For decades it’s been part of the image, a staple of Bono style; the famous sunglasses, worn as frequently indoors as outdoors. But tonight the U2 front man will admit on the Graham Norton Show that his constant wearing of the shades isn’t part of the rockstar image – but because he has suffered from a chronic eye condition for the past 20 years.

Speaking on the BBC ONE show, a pre-recorded show that will air this evening at 10.35pm, Bono explains that he suffers from the condition which can make eyes sensitive to light, but does not expect the condition to deteriorate, the Guardian reports.

Norton asked Bono if he ever takes the shades off, to which Bono replied: “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.”

“You’re not going to get this out of your head now and you will be saying, ‘Ah, poor old blind Bono.’”

US are on the show to promote the launch of their new album, ‘Songs of Innocence’, which endured a controversial release as it was gifted, free of charge, to users of iTunes; to the outrage of some.

The interview, and U2’s live performance is on BBC ONE tonight at 10.35pm.

Discussing the controversial method of releasing the music, Bono told Norton: “We wanted to do something fresh but it seems some people don’t believe in Father Christmas. All those people who were uninterested in U2 are now mad at U2. As far as we are concerned, it’s an improvement.”