Lots of research on the causes of EG is happening. The stated purpose of this study was to look at risk factors for developing it.
METHODOLOGY: Based out of Brigham and Women's Hospital in Boston, the researchers followed 78,977 women and 41,202 men, all initially without glaucoma who'd had eye examinations from the 1980s until 2008. They asked them all about their coffee (and other caffeine) habits, then compared them to their medical records if they reported a history of glaucoma, looking specifically for diagnoses of exfoliation glaucoma. They also counted diagnoses of "exfoliative glaucoma suspect." That included patients who had high pressures in their eyes, changes in their optic nerve, and/or visual field problems. They pooled the data from the cohorts via meta-analysis.
Note that they only measured regular coffee, not decaffeinated.
RESULTS: People who drank three or more cups of coffee every day were significantly more likely to have exfoliation glaucoma.
They didn't report on an association with actual vision loss.
The trend "did not robustly extend to
caffeinated product consumption generally."
CONCLUSION: Drinking a lot of coffee is associated with increased risk of developing exfoliation glaucoma, and thereby a risk of impaired vision and blindness.
IMPLICATION: This is a large, prospective study worth factoring into the increasingly expansive discussion on coffee's plusses and minuses. "Life without life's joys is living death." And then, buried in the paper was this little gem: "The highest caffeine consumers were somewhat less likely to have hypertension, diabetes, high cholesterol, and myocardial infarction."
Takeaway, get screened for glaucoma regularly, even if you've never had any coffee ever. There were 44.8 million people with open-angle glaucoma in the world in 2010, and by 2020 there will be 58.6 million. We can't jump to saying this glaucoma-coffee association is definitely causal and that no one should drink coffee. I'm actually drinking some very bad coffee right now. If, for the time, though, these findings promote glaucoma awareness and continued research on the tremendous amounts of coffee and caffeine we drink/eat/rub all over our bodies, it's useful and good.
The study, "The Relation between Caffeine and Coffee Consumption and Exfoliation Glaucoma or Glaucoma Suspect," is published in the journal Investigative Ophthalmology and Visual Science.