Study says drinking coffee increases risk of glaucoma

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A study has shown there is a big increase in risk for a certain type of glaucoma if one drinks 3 or more cups of coffee a day. My problem with the reports of the study is that there is no definition of what a cup of coffee is; that is how large, how strong, etc. Some reports have said that caffeine from other sources doesn't seem to have the same effect. I drink about two cups of coffee a day according to my filling my cup twice and drinking it and it is not that big a cup, not some large mug or something, but the level on the coffee pot reads almost 4 cups when I put in enough water to get my 2 cups. Also, I like my coffee fairly weak, Starbucks is way too strong for me. People have accused my coffee of just being colored water. Here is an example of a report on the study and no where is cup size or coffee strength mentioned: People who drink at least three cups of coffee a day might be increasing their risk of developing glaucoma, which can lead to vision loss or blindness, according to Harvard University researchers. Specifically, caffeinated coffee appears to be associated with a type of glaucoma called exfoliation glaucoma, which is characterized by tiny fibers peeling from the eye's lens that can cause a pressure build-up, the researchers said. "While caffeinated coffee has several health benefits, drinking three or more cups of caffeinated coffee was found to be associated with increased risk of developing exfoliation glaucoma, particularly among those with a family history of glaucoma," said lead researcher Jae Hee Kang, assistant professor of medicine at the Channing Division of Network Medicine at Brigham and Women's Hospital in Boston. The increased risk was on the order of 66 percent, Kang said. Since this is the first study to link caffeinated coffee and exfoliation glaucoma in a U.S.-based population, and because it is an association study and not a clinical trial, the results need to be confirmed through more studies, she added. "If confirmed," she said, "those at risk of exfoliation glaucoma particularly those with a family history of glaucoma would be recommended to limit their intake [of coffee] to less than three cups per day." The report was published Oct. 3 in the journal Investigative Ophthalmology & Visual Science. For the study, Kang's team analyzed data on almost 79,000 women who were part of the Nurses' Health Study and more than 41,000 men who took part in the Health Professionals Follow-up Study. None of these people had glaucoma and all said they had undergone eye exams from 1980 to 2008. In addition, the researchers used questionnaires to find out how much coffee they drank and also reviewed their medical records to find evidence of exfoliation glaucoma.