AceShowbiz -

Bono reveals the real reason of his ever-present sunglasses, and turns out it's not because of a rock star affectation. During a visit to "The Graham Norton Show", the U2 frontman says he is suffering from glaucoma that makes his eyes sensitive to light. If not treated properly, it can lead to blindness.

When asked if he ever removes his shades, Bono says, "This is a good place to explain to people that I've had glaucoma for the last 20 years."

"I have good treatments and I am going to be fine," the vocalist assures fans, before jokingly adding, "Once you have this information, You're not going to get this out of your head now and you will be saying 'Ah, poor old blind Bono'."

The band was on the show as part of their press tour to promote their new album "Songs of Innocence". It was made available for free on iTunes and was automatically added to iPhone 6, sparking outrage from Apple customers.

"We wanted to do something fresh but it seems some people don't believe in Father Christmas," Bono addresses backlash. "All those people who were uninterested in U2 are now mad at U2. As far as we are concerned, it's an improvement."