Andrew Leland was in his first year of high school when he realised there was something wrong with his sight. Climbing a hill one night on the outskirts of Santa FeThe capital of the US state of New Mexico., he kept losing the path, despite the bright moonlight: "At one point, I walked right into a pinon tree with prickly branches."

His mother took him to see a doctor, who diagnosedWhen a doctor declares that a patient has a condition or illness. a rare disease called retinitis pigmentosa. "As the disease progressed, the rod cells around the edges of my retina would die, followed by the cones," Leland writes in his book The Country of the Blind: A Memoir at the End of Sight. "My vision would contract, like looking through a paper-towel roll. 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 - "The white of the page took on a wince-inducing glare, and the words frosted over" - he finally accepted that blindness was inevitable.

Then he heard about a centre in DenverThe capital city of the US state of Colorado. where people stay for several months wearing blacked-out goggles and learning to live without sight. It teaches a method called "structured discovery", whereby students learn to take in their surroundings by feeling and hearing and work out where to go from there.

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.

The key, one expert told him, was to have faith in his own ability: "Until you get profoundly lost, and know it's within you to get unlost, you're not trained - until you know it's not an emergency, but a magnificent puzzle."

The centre was set up by the US National Federation for the Blind. It taught that blindness was "merely a characteristic, like hair colour". Students were encouraged to try activities like rock climbing and water skiing.

Leland, who still has some sight, spent a month at the centre. There he started to appreciate the new experiences that blindness gave him. He learnt to hear in a different way: when a baby was brought in on a visit, "The sounds that she made - cooing, laughing - cut through the room like washes of colour."

At the end of his stay there were two challenges. One was to cook a meal for 60 people, which he managed, though he burnt a finger.

The other involved being dropped in a mystery location in Denver and finding 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.