numbers are only likely to grow. In a report about the condition written by eye care specialists in Nigeria and Botswana and published in Medical Practice and Reviews, the authors detail an expanding list of professionals at risk — accountants, architects, bankers, engineers, flight controllers, graphic artists, journalists, academicians, secretaries and students — all of whom “cannot work without the help of computer.”
And that’s not counting the millions of children and adolescents who spend many hours a day playing computer games.
Studies have indicated 70 percent to 90 percent of people who use computers extensively, whether for work or play, have one or more symptoms of computer vision syndrome. The effects of prolonged computer use are not just vision-related. Complaints include neurological symptoms like chronic headaches and musculoskeletal problems like neck and back pain ... eye symptoms, low back pain, tension headache and psychosocial stress.
Still, the most common computer-related complaint involves the eyes, which can develop blurred or double vision as well as burning, itching, dryness and redness, all of which can interfere with work performance.
There's much more at the link, including a more detailed analysis of risks and effects, and ways to help undo the damage they cause. Recommended reading.
Interestingly, I'm finding that strength training is helping me to overcome one problem associated with computer vision syndrome. I was developing a very pronounced "hunchback" type of hump behind my neck, caused by craning forward to see text on a computer screen through tired eyes. Weight training has helped to straighten my neck and improve my posture, so that in three months the "hump" is more than half gone. I reckon in another few months, it'll have disappeared entirely - a serendipitous side effect of a completely unrelated health decision.