Do you know why outdoor activity protects children from myopia?

Prof. Know Why answers for your general knowledge and awareness on: Do you know why outdoor activity protects children from myopia?

We all know that the more children are allowed to play outdoor sports, the better it is for their health in the growing days. But a recent study found that time spent outdoors even protects children against myopia.

The study has suggested that time spent in the open appears to protect children from near-sightedness, adding a new factor for a common condition that has long been blamed on extensive reading or genes.

Researchers at the University of Sydney, Australia, believe the intensity of outdoor light may be an important, but till now unrecognized, factor that influences the development of myopia, which usually begins during school years.

“Increasing outdoor activity may be a way to counter factors that might be contributing to myopia,” said Kathryn Rose, an ophthalmologist who led the study that involved more than 4,000 schoolchildren in Australia. It was published last week in the journal Ophthalmology.

The researchers found that 12-year-olds with the highest outdoor activity had the lowest rates of myopia, independent of the amount of reading or other near work they did. Myopia was most common in children with low levels of outdoor activity and high near work.

Long hours of indoor playtime or sports had no effect on myopia levels. “It appears to be the effect of intense light,” Rose said.

Myopic eyes are mildly elongated, front to back. The scientists believe that in response to light, the retina releases a chemical called dopamine and prevents eye elongation. The pupils also constrict in intense light, increasing the distance at which objects can be seen.

Near-sightedness has long been attributed to genetics. Children with parents who have myopia are at risk. “But we still can’t say whether it’s the effect of genes or whether the parents create an environment that promotes myopia,” Rose said.

“What has held out over the years is that children with strong scholastic achievements tend to have myopia. Our new study shows that children who do a lot of schoolwork and spend time outdoors appear protected.”

Independent studies in the US and Singapore appear to support these findings, she said.

The researchers have recommended more studies to try and establish the connection more firmly, and explore the mechanism of how exposure to daylight by means of outdoor activity, can prevent myopia.

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