It’s a hugely popular hot beverage that many of us kick-start the day with - but did you know that drinking too much of it could lead to glaucoma?
This common eye condition is where the optic nerve, which connects the eye to the brain, becomes damaged.
And if not dealt with swiftly and properly can ultimately lead to blindness.
So what's this drink we seriously need to monitor our intake of?
It's coffee – and it’s all down to the high levels of caffeine.
After water, coffee is the most popular drink in the world, with more than 400 billion cups consumed each year.
In Britain last year we spent around £1bn on it, consuming around two cups a day.
And there's nothing wrong with that - it's over-indulgence that's the problem.
Vision Direct says that regularly consuming more than the recommended amount of coffee per day could put you at risk of developing chronic conditions such as glaucoma.
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'Known to increase blood pressure'
The opticians explains: “Caffeinated drinks are known to increase blood pressure, as well as pressure in your eyes.
“Consistently high levels of eye pressure are known to cause glaucoma, so there could easily be a link between your coffee habit and one of the world’s leading causes of blindness.”
Furthermore, a study by Harvard Medical School found a link between drinking three or more cups of coffee and the risk of developing what’s known as ‘exfoliation glaucoma’.
“This happens when a build-up of fluid in the eyes turns up the pressure on the optic nerves,” Vision Direct says.
But the opticians was quick to point out that if you do choose to drink a lot of coffee this doesn’t necessarily mean you will definitely go on to develop glaucoma.
“For example, many participants of the study had a family history of glaucoma, which has been proven to be a key factor in developing the condition.
“It’s all about how your body handles caffeine - so it’s far from a one size fits all approach.
“These results are also based on regular overconsumption: more about consistently having three or more cups of coffee every day, rather than drinking an extra cup on a busy Monday.”
So how much is too much?
Healthline says the amount of caffeine in coffee can vary wildly, ranging from as little as 50mg per cup to a whopping 400mg.
To give you an idea, a small home-brewed cup could provide 50mg, while a 16oz Starbucks grande packs a considerable punch of 300mg a serving.
Healthline says as a general rule, it’s safe to assume that an average 8oz cup (240ml) gives a hit of around 100mg of caffeine.
Many experts agree that around 400mg of caffeine a day – that’s the equivalent of four cups (945ml) of coffee – is safe for most healthy adults.
Of course, drinking moderate amounts of caffeine isn’t only better for your eyes, it’s also linked to lower risks of liver disease, diabetes, dementia and even some types of cancer.
Vision Direct says: “Raw coffee beans contain chlorogenic acid (CGA), an antioxidant that helps to reduce blood pressure and improve circulation.
'Tends to develop slowly over many years'
Glaucoma is usually a condition that affects older adults in their 70s and 80s.
The NHS says: “It tends to develop slowly over many years and affects the edges of your vision (peripheral vision) first.
“For this reason, many people do not realise they have glaucoma, and it's often only picked up during a routine eye test.
“If you do notice any symptoms, they might include blurred vision, or seeing rainbow-coloured circles around bright lights.”
