Excessive computer use might be damaging to eyesight and could even lead to blindness, according to research.
In a study of 10,000 people carried out by Toho University medical school in Tokyo, Japan, office workers who spend all day looking at screens were found to have a one in 20 chance of risking eye problems, especially in people who are short-sighted.
Of these a third risk developing glaucoma which in turn can lead to blindness.
Dr Masayuki Tatemichi of Toho University Medical School, wrote in the Journal of Epidemiology and Community Health: "The optical nerve in short-sighted eyes might be more vulnerable to computer stress than it is in normal eyes."
While the exact cause of glaucoma is unknown, several factors such as smoking and high blood pressure are thought to be potential contributors.
Experts have pointed to the fact short-sightedness is more common in Japan and as such more research needs to be done to make a link between computers and eye damage in the UK.
David Wright, chief executive of the International Glaucoma Association, told BBC Online: "It will be important to follow this study with further research in other ethnic populations to establish the complete validity of this initial indication of a potential problem and also to address the ethnic risk factors should the evidence add to the Japanese report.