With a growing body of evidence showing a correlation between time spend indoors and myopia, perhaps public health agencies can add blindness prevention to the list of reasons they encourage outdoor activity for children.
Myopia or “nearsightedness” happens when light focuses in front of the retina, instead of on it because the eyeball becomes elongated or football shaped. This results in blurry vision and difficulty seeing distant objects.
The main difficulty nearsighted individuals is the expense of corrective lenses and, optionally, laser surgery. High degrees of myopia (correction of -6.0 or greater), however, can result in conditions that lead to low vision, with retinal detachment the most prevalent problem. Those with high degree myopia are also at greater risk of glaucoma and develop cataracts earlier in life.
People have long recognized the correlation between time spent indoors and myopia, but the long time assumption was that it was associated with “near work.” In other words, I need glasses because I spent too much time with a book inches from my eyes.
More recently, researchers are finding that exposure to sunlight might be the key to healthy vision. In Seoul, an astonishing 95.6% of 19-year-old boys are near-sighted. In parts of China, up to 90% of teens and young adults are myopic.
20% of university students in East Asia have “high degree” myopia, and about half are expected to develop irreversible vision loss from retinal detachment.
The evidence is compelling enough that public health officials in Singapore now encourage outdoor play specifically to prevent vision loss.
Besides better vision, other public health benefits of encouraging outdoor play include better overall fitness, less obesity, stronger immune systems, more active imaginations, and less stress. Encourage your children to go outside and ride a bike.