Coffee worshipers, rejoice! In addition to energy benefits from coffee, food scientists say you may have another health benefit from a cup of coffee a day: preventing deterioration of vision and possible blindness from retinal degeneration due to glaucoma, aging and diabetes.

Crude coffee, on average, has only 1 percent caffeine, but it contains 7 to 9 percent chlorogenic acid, a strong antioxidant that prevents retinal degeneration in mice, according to a Cornell study published in the Journal of Agricultural and Food Chemistry .

Retina is a thin layer of tissue on the back of the eye's back wall with millions of light-sensitive cells and other nerve cells that receive and organize visual information.

It is also one of the most metabolic-active tissues, which leads to high levels of oxygen and makes it susceptible to oxidative stress. Lack of oxygen and the production of free radicals leads to tissue damage and loss of vision.

The study is "important in understanding functional foods, so natural foods that provide beneficial health effects," said Chang Y. Lee, a professor of food sciences and senior author of the study.

"Coffee is the most popular beverage in the world, and we are realizing what benefit we can get from it."

Previous studies have shown that coffee also reduces the risk of chronic diseases such as Parkinson's, prostate cancer, diabetes, Alzheimer's, and age-related cognitive decline.