ergonomics is the science that studies how to adequate the relation of the human being to his environment, according to the official definition adopted by the council of the international ergonomics association (iea), in august 2000. one of its branches, physical ergonomics, is in charge to study the most suitable positions. according to different studies conducted in europe and in the united states , it is estimated that between 50% and 90% of the computer users suffer from ocular fatigue, red and dry eyes, eyelid tension, weeping, burning sensation, blurred vision, and difficulty to focus remote objects. the inappropriate body postures also produce muscular tension, headache, neck and back pain. that's why it is very important to adapt work to man and each man to his work. most of the risk factors are introduced in working activities without a previous study of its effect on health. generally, prevention norms are established once damage has been done, and many of them appear long after these effects are known. we made a documentary bibliographic review, where the importance of the precautions to bear in mind in relation to posture, in the visual and cardiovascular systems, as well as in the correction of these manifestations to prevent professional diseases were stressed. ergonomics and risk factors of occupational health should be periodically assessed at each working place. to this end, all those workers using the computer systematically should be checked up by professional nurses.