According to the Sight and Hearing Association, your eyes aren't really being strained. Instead, it's the muscles that are used for eye movement and focus that grow weary from too much use in adverse conditions.

As a result of increased computer use, computer vision syndrome (CVS) — eye and vision problems linked to extended computer use that can affect adults and children — is an increasingly common affliction. Symptoms include dry, irritated, inflamed or sore eyes; headaches; and blurred vision.

Eye strain is the most common symptom of computer vision syndrome. Other symptoms include headaches, tired or burning eyes, slow focusing, blurred vision at distance, neck pain, and shoulder pain. In fact, recent published studies show that computer eye strain can significantly affect productivity and accuracy in the workplace.

The good news? "CVS makes you feel lousy but it won't cause permanent damage to the eye," says Dr. Paula Gaudet, a Halifax optometrist and past president of the Nova Scotia Association of Optometrists, who estimates that as many as 25 per cent of her patients have CVS.

Eyeglasses, contact lenses and reading glasses don't solve the problem of computer vision syndrome. This is because they are designed for focusing at distance or at near, but not at the intermediate distance where your eyes view your computer screen.

Special computer glasses, which are usually prescribed by your optometrist, cost from $145 to $200 and help your eyes focus on the screen. While they can help grown-ups, children generally don't need them. "Kids' focusing power is so strong that they don't have the same vision problems that adults do in this situation," explains Dr. Gaudet. If your son or daughter complains about sore eyes, an optometrist-recommended eye lubricant should offer relief.

"The best treatment for kids is prevention," she says. "Limit your children's time on the computer so they don't end up with eye strain."