Heavy computer use could be linked to glaucoma, especially among those who are short-sighted, fear researchers.
Glaucoma is caused by increased fluid pressure within the eye compressing the nerves at the back, which can lead to blindness if not treated.
The findings, published in the Journal of Epidemiology and Community Health, are based on 10,000 Japanese workers.
The authors and experts recommend more research, particularly because being short-sighted is a known glaucoma risk.
Dr Masayuki Tatemichi, from Toho University School of Medicine, and his colleagues tested the sight of workers in four different Japanese companies, employing over 5,000 people each.
The employees were asked to complete questionnaires about their computer use, both at home and at work, and any history of eye disease.
The researchers then divided the employees according to how much they used a computer, labelling them light, medium or heavy users.