Staring at computers may cause glaucoma

Spending hours staring at a computer screen may raise the risk of glaucoma, a progressive eye disease that can lead to blindness, scientists believe.

Spending hours staring at a computer screen may raise the risk of glaucoma, a progressive eye disease that can lead to blindness, scientists believe.

The dramatic discovery contradicts years of advice which suggested that gazing at computers did not damage the optic nerve. Researchers aim to replicate the study to confirm the findings.

The results emerged from a study in Japan of 10,000 workers with an average age of 43. It found a statistical link between heavy computer use and eye problems that presage glaucoma. The problems were more common among staff with existing vision defects such as short-sight or long-sight.

The team warned that there could be a dramatic rise in the number of glaucoma cases, or patients showing the early signs, if action was not taken to check people who spend long time in front of screens and have existing eye conditions.

"Computer stress is reaching higher levels than have ever been experienced before," the team from the Toho University School of Medicine in Tokyo said. "In the next decade, therefore, it might be important for public health professionals to show more concern about myopia [short-sightedness] and visual field abnormalities in heavy computer users." Visual field abnormalities are distortions or gaps in the field of view.

"Myopic workers with a history of long-term computer using might have an increased risk of visual field abnormalities, possibly related to glaucoma," said Dr Masayuki Tatemichi, who led the team. The work was reported in the British Journal of Ophthalmology.

Glaucoma is more common in old age, and happens when the optic nerve in the eye is damaged, possibly by high pressure inside the eye. The causes are unknown, but potential risk factors include smoking and high blood pressure.

Opticians had discounted the possibility that computer use could be linked to glaucoma and several studies had suggested that there was no connection between intensive computer use and glaucoma. Although poor computer screens can cause eye strain, that was not believed to be a precursor to the problem.

For male office workers, the work is a second alarm bell over glaucoma; last year a study suggested wearing a tie too tightly could also lead to the disorder.

The investigation by the Toho University researchers found that 522, or 5.1 per cent, of the workers had "visual field abnormalities", which can be a precursor to the full-blown condition - which normally affects 0.74 per cent of the population. Further tests on the 522 subjects found that 165 (32 per cent) had suspected glaucoma.

The researchers also found a significant statistical link with heavy computer use among short-sighted workers. They suggested that the optic nerve in short-sighted people might have a structural condition that renders it more susceptible to computer stress than non-myopic eyes.