U2 lead singer Bono wears sunglasses because it forms a barrier between himself and his audience.
According to Contactmusic.com, Bono claims his eyes are sensitive to light and swell up if the glasses are removed. But, he also likes to maintain some distance from his fans.
He says: "There are many reasons for the glasses I sport. Some for privacy and other for medical reasons. I do like having one step of a remove, actually. I don't think when I am singing I hold anything back and I don't think when I am writing I hold anything back".
"But I think I am allowed to hold something back in this kind of a set-up. As honest a man as you are and as honest as I am trying to be, there is a natural insincerity in the set-up and I am trying to be much better at it. But just one step removed."