Coffee is one of the most consumed beverages in the world. Like many people, you probably start off your day with a cup of coffee. This drink is known to stimulate the brain and help keep you awake. Did you know that it can also affect your vision? Over-consumption of coffee can have negative impacts on your eye health, both short and long term.

What is the short-term affect of coffee on the eyes?
All things are good when consumed in moderation, and so is caffeine. An excessive consumption of coffee or caffeinated beverages can suddenly increase blood sugar levels, which can lead to blurred vision or spasms of the eyelid (jumping eye). Drinking too much caffeine can also cause a burning sensation and may make your eyes a little tingly. Dry eyes can also increase the risk of inflammation and might decrease your attention span. Despite the fact that these symptoms are not considered dangerous, they can cause discomfort and disrupt your daily activities.

What are the long-term effects of caffeine on vision?
According to a study by researchers at Brigham and Women's Hospital and, of Harvard Medical School, there is a direct correlation between people who drink three or more cups of coffee a day and their chance to develop glaucoma. This eye disease is characterized by high pressure on the optic nerve, which can diminish the visual field, and even cause blindness. According to the results of the study, drinking three or more cups of coffee per day would contribute to the accumulation of deposits inside the eyes, an ophthalmological syndrome called "exfoliation". This syndrome does not systematically cause glaucoma, but it does increase the risk of developing it. Family history is also known to have an impact on the risks of contracting glaucoma. The researchers concluded that consuming three cups of coffee (or more) per day increases the risk of exfoliation glaucoma by 66%, compared to people who do not drink caffeinated coffee.

However, as of now the research on the correlation between caffeine and glaucoma remains incomplete. Indeed, the researchers of Brigham and Women's Hospital and, of Harvard Medical School were the first to evaluate this association within the US population. Further research will have to be done within different populations to better validate the link between caffeine consumption and glaucoma. 

When consumed in reasonable quantities, coffee isn’t bad for your vision. However, short-term or long-term over-consumption can have negative consequences on your eye health. To learn more about the links between your lifestyle and your eyes, make an appointment with your IRIS optometrist for an eye exam!