U2's Frontman Bono
Bono has suffered very serious injuries in a bicycle accident. REUTERS/Mark Wessels

The mystery behind the permanent fixture of tinted sunglasses on the rock star's eyes has been unveiled. Irish singer Bono has revealed the reason for his fixation towards the sunglasses. Contrary to popular belief that such eyewear is his fashion obsession, he shared that he suffers from glaucoma.

"I have glaucoma for the last 20 years," told the 54-year-old musician and businessman. He declared the same on his appearance on 'The Graham Norton Show' with the rest of the band members. The revelations came as Norton shared a couple of the group's early photo from the 1980s, in which Bono was without any glasses.

The change was quite evident, which triggered the discussion about his fixation. He further explained after the surprising declaration that although he has fine vision, he started seeing cloudiness around the objects. This led to the diagnosis. The show will air tonight on BBC1.

Glaucoma develops when the fluid produced by the eye cannot drain properly, sometimes creating misty or watery eyes. If left untreated, the condition can lead to permanent blindness. It is a chronic disease and proper lifelong treatment is required by an ophthalmologist.

"I have good treatments, and I am going to be fine," said the front man of the Dublin-based rock band U2. In an earlier instance in 2005, Bono hinted to some medical condition in his eyes as the reason behind his love for sunglasses. He specified that his eyes get swell if he is not wearing his glasses and somebody uses a flash camera to take his snaps, as told by The Independent.

The band's latest album 'Song of Innocence' was released last month, which reaped its own share of controversy. Apple announced that it will be giving digital copy of the album to all the 500 million iTunes users at the unveiling event of iPhone6, iPhone 6 Plus and Apple Watch.

Instead of simply making it available, Apple went a step ahead and automatically sent it to active iTunes accounts, which automatically downloaded it to the aforementioned devices. This was not taken very well by many iPhone users and they found the act invasive, as reported by CNN.

The mentioned show will air tonight. Catch the exclusive spoiler footage from the show: