Andrew Leland was in his first year of high school when he realised there was something wrong with his sight. His mother took him to see a doctor, who diagnosedWhen a doctor declares that a patient has a condition or illness. a rare disease.

"As the disease progressed, my vision would contract, like looking through a paper-towel roll," Leland writes in his book The Country of the Blind. "By middle age, I'd be completely blind."

For years, he tried to pretend that it was not going to happen. But in his thirties the problem became too big to ignore. When reading became difficult, he realised he was definitely going blind.

Then he heard about a centre in DenverThe capital city of the US state of Colorado. where people learn to live without sight. Students wear blacked-out goggles and learn to take in their surroundings by feeling and hearing.

Warmth from the Sun, for instance, can tell you which direction you are facing. Traffic noise indicates where you are in relation to a road.

Leland, who still has some sight, started to appreciate the new experiences that blindness gave him. He learnt to hear in a different way and found that a baby's laughter "cut through the room like washes of colour."

At the end of his stay he was dropped in a mystery location in Denver. From there he had to find his way back to the centre. He was not allowed a phone and could only ask one question to one person along the way.

He succeeded by finding a bus stop and asking the bus driver how to get to the train station nearest the centre. He arrived back to cheers from his fellow students.

Two days later he flew home. When he reached his local airport, "I followed the sound of roller bags, feeling the carpet of the gate area give way to the concourse's linoleum. I was halfway to the escalators before I thought of using my eyes to look around for an exit sign. I already knew where I was going."

Yes: It makes you aware of the world in a completely new way, and encourages you to use the other senses - particularly hearing and feeling - which normally take second place to sight.

No: It makes everyday life incredibly difficult and ordinary activities like crossing a road very dangerous. It stops you from seeing beautiful sights and wonderful pictures and films. 

Or... A lot depends on when you become blind. Someone who is born without sight knows no other life. Someone who gradually goes blind has a very difficult adjustment to make.