There’s a reason behind the lead singer of U2’s love for orange-tinted sunglasses, and it’s not just his rock-star attitude. Turns out, Bono has been living with glaucoma for the last 20 years, a health issue he recently disclosed on British TV, CNN reports.

Glaucoma is caused by a buildup of pressure in the eyes that, over decades, can damage cells at the center of the optic nerve, the cable at the back of the eye that connects and transmits what you see. At first the disease causes difficulties in peripheral vision, and it can eventually lead to total blindness. The illness is a leading cause of blindness among African Americans and Hispanics in the United States.

Bono made the announcement last week on UK celebrity Graham Norton’s evening talk show. He was flanked by the rest of his band, as well as actors Robert Downey Jr., Robert Duvall and Stephen Fry.

The 54-year-old singer decided to disclose after Norton showed a couple of the group’s early photos from back in the ’80s, in which Bono is, surprisingly, not wearing sunglasses. Norton then asked the rock star, “Do you ever take those off?”

The U2 frontman said yes, and that despite having glaucoma, he has excellent vision. But Bono’s eyesight is affected by some cloudiness and rings, common indicators of the disease. The good news? Glaucoma is treatable with medication or surgery.

For more information about Bono’s eye disease, click here.