This can cause the focusing muscles of the eye to cramp, making it hard to focus on objects at different distances when you look away from the screen. As they stare, many computer users forget to blink, drying out their eyes. Reflections and glare from the screen can lead to tired, aching eyes. Glare usually comes from sunlight or office lighting that's too bright. In certain conditions, even light-colored clothing can cause an annoying reflection off the screen.
Computer screens are wonderful magnets for dust.
The film of dust that builds up on the screen blurs the image and makes your eyes work harder as they try to resolve the blur. Keep your computer screen free of dust. Try adjusting the lighting around your work area to minimize reflection and glare. If dimming the lighting isn't workable, use an anti-glare filter. Adjust the position of your computer screen.