By 2050, researchers predict that about half of the world’s population will be nearsighted. This probably isn’t a coincidence, but instead may be a result of our environment and the way our eyes are adapting to the new tasks (and books, and screens) at hand, according to Dr. Viola Kanevsky, a past president of the New York State Optometric Association.
In addition to genetics, the reason so many of us start squinting trying to read a road sign may be because our eyes adapted to a more indoor, in-your-face environment while they were growing to their adult form and length.
This is opposed to a person with either “perfect” vision or someone who is farsighted, who’d be much better suited to spotting danger in the distance. It’s even possible there may have been more of them back in the day, compared to the smaller 5 to 10% proportion of far-sighters these days. (Age-related presbyopia, which gives you a farsighted effect because you can’t see up close, is actually a different condition.)
“We think, partially, that’s an adaptation to our environment,” Kanevsky said of the growing number of people who are developing nearsightedness, also called myopia. “The guy that survived was the guy who could see the tiger coming to eat him first.”
While we aren’t doing much tiger-chasing anymore, there are health risks associated with being farsighted or nearsighted — severely nearsighted, in particular. Here’s a closer look at what Kanevsky says it means to be nearsighted versus farsighted, how to slow the risk of nearsightedness in children and other ways our eyes may be reflecting the new world we live in.
How nearsightedness and farsightedness develop
There is a genetic influence to being either nearsighted or farsighted, aka hyperonic. Meaning, if one or both of your parents needs glasses, you have a greater chance of needing them yourself. For example, if one parent is nearsighted, their child would have roughly a 30% chance of also being nearsighted, Kanevsky said.
Anatomically, there are differences between a nearsighted and a farsighted eye. A nearsighted eye would typically be considered “longer” than a perfect eye, whereas a farsighted eye would be considered “shorter” than a typical eye.
Most babies are born slightly farsighted, Kanevsky says, until the eyes grow to their proper length. And for people who stay farsighted, vision correction may be needed to help them see close up and reduce the risk of eye strain and crossed eyes.
For those with myopia, it likely developed during childhood, as the eye kept growing and getting longer than what’s “normal.” While the progression from a little blurry to total blur might seem inevitable, it turns out it’s not. While nearsightedness is not reversible, being severely nearsighted is preventable for many people.
Your family history and genes affect your vision, but that’s only one piece of the puzzle.
The sweet spot of myopia
Catching myopia right at its beginning stages may help keep people in that relative sweet spot of having vision that’s arguably better-adapted to their environment, but not so myopic that they have an increased risk of eye diseases like glaucoma and retinal detachment, for which nearsighted people are already at higher risk.
This sweet spot maxes out at about 3 diopters of power, or a “negative three” prescription, according to Kanevsky.
To control myopia, there are a few treatments cleared by the US Food and Drug Administration for kids when their eyes are still developing and children are just slightly nearsighted. Parents and teachers are in a good position to spot this — squinting to read the blackboard, for example.
One of these methods is orthokeratology, which involves a hard lens kids put in at night and remove during the day. It works by temporarily flattening the cornea, which corrects vision for the duration of the day until you start the whole process over again the next night. This is a similar, nonsurgical method to lasik.
There are also specific, soft lenses for myopia control, according to Kanevsky, and are also approved by the FDA. She adds that while some eye doctors will prescribe myopia control contacts for adults, or for someone very nearsighted (i.e. over 3 diopters), she’s hesitant about flattening the cornea too much.
Another method is low-dose atropine drops used for myopia control, but only off-label, as the exact way they work isn’t clear enough yet to constitute FDA approval, Kanevsky says.
But all these methods in kids are about 50% effective at reducing myopia, Kanevsky says. Growing eyes typically change about a half step per year, she says — from -2 to -2.5 in one year, for example. With intervention, it could instead change to a -2.25.
“By intervening with these methods early on, we can slow that to a quarter step a year,” she added.
