May be caused by many different environmental and visual conditions. When working on a computer, the muscles of the inner eye may tighten. This tightness can cause eye irritation and produce symptoms such as fatigue, red eyes, eye pain, blurred vision, headache and double vision.
Blurred vision is a loss of sharpness of vision and the inability to see small details. Blurry vision is sometimes related to the inability of the eyes to steadily focus on a computer screen for a significant amount of time. Also, vision may be blurred by constantly changing focus, such as looking back and forth between the keyboard and the computer screen.
You may develop a headache after staring at a computer screen for a significant amount of time. The brightness and contrast of the monitor may produce an indirect glare that is hard on the eyes. Direct glare, light that shines directly into the eyes such as overhead lights and light from windows, can also cause eyestrain and headaches.
Dry eyes result from a lack of moisture in the eyes. Tears replenish moisture to the eye by way of blinking. Blinking is one of the fastest reflexes of the body. However, people tend to blink about half as much as normal when they are working on a computer.
Fatigue is another sign of computer vision syndrome. Looking at a computer screen with untreated vision problems can lead to eye and general fatigue. Overall fatigue from working too long at a computer and concentrating without blinking, combined with poor lighting, can result in vision problems.
Double vision, or diplopia, is the perception of two images from a single object. Staring at a computer screen for too long may cause double vision.
Neck &shoulder pain
Since the eyes lead the body, we may sit in awkward positions while at the computer to compensate for visual problems as they occur. Slumping or slouching can lead to neck and back pain. Also, if you wear glasses with a bifocal while at the computer, you may unknowingly be tilting your head in various ways in order to see the screen clearly, resulting in physical pain.
The symptoms’ descriptions are taken from the article “Recognize the Symptoms of Computer Vision Syndrome” written by Troy Bedinghaus, O.D. (vision.about.com)
Check how to prevent and reduce the symptoms in Protect & Treat section.