Computer vision syndrome (CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time. Some symptoms of CVS include headaches, blurred vision, neck pain, redness in the eyes, fatigue, eye strain, dry eyes, irritated eyes, double vision, polyopia, and difficulty refocusing the eyes. These symptoms can be further aggravated by improper lighting conditions (i.e. glare  or bright overhead lighting) or air moving past the eyes (e.g. overhead vents, direct air from a fan).
According to the National Institute of Occupational Safety and Health, computer vision syndrome affects some 90% of the people who spend three hours or more a day at a computer.
Dry eye is a major symptom that is targeted in the therapy of CVS. The use of over-the-counter artificial-tear solutions can reduce the effects of dry eye in CVS.
Asthenopic symptoms in the eye are responsible for much of the morbidity in CVS. Proper rest to the eye and its muscles is recommended to relieve the associated eye strain. Various catch-phrases have been used to spread awareness about giving rest to the eyes while working on computers. A routinely recommended approach is to consciously blink the eyes every now and then (this helps replenish the tear film) and to look out the window to a distant object or to the sky—doing so provides rest to the ciliary muscles. One of the catch phrases is the “20-20-20 rule”: every 20 mins, focus the eyes on an object 20 feet (6 meters) away for 20 seconds. This basically gives a convenient distance and timeframe for a person to follow the advice from the optometrist and ophthalmologist. Otherwise, the patient is advised to close his/her eyes (which has a similar effect) for 20 seconds, at least every half hour.
Decreased focusing capability is mitigated by wearing a small plus-powered (+1.00 to +1.50) over-the-counter pair of eyeglasses. Wearing these eyeglasses helps such patients regain their ability to focus on near objects. People who are engaged in other occupations—such as tailors engaged in embroidery—can experience similar symptoms and can be helped by these glasses. A Pacific University research study of 36 participants found significant differences in irritation or burning of the eyes, tearing, or watery eyes, dry eyes, and tired eyes, that were each improved by filtering lenses versus placebo lenses.