The American Optometric Association is advising that people working in front of computers walk away from them every half hour.

AOA spokesman Kerry Beebe said that its studies show that nine out of ten people who use a computer for long hours can suffer from eyestrain and other vision problems. The most common symptoms are eyestrain, blurred vision, double vision, excessive tears, dry eyes and excessive blinking or squinting.

Too long in front of the computer can result in physical problems such as headaches and neck or shoulder pain.

Apparently the radiation put out by a computer screen has nothing to do with these symptoms, although that's a common myth. 

People should take frequent short breaks, every half hour or so, for a minute or two and fix your eyes on a distant object to help refresh your vision.

Monitor should be adjusted so they are not too bright or too dim.