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Catch 'em young Jonathan Beard, New York WHOLE CLASSES COULD BE TESTED for colour-blindness in a few minutes using a cheap new test, paving the way for the routine screening of every schoolchild. Teachers could then help colour-blind pupils with any problems caused by their condition, say ophthalmologists in Wisconsin. The pencil-and-paper exercise, developed by Jay and Maureen Neitz of the Medical College of Wisconsin in Milwaukee, allows a teacher to test an entire class in just 10 minutes. The one-page handout contains eight plates, each with a geometric shape visible to children with normal vision. Children are asked to trace the outline of the shapes that they can see. Some of the shapes will be invisible to those with any of the three types of colour-blindness. "A teacher can score the tests in a matter of minutes," says Maureen Neitz. The materials are cheap because the handouts can be printed on an ordinary colour laser printer. The researchers tried out their test on 5000 children between 4 and 12 years old. For comparison, they also tested the children with a traditional colour-blindness test known as the Ishihara test, which can take longer to administer. False positives--where a child is wrongly diagnosed as colour-blind by making an error in the test--were no more common than for other tests. The new test was also just as sensitive as its predecessors. "No child who passed our test failed standard colour- vision tests," says Neitz. If colour-blindness is overlooked, children can be misdiagnosed with educational problems, according to Neitz. "More and more material, such as maps and charts, is colour-coded as cheap colour printers become widespread, and this particularly affects the youngest children," she says. Neitz cites the example of her severely colour-blind brother, who was described as unwilling and inattentive at school because he was unable to colour pictures according to teachers' instructions. If colour-blind children were identified at an early age, says Neitz, counselling could steer them away from careers that demand normal colour vision, such as pilots or the police. But Robert Massof, a researcher at the Lions Vision Research and Rehabilitation Center at Johns Hopkins University in Baltimore, is sceptical about the introduction of a new form of routine screening. "Valid and reliable colour-vision screening tests are nearly a century old and are routinely used," he says. "Mass screening of colour vision probably is not a major priority." However, Massof admits that education issues for children with colour-vision defects are important.
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