"Excessive computer use 'threat to eyesight'"
Watching a computer screen for nine or more hours a day might be linked to a progressive eye disease that can blind without treatment, researchers warned yesterday.
The risk of developing glaucoma this way was highest for those with short sight, they said in a study which provided more bad news for male office workers and professionals.
They were told by New York eye specialists last year that wearing a tightly knotted tie could make the condition more likely.
The potential dangers of the booming use of new technology in the office and at home were outlined by researchers at the Toho University school of medicine in Tokyo, Japan, in the Journal of Epidemiology. They tested 10,000 workers with an average age of 43 as part of a general medical check-up as well as collecting their histories of computer use and eye disease.
Just over 5% had visual field abnormalities and there appeared to be a significant link between these and heavy computer use among those with long or short sight. But detailed eye tests revealed that a third of these had suspected glaucoma, and this was more obvious in those with myopia.
A link with short sight has already been established for glaucoma, a disease in which fluid cannot flow out of the eye because meshwork in the coloured part, the iris, has become blocked. Pressure then builds up, threatening damage to nerve fibres in the back of the eye and the optic nerve.
But the added ingredient of heavy computer use, while long debated as a possible risk factor for short sight, has not been studied for glaucoma, according to David Wright, chief executive of the International Glaucoma Association (IGA), who said the researchers "have provided a fascinating study that needs to be followed up".
About 2% of people over 40 develop glaucoma, which if diagnosed early can usually be treated with eyedrops. "Anyone over 40 should have regular, routine and comprehensive eye tests," said Mr Wright.
There were comparatively few women in the Japanese study because men comprise most of the workforce there. The researchers also said it was difficult to establish exactly who might have had a family history of glaucoma because it often went undiagnosed for a long time.
They suggested, however, that the optic nerve in myopic eyes might be much more susceptible to computer stress. "Computer stress is reaching higher levels than has ever been experienced before. In the next decade, therefore, it might be important for public health professionals to show more concern about myopia and visual field abnormalities in heavy computer users."
The type of chronic glaucoma that was a concern in the Japanese study is the most prevalent in Caucasian and African-Caribbean populations.
Close blood relatives of people who have glaucoma are at far higher risk, and the IGA says such people should be tested from the age of 35, rather than 40. For African-Caribbeans, for whom the risk is four times as high as whites, or for those with diabetes, testing should be done even earlier.
If the condition is advanced, or drops fail to reduce eye pressure, surgery might be needed to make an extra drainage channel in the white of the eye. Alternatively, laser treatment might be used to improve the flow of fluid through the meshwork around the iris.
Posted on 4/9/2008 12:37:07 PM
