The term computer vision syndrome (CVS) covers the myriad of visual disturbances that can occur when visually interacting with a computer display. According to Wendy Strouse Watt, O.D., those who spend in excess of 2 hours on the computer a day will eventually experience some symptoms of CVS. The chief problem with viewing computer screens for long periods of time is that human eyes are not able to handle this great of a visual demand. Human eyes have difficulty in focusing on the computer's pixel characters.
Symptoms
People who spend a significant amount of time working at a computer may find themselves experiencing one or more symptoms that are typical of computer vision syndrome. These include problems with the eyes directly such as soreness, burning, tiredness and dryness as well as vision difficulties including seeing blurred images, trouble focusing, double vision and increased sensitivity to light. In addition to these problems, a person with CVS may also have headaches and shoulder and neck pain.
Causes
Eyes focus well on printed material, especially print with defined edges and a distinct contrast between the words and the background they appear on. In contrast, human eyes struggle greatly with images on computer displays. This is because the pixel images are made up of many dots with ill-defined edges on a background that is the plane of the computer screen. The eyes will focus on this plane for a time, but they then "relax" to a place to the rear of the display called the "resting point of accommodation"(RPA), also referred to as dark focus.
Each person has a unique RPA, but it is almost always at a greater distance than when working at a computer terminal. Eye strain occurs as you relax to your RPA and then refocus on the computer screen. The eye muscles (ciliary body) are flexed constantly, resulting in fatigue and other problems with the eye and vision.
Self-Care
There are some measures you can take to reduce the effects of computer vision syndrome. Proper lighting, for example, can help alleviate eye strain. Reduce the glare and reflection off the computer screen by using low-intensity light bulbs and closing your drapes during the day. Another action you can take to combat CVS is to take frequent breaks by getting up from the computer for 10 or more minutes each hour.
Good posture as you work at the computer is important as well. Sit up straight, keep your feet parallel to the floor and adjust the height of your chair to make sure you are at a good eye level to the computer display. Your monitor should be placed directly facing you instead of at an angle. Sit 20 to 26 inches away from the screen as you work.
Warning
Do not wear bifocal glasses while working at the computer. These lenses force you to constantly tilt your head to focus on the screen and other objects. This frequent adjustment can cause eyestrain as well as neck and shoulder pain. Those who require bifocal glasses to see properly should consult an optometrist for suggestions regarding computer use.
Expert Insight
The development of special "computer glasses" can greatly reduce a person's propensity for developing CVS issues. These glasses are specifically designed to correct blurry vision and alleviate eyestrain, headaches and other computer vision syndrome problems. These glasses are recommended for both those who do not regularly require glasses and for those who do. Computer glasses must be prescribed by a vision specialist who accesses the patient's eyesight and decides which type of lenses are needed, taking into consideration the amount of time per day the person spends at the computer.
