As someone who drinks at least two cups of coffee a day, I was excited when I learned back in May that coffee drinkers may live longer than non-coffee drinkers. So imagine my disappointment when I read about a new study that links excessive coffee drinking to an increased risk of developing glaucoma. But before you throw out the coffee pot and switch to decaf, here's what you need to know:
A team of researchers at Brigham and Women's hospital in Boston studied 78,977 women and 41,202 men, all who had regular eye exams from the 1980s until 2008 and started off glaucoma-free. The researchers asked each subject about his or her coffee (and other caffeine) habits and compared what they were told to the subjects' medical records if they reported a history of glaucoma. Researchers looked specifically for cases of glaucoma in the medical records, as well as diagnoses of "exfoliative glaucoma suspect," or patients who had high pressure in their eyes, changes in their optic nerves, or visual field problems.
They found that those who drank three or more cups of regular coffee (they didn't look at decaffeinated java) a day were significantly more likely to experience exfoliation glaucoma. However, researchers didn't find this trend associated with other caffeined drinks such as soda, and they also didn't report on an association of actual vision loss, so it's impossible to say definitively that drinking coffee causes glaucoma.
Additionally, researchers found that coffee drinkers were less likely to have high cholesterol, hypertension, diabetes, and myocardial infarction. So don't worry too much just yet, though it may be prudent to get regular screenings for glaucoma, even if you don't drink that much coffee.