Here’s a shocking stat for coffee drinkers: Researchers studied close to 80,000 women and 40,000 men over a 20-year-period and found that those who drank three or more cups of Joe a day had a 66 percent greater chance of developing exfoliation glaucoma—a condition in which a dandruff-like powder forms in your eye, increases pressure in your eyeball, damages the optic nerve, and eventually causes blindness.
But don’t worry about skipping your daily trips to Starbucks just yet, said Dr. Andrew Iwach, executive director of the Glaucoma Center of San Francisco, and a clinical correspondent with the American Academy of Ophthalmology.
The study authors suspect that caffeinated coffee may raise levels of the amino acid homocysteine, which damages blood vessels and other eye structures. The truth of the matter: As the researchers state themselves, the study is observational; they didn’t assign some people to drink coffee and some to lay off. Therefore, it can’t prove coffee causes glaucoma—only that there might be a link between the two, Dr. Iwach says. (Heard those other myths about your favorite a.m. staple? We debunk them in The Truth About Coffee.)
Though the connection may be real, doctors are a long way from listing java as a risk factor for blindness, Iwach said. “There are a whole list of glaucoma risk factors that we look for when a patient comes in for an exam, and eventually this might be on that list,” he said.
But for now, go ahead and order your venti Americano, and focus on factors that are proven to boost your odds for blindness: smoking, being hit in the eye, a family history of glaucoma, or taking corticosteroids, which are used to treat medical conditions like asthma, rashes, and tendon or joint problems. (Meanwhile, learn how to treat these other 5 Common Eye Injuries.)
Then take a moment to schedule a complete eye exam with an ophthalmologist. Begin with one in your 20s, even if you don’t think you have any risk factors. Your doc can assess your risk and check for physical signs of the disease, which often appear long before symptoms, Iwach said.