NME reports that singer-songwriter Julian Lennon, son of John, addressed Bono's eye condition to the Irish Daily Star saying: "Bono actually has a condition with his eyes. I don't know the exact issue but the brightness of the sun hurts them and it's a deteriorating issue."
Bono has spoken about his eye-sight in the past saying he has to be careful when being photographed by fans and paparazzi, according to the Sunday Times.
"I have very sensitive eyes to light. If somebody takes a photograph, I will see the flash for the rest of the day. My right eye swells up."
Lennon says Bono has turned his eye condition into a trademark style.
"It's part of his image," Lennon says. "In some senses it was lucky but not really of course. Maybe it's part of his process now and without the image he can't be Bono."