Long hours at a computer can harm your eyes, say experts. They advise frequent short breaks every half hour or so to minimize the damage. Studies have shown that eyestrain and other vision problems can be found in as much as nine out of ten people using computers often, say Kerry Beebe, an optometrist and spokesman for the American Optometric Association. The most common symptoms are eyestrain, blurred vision, double vision, excessive tears, dry eyes and excessive blinking or squinting. Visual problems can also result in physical problems such as headaches and neck or shoulder pain, reported Health Central. So this means you must never use a computer non-stop without taking any breaks – you should always take breaks to reduce the risk of any of these eye and body problems.