People who drink a cup of hot tea at least once a day are 74 per cent less likely to be diagnosed with glaucoma — a severe eye problem that can lead to permanent vision loss.
But coffee, iced tea and soft drinks don’t seem to make any difference, the researchers found.
The researchers, whose work is published in the British Journal of Ophthalmology, asked 10,000 people in the US about their diet and health, and 1,678 of them also had full eye tests.
The University of California team found a significant link between tea and glaucoma.
Glaucoma, one of the leading causes of blindness, causes fluid pressure to build up inside the eye, damaging the optic nerve.
The scientists believe the antioxidants and natural anti-inflammatory chemicals in tea may play a role in protecting against this process.
They wrote: “Further research is needed to establish the importance of these findings and whether hot tea consumption may play a role in the prevention of glaucoma.”
British scientists welcomed the findings.
Professor Chris Hammond of King’s College London, said: “These results are interesting and add to the increasing consensus that tea contains antioxidants and other compounds that are good for our health.
“Glaucoma becomes more common with age, and is a significant cause of blindness in the UK.
“However, as this study looked at many dietary factors and is only a snapshot taken at a single time point, further longer term studies in the UK and other populations are needed, to see if tea drinking really does protect us from glaucoma.”
But Dr Graham Wheeler, a medical statistician at University College London, said: “The authors did not explore how, biologically, this association might work, which means the results from this study say nothing about one thing causing another.
“Participants were not asked what type of tea they drank, or whether milk, sugar, or other additives were used.”
Dietitian Catherine Collins added: “Tea is a healthy drink, rich in antioxidant polyphenols such as tea catechins and other flavonoids. However, in this research, it wasn’t the type of tea or its strength that appeared protective, rather the temperature at which it was drunk.
“But don’t let that stop you having a cup of tea – it’s a healthy, sugar free drink which may also help protect against tooth decay.”