Eye correction is seriously short sighted - 20 November 2002 - New Scientist

"Yet the only proof that it works comes from a study of just 33 Japanese children in 1965, and from studies on chicks in the 1990s. And these studies have since been attacked as lacking rigour or relevance. In their trial, O'Leary and his colleagues at the National University of Malaysia in Kuala Lumpur, undercorrected the sight of half the children and fully corrected the rest. Then they measured the length of the eyeball with ultrasound every six months. To their surprise, they found that the eyeball elongates faster when vision is undercorrected. As a result, the team reports in a paper that will appear in Vision Research, on average the vision of the 47 children with undercorrected myopia deteriorated more rapidly than those given full correction. Yet full correction has long been out of fashion. 'I had to go back to 1938 to find someone in the literature saying a full correction should be made,' O'Leary says. The explanation for his results, O'Leary speculates, is that the eye cannot tell whether the focal point is in front of the retina or behind it. It just grows backwards if the image is out of focus - which means that not wearing glasses might be even worse than undercorrection. 'Any blurred vision will make myopia worse,' he says."