All displays - CRT and LC - harms eyes, though the latter are considered safe. It was established that harmful influence of monitors lie not in electromagnetic emanation but in the fact that people blinks less while working at computer.

Investigations of American scientists from Ohio State University proved certain peculiarities of eyesight determine harmful influence of displays. While working at computer user has to screw up his eyes in order to see details on screen or reduce brightness. This can lead to asthenopia and dryness of eyes. Therefore, LC-displays also harm our eyes.

The more person screws his eyes - the less he blinks. At maximum effort of eyesight the frequency of blinking reduces to 4 times per minute. This tendency is very dangerous because as a result of insufficient wetting of eyes user feels discomfort, "sand in eyes".

Researchers investigated reactions of volunteers who concentrated on small black spot at monitor. Results revealed that majority of users screw eyes while working on computer without realizing it. Attempt to focus twice reduces the frequency of blinking - 7 times per minute.

By words of scientists, problem can be solved by "smart" monitors, which tune brightness and contrast of image for concrete person.
sections: Nature & Health, Hi-Tech