For those who have wondered over the years why Bono is rarely seen without some form of tinted or colored glasses, the latest issue of Rolling Stone sheds some light on the question.
As you can see, Bono is in the late stage of the disease called inkgoopyeye.
Though not life-threatening, this disease can result in the occasional joke or jab from a random person on the Internet.
Unfortunately, this issue of Rolling Stone does not clear up the reason(s) behind the ever-present stocking cap on the head of The Edge, a phenomenon which continues to baffle scientists and junior high school students.