Pediatric exam foreshadows vision problems.
Eighteen years ago, researchers at the Massachusetts Institute of Technology began recruiting newborns for a study of how normal vision develops. The group used a retinoscope to detect visual defects, including myopia. People with myopia can see objects close at hand, but distant objects appear blurry To the investigators' surprise, many of the infants were myopic.
Those findings prompted the team to keep track of the infants, says Jane Gwiazda, a psychologist at M IT and one of the researchers. They have since taken nearly 8,000 vision measurements from more than 400 children.
The team discovered that nearsightedness improves dramatically during the first five years of life. That finding fits with the observation that very few children in kindergarten have vision problems.
However, the M IT data reveal that some children start showing signs of myopia between age 6 and 12. More significant, the children who had myopia as infants also had the highest risk of developing this problem later, Gwiazda says. She presented the results of the study at the Science Writers Seminar in Ophthalmology held this week in Universal City, Calif.
The findings suggest that a child's first eye exam ought to take place at least six months after birth but before age 1. The standard recommendation to have an eye exam at school age is unlikely to yield useful information about a child's future risk of myopia, she says.
Children with myopic parents have a greater chance of developing this visual problem, the study shows. When both parents were myopic, 42 percent of their children became nearsighted; if only one parent was nearsighted, the incidence of myopia in offspring dropped to 22.5 percent; and if neither parent suffered myopia, only 8 percent of their children were nearsighted, Gwiazda says.
Many researchers postulate that close-distance work, such as reading and writing, which increases when children enter school, may trigger symptoms of myopia. In fact, some ophthalmologists believe that society's reliance on computers and its penchant for television viewing have also contributed to the disorder. The link between close-distance work and myopia remains controversial, however, Gwiazda notes.
The study's findings raise the question of whether physicians can prevent nearsightedness in children at risk. Current efforts start well after school age, but the new results suggest that preventive measures could begin much earlier, perhaps in infancy.
In a related report, ophthalmologist Joseph M. Miller of the University of Arizona in Tucson stressed the need for early detection of amblyopia, another visual defect in children. A child with amblyopia, or lazy eye, has one eye that is misaligned. To prevent double vision, the brain ignores the image from the skewed eye. The result is that vision in the affected eye deteriorates, often to the point of legal blindness. At the seminar, Miller reported on a computerized method of image analysis that detects amblyopia in very young children.
Right now, there is no way to stave off nearsightedness, even if at-risk infants are identified, Gwiazda admits. She hopes that research into the cause of myopia will lead to preventive treatments for this common visual problem. By contrast, early diagnosis of amblyopia could lead to more timely treatment, Miller says. Prompt treatment, usually with an eye patch, can restore perfect or nearperfect vision in an affected child, he says.
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|Title Annotation:||research on myopia|
|Author:||Fackelmann, Kathy A.|
|Date:||May 1, 1993|
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