Decreased exposure to outdoor light appears to be a major factor in rising rates of myopia in young people around the world.


By Jane E. Brody

Look and you shall see: A generation of the real-life nearsighted Mr. Magoos is growing up before your eyes. A largely unrecognized epidemic of nearsightedness, or myopia, is afflicting the eyes of children.

People with myopia can see close-up objects clearly, like the words on a page. But their distance vision is blurry, and correction with glasses or contact lenses is likely to be needed for activities like seeing the blackboard clearly, cycling, driving or recognizing faces down the block.

The growing incidence of myopia is related to changes in children’s behavior, especially how little time they spend outdoors, often staring at screens indoors instead of enjoying activities illuminated by daylight. Gone are the days when most children played outside between the end of the school day and suppertime. And the devastating pandemic of the past year may be making matters worse.

Susceptibility to myopia is determined by genetics and environment. Children with one or both nearsighted parents are more likely to become myopic. However, while genes take many centuries to change, the prevalence of myopia in the United States increased from 25 percent in the early 1970s to nearly 42 percent just three decades later. And the rise in myopia is not limited to highly developed countries. The World Health Organization estimates that half the world’s population may be myopic by 2050.

Given that genes don’t change that quickly, environmental factors, especially children’s decreased exposure to outdoor light, are the likely cause of this rise in myopia, experts believe. Consider, for example, factors that keep modern children indoors: an emphasis on academic studies and their accompanying homework, the irresistible attraction of electronic devices and safety concerns that demand adult supervision during outdoor play. All of these things drastically limit the time youngsters now spend outside in daylight, to the likely detriment of the clarity of their distance vision.

Recent research suggests that months of Covid-induced confinement may be hastening myopia’s silent progression among young children. A Canadian study that examined children’s physical activity, outdoor time, screen time and social media use during the Covid lockdown in early 2020 found that 8-year-olds spent an average of more than five hours a day on screens for leisure, in addition to screen time needed for schoolwork.

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