We know we should feel concern for the blind, but almost as if in relief we are happy to mock the partially-sighted. Last Christmas, Disney's latest release in the United States, Mr Magoo, featured "America's favourite near-sighted cartoon character" in what was described as a live-action (as opposed to animated) comedy. Many of the "jokes" rested on Magoo's inability to see.
In his superb memoir Planet of the Blind, Stephen Kuusisto explains how a willingness to poke fun at blindness is nothing new. He describes how a group of blind men were once arrayed in a French village square, dressed as clowns and wearing dunces' caps. The joke was their discordant attempt to play musical instruments from scores propped up in front of them. The show lasted several weeks. The date was 1771, but this could well be a scene from Mr Magoo.
In other ways society is growing away from such careless cruelty, although not in time to help Kuusisto through his own tormented American youth. Born in 1955 practically blind, he was given no support at the mainstream school his mother insisted he was capable of attending. University meant books he could not decipher and reprimands about essays he was unable to do on time.
Picking up this general unwillingness to cope with near-blindness, he responded by denying his disability. The reward for this desperate policy was temporarily passing for "normal", only lost after 30 years, when he finally accepted a stick and dog. The punishments meanwhile were appalling - close encounters with death by traffic, other people's contempt at what looked like his clumsiness, and a state of misery caused by constant attempts to achieve the impossible.
It sounds grim, but Kuusisto is a well-read poet with a fine wit. His descriptions of near-blindness often contain a paradoxical beauty - what he sees is not blackness but vivid colours and fantastic shapes. The moment he realises he can rely upon his dog and "walk upright" is powerfully moving. His total honesty means that while we are not spared his worst moments, we also rejoice and believe in his successes.
His story has what can just about be described as a happy ending. After a period of lonely unemployment he became director of student services at a leading guide dog school in New York. His description of the dogs' training and his wonder at the other huge technical advances available to him sound a proper note of optimism - there is such a thing as progress after all.
What remains is the casual callousness occasionally picked up from passing strangers, some of them children. Mr Magoo has been granted a PG certificate in the US, in recognition that some parents may not like the idea of their children being encouraged to laugh at disability. Libraries with any money left could do even better by buying this modestly priced book. It is beautifully written, compulsively readable and a revelation about a condition that remains something of a secret.
Nicholas Tucker is a lecturer in psychology at the University of Sussex, Brighton