U2's Bono, glaucoma and the need for regular eye tests

Bono, the U2 frontman, has revealed that he wears dark glasses all the time because he suffers from glaucoma. The star said he has had the condition - a build-up of pressure in the eyeball, which can damage the optic nerve and lead to blindness if not treated - for around two decades.

Many had assumed his ever-present sunglasses - even indoors - were a rock star affectation, but he explained during a recording of the Graham Norton Show for BBC One that they are to help with his vision problem.

Presenter Norton asked whether or not the singer ever removes his shades, 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."

He added: "You're not going to get this out of your head now and you will be saying 'Ah, poor old blind Bono'."

Glaucoma can make the eyes more sensitive to light, causing sufferers to use dark glasses to alleviate difficulties.  It is more usual in people whose parents have had it and those deemed 'at risk' are given free eye tests every year after the age of 40.

However, as Bono himself has demonstrated, the condition can occur much earlier than people expect (even in the 20's).  More worrying, there are no physical indications such as pain or discomfort.  Usually the only way of knowing you have it is to have an eye test...or when the condition itself starts robbing you of your eyesight.

If caught early, the condition can be easily treated with regular eye drops.  However, once progressed the damage caused can not be repaired and blindness can result.