This study was done on mice, but it would be great if it also holds true for human eyes. Another benefit from daily drinking of coffee! From Science Daily:
A cup of coffee a day may keep retinal damage away, study shows
Aside from java's energy jolt, food scientists say you may reap another health benefit from a daily cup of joe: prevention of deteriorating eyesight and possible blindness from retinal degeneration due to glaucoma, aging and diabetes.
Raw coffee is, on average, just 1 percent caffeine, but it contains 7 to 9 percent chlorogenic acid (CLA), a strong antioxidant that prevents retinal degeneration in mice, according to a Cornell study published in theJournal of Agricultural and Food Chemistry (December 2013).
The retina is a thin tissue layer on the inside, back wall of the eye with millions of light-sensitive cells and other nerve cells that receive and organize visual information. It is also one of the most metabolically active tissues, demanding high levels of oxygen and making it prone to oxidative stress. The lack of oxygen and production of free radicals leads to tissue damage and loss of sight.
In the study, mice eyes were treated with nitric oxide, which creates oxidative stress and free radicals, leading to retinal degeneration, but mice pretreated with CLA developed no retinal damage.
Previous studies have shown that coffee also cuts the risk of such chronic diseases as Parkinson's, prostate cancer, diabetes, Alzheimer's and age-related cognitive declines.