Myopia, or the need for corrected vision to focus or see objects at a distance, has become a lot more common in recent decades. , also known as nearsightedness, an epidemic.
Author
Andrew Herbert
Professor of Psychology, Visual Perception, Rochester Institute of Technology
Optometry researchers estimate that will need corrective lenses to offset myopia by 2050 if current rates continue – up from 23% in 2000 and .
The associated health care costs are huge. In the United States alone, spending on corrective lenses, eye tests and related expenses .
What explains the rapid growth in myopia?
who has studied visual perception and perceptual defects. To answer that question, first let’s examine what causes myopia – and what reduces it.
How myopia develops
While having two myopic parents does mean you’re more likely to be nearsighted, . That means the causes of myopia are more behavioral than genetic.
Optometrists have learned a great deal about the progression of myopia by . They do so by putting little helmets on baby chickens. Lenses on the face of the helmet cover the chicks’ eyes and are adjusted to affect how much they see.
Just like in humans, if visual input is distorted, a chick’s eyes grow too large, . And it’s progressive. Blur leads to eye growth, which causes more blur, which makes the eye grow even larger, and so on.
Two recent studies featuring extensive surveys of children and their parents provide strong support for the idea that an in myopia is that focusing on objects immediately in front of our eyes, whether a screen, a book or a drawing pad. The more time we spend focusing on something within arm’s length of our faces, dubbed “near work,” the greater the odds of having myopia.
So as much as and too much “screen time” for hurting our eyes, the truth is even activities as valuable as reading a good book can affect your eyesight.
Outside light keeps myopia at bay
Other research has shown that this unnatural eye growth can be interrupted by sunlight.
A 2022 study, for example, found that myopia rates for children who didn’t spend much time outdoors – say, once or twice a week – compared with those who were outside daily. At the same time, kids who spent more than three hours a day while not at school reading or looking at a screen close-up were four times more likely to have myopia than those who spent an hour or less doing so.
In another paper, from 2012, researchers that compared duration of time spent outdoors with myopia incidence. They also found that more time spent outdoors was associated with lower myopia incidence and progression. The odds of developing myopia dropped by 2% for each hour spent outside per week.
Other researchers have reported similar effects and argued for and changes in early-age schooling to reduce myopia prevalence.
What’s driving the epidemic
That still doesn’t explain why it’s on the rise so rapidly.
Globally, a and industrialization of countries in East Asia over the last 50 years. Around that time, young people began spending more time in classrooms reading and focusing on other objects very close to their eyes and less time outdoors.
This is also what researchers after World War II, when schooling was mandated for Indigenous people. Myopia rates for Inuit went from the single digits before the 1950s to upwards of 70% by the 1970s as all children began attending schools for the first time.
Countries in Western Europe, and Australia have shown in recent years but nothing approaching what has been observed recently in . The two main factors identified as leading to increased myopia are and other activities that require focusing on an object close to one’s eyes and a .
The surge in myopia cases will likely have its worst effects 40 or 50 years from now because for the young people being diagnosed with nearsightedness now to experience the most severe vision problems.
Treating myopia
Fortunately, just a few minutes a day with glasses or contact lenses that correct for blur , which is why early vision testing and vision correction are important to limit the development of myopia. Eye checks for children are mandatory in some countries, and , as well as .
People with with high myopia, however, have , such as retinal detachment, in which the retina pulls away from the the back of the eye. The chances of myopia-related increase by . A diopter is a unit of measurement used in eye prescriptions.
But there appear to be two sure-fire ways to offset or delay these effects: Spend less time focusing on objects close to your face, like books and smartphones, and spend more time outside in the bright, natural light. Given the first one is difficult advice to take in our modern age, the next best thing is taking frequent breaks – or perhaps spend more time reading and scrolling outside in the sun.
Andrew Herbert receives funding from NSF.
