Young Readers With This Gene Variant Are Far More Likely to Be Nearsighted

If you’ve spent hours with your nose pressed into a book, or are parent to any avid young readers, you may already have personal experience with myopia.  More commonly known as nearsightedness, this condition—which often leads to the need for prescription glasses and contact lenses to see past your own nose—has long been considered unpreventable. However, researchers at Columbia University Medical Center have isolated a variant of the gene for myopia, known as APLP2, which predicts a child’s likelihood of developing myopia specifically when the child spends at least an hour per day reading.

The study, published in PLOS Genetics, drew from an enormous longitudinal study of over 14,000 children in the UK.

Lead researcher Andrei Tkatchenko, assistant professor of ophthalmic sciences at Columbia, tells mental_floss, “We found that children who carried this specific variation of the gene were five times more likely to develop myopia if they read more than one hour per day compared to those kids who carried a normal version of the gene, or who read less than an hour per day.”

The form of reading doesn’t seem to matter, whether paper books, e-readers, tablets, smartphones, or computers, which he also calls “nearwork.”

AN "EPIDEMIC"—BUT POTENTIALLY TREATABLE

Tkatchenko has been working on the genetic component of myopia development since 2000, when he was a research fellow at Harvard and the test subjects were monkeys, whose eyes are very similar to ours. There he first isolated this particular gene variant, APLP2. He found a strong correlation between the degree of myopia and monkeys and level of the gene expression.

Though he and other researchers aren’t entirely sure yet how the gene variant causes myopia, they suspect that APLP2 proteins accumulate in the eye and cause one of two things to happen: either the eyeball becomes too long, or the cornea becomes too curved. Once myopia sets in, the eyeball and cornea will not shrink or change on their own.

However, Tkatchenko says, reducing gene expression of APLP2 may be able to protect against the development of myopia. “We showed for the first time that myopia is a treatable disease," he says. "We could theoretically influence expression of these genes and control it in children.”

If you think a little nearsightedness isn’t a big deal, consider the 14 percent increase in “myopes,” as the near-sighted are called, between 2004 and 2014 in the U.S.; today more than half the population is now nearsighted. In China, the situation is even worse. More than 80 percent of the population have myopia. “We are facing an epidemic of myopia. If this was an infectious disease we would quarantine people,” Tkatchenko says.

He accounts for an “environmental” rise in the levels of myopia, namely because children study much more. “If I compare my son to myself, he studies much, much more compared to the standard when I was growing up," Tkatchenko says. "Also, children use more computers, more portable devices, to access written information.”

KEEP READING, BUT GO OUTSIDE TOO—A LOT

While there is no medical treatment currently available to prevent myopia once it sets in, other than to wear corrective glasses, research has found one significant method of reducing the likelihood that even an APLP2 gene carrier will become myopic: playing outside. “Specifically scientists found that children spending at least two hours playing outdoors are much less likely to develop the disease compared to those who spend most of their time indoors reading, studying, playing video games or at the computer,” says Tkatchenko. He is encouraged by programs in China, where myopia is truly epidemic, to experiment with school schedules that give children as much outdoors time as possible in hopes of preventing the condition.

For the long term, he is putting his hopes on developing a genetic test to identify children prone to myopia early. Tkatchenko concludes, “If we can identify children who carry this myopic version of the gene, we could intervene and stop development of myopia, or at least slow the progression.”

In the video below, Tkatchenko talks about steps schools in China are taking to help book-loving children at risk of developing myopia by experimenting with school schedules to incorporate more outdoor time, and by building schools made of glass to increase student exposure to daylight.