You might want to reconsider that second or third cup of coffee;  Researchers have found a link between coffee and increased chances of developing Glaucoma - which can lead to blindness.

The study from Harvard University goes against the recent reports that touted the health benefits of drinking coffee.  It's believe in this case that it's the caffeine and not the coffee that might be the dangerous factor.  However, scientists are cautious about making assumptions.

"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.

More tests need to be done before the medical field starts to suggest people with histories of Glaucoma ward themselves off caffeine.

Coffee Might Raise Glaucoma Risk: Study - US News and World Report.