Los Angeles - Bono has had glaucoma for the last 20 years.
The U2 frontman is often seen sporting a pair of sunglasses when he appears in front of photographers, but the 54-year-old singer says he does this in order to protect his sensitive eyes.
Speaking on the Graham Norton show on Friday night, he said: "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'm going to be fine. You're not going to get this out of your head now. You're going to be saying, 'Ah, poor old Bono.'"
The condition is caused by a build up of pressure within the eye that if left untreated, can lead to blindness.
U2 released their latest album Songs of Innocence via iTunes last month and although it has received rave reviews, Bono recently apologized as some people complained it took up space and was an unnecessary automatic freebie.
Joking on Twitter Graham Norton took the mickey out of the whole situation:
"Normally when bands come on they're trying to flog an album, but everyone's got it already! - @GrahNort on @U2. #TheGNShow
— Graham Norton Show (@TheGNShow) October 17, 2014
Did you know the Apple symbol for 'Artist' on iTunes is Bono? Another revelation from tonight's #TheGNShow
— Graham Norton Show (@TheGNShow) October 17, 2014
ICYMI, this is what U2 looked like 30 years ago, without the addition of Bono's glasses and The Edge's beanie.
"I think this was during the great conditioner shortage in Ireland in 1980 @GrahNort on @U2's 1980s image #TheGNShow pic.twitter.com/9MX7Ucq51P
— Graham Norton Show (@TheGNShow) October 17, 2014