Screen-saver features help prevent this. Turning off the VDT when not in use is also helpful. A VDT or monitor with a deteriorated image should be replaced. Color Various opinions have been put forth as to what color and type screens are best for long-term viewing. This may actually be a personal preference item.
Color monitors offer the advantage of variety and selectability over monochrome devices.
Certain color combinations are obviously distracting and will cause eye strain. Good contrast and image resolution are important no matter what color. Screen Maintenance Cleanliness of the screen is important. Smudges, dust, scratches and so forth, cause the eye to attempt to focus in two planes simultaneously, causing strain. This is particularly noticeable if a glare filter is used over the front of the screen, and it is blemished.