Eye Strain Eye strain can be a problem for people who do close up work, read a lot, or spend extended hours watching television or working on a computer. The eyes are designed to shift focus between objects that are close and those that are far away. Therefore, prolonged focusing on a single object can cause eye strain. Reading or doing close work in poor light for long periods of time forces the eyes to focus under difficult conditions, which can also cause eye strain.
Glare is a similar problem.
The contrast between the image you are looking at and its background is reduced by the reflected light, making it harder for the brain to interpret the image. Facial and eye muscles tighten as the eye unconsciously strains to send a clear signal to the brain. It had been thought for some time that radiation emitted by video display terminals or VDT's, including computers and televisions, might be harmful to the eyes and cause eye strain. However, many studies have shown that the tiny amount of radiation emitted by VDT's does not cause eye damage or eye strain, even after a life-time of exposure. Having eye strain does not mean you should stop using your eyes or that permanent damage will result.