What is myopia and why is it becoming more common in children?

TLDR: Myopia, or nearsightedness, is a refractive condition in which the eye grows too long, causing distant objects to appear blurry, and its rapid global rise is driven by a combination of genetic risk, reduced outdoor time, and increased near-work demands.

What Is Myopia?

Myopia, commonly called nearsightedness, is a refractive error in which light entering the eye focuses in front of the retina rather than directly on it. The result is that distant objects appear blurry while close objects remain clear. In most cases, myopia develops because the eyeball grows too long from front to back — a process called axial elongation. As the eye lengthens, the focal point shifts forward, increasing the degree of nearsightedness.

Myopia is corrected with glasses or contact lenses that have minus-power (concave) lenses, which shift the focal point back onto the retina. While mild myopia causes only inconvenient blurry distance vision, high myopia — generally defined as a prescription of -6.00 diopters or more — is associated with a significantly increased risk of serious eye diseases including retinal detachment, glaucoma, myopic macular degeneration, and cataracts. This is why managing myopia progression in childhood is not simply about vision comfort — it is about reducing the risk of sight-threatening disease in adulthood.

The Global Myopia Epidemic

Myopia rates have increased dramatically over the past several decades, to a degree that researchers now describe it as a global epidemic. Studies from East Asian countries such as China, South Korea, Taiwan, and Singapore report myopia prevalence among young adults exceeding 80 to 90 percent — figures unimaginable just two generations ago. In the United States and Europe, prevalence has roughly doubled since the 1970s, with current estimates suggesting that approximately 40 to 50 percent of American young adults are myopic, up from around 25 percent in the 1970s.

By 2050, the World Health Organization and the Brien Holden Vision Institute project that nearly 5 billion people — roughly half the world's population — will be myopic, with 1 billion of those cases classified as high myopia. The scale of this trend has profound public health implications, given the associated risks of myopia-related eye disease.

Why Is Myopia Increasing?

The speed and scale of the myopia increase rules out a purely genetic explanation — genes don't change that quickly across populations. Research strongly points to environmental and lifestyle factors interacting with genetic susceptibility. Two factors have emerged as most significant: reduced time spent outdoors and increased time spent on near work.

Outdoor time appears to be protective against myopia development through a mechanism involving the neurotransmitter dopamine. Bright outdoor light (typically 10,000 to 100,000 lux, compared to 300 to 500 lux indoors) triggers the release of retinal dopamine, which inhibits axial elongation. Studies have found that children who spend 90 minutes or more per day outdoors are significantly less likely to develop myopia than those who stay mostly indoors. Randomized controlled trials in Taiwan and China that increased outdoor recess time in schools confirmed that this intervention meaningfully reduced the onset of new myopia cases.

Near work — reading, writing, and especially screen use — has also been implicated, though the relationship is more complex. Extended near work is thought to contribute to myopia through sustained accommodative demand and the short focal distances involved in screen and book use. The surge in screen time since the 2000s, combined with shifts in children's lifestyles toward indoor, sedentary activities, has created an environment that promotes myopia development and progression.

Genetics still plays a meaningful role — a child with two myopic parents has a significantly higher risk of developing myopia than one with no myopic parents. But genetics appears to determine susceptibility, while the environment determines whether and how severely that susceptibility is expressed.

When Does Myopia Start and Progress?

Myopia most commonly develops between ages 6 and 14, during the school years when near work demands increase and outdoor time often decreases. Children who develop myopia earlier — before age 9 — tend to progress more rapidly and reach higher final prescriptions, increasing their risk of high myopia. Progression typically slows in the late teen years as axial elongation naturally decelerates, but it can continue into the early 20s.

The rate of progression varies widely between individuals. Some children experience half a diopter of change per year; others progress much more rapidly. Regular monitoring every 6 months is important for any myopic child so that progression can be tracked and treated appropriately.

Why Myopia Control Matters

For decades, the standard approach to childhood myopia was to simply update the glasses prescription every year and hope it stabilized. We now know that this passive approach misses an important opportunity. Multiple evidence-based myopia control strategies — including orthokeratology, MiSight contact lenses, Stellest lenses, and atropine eye drops — have been shown to slow the rate of axial elongation by 40 to 70 percent compared to standard correction. This means that a child whose myopia might have reached -8.00 diopters could potentially stabilize at -4.00 or -5.00 diopters with proactive treatment — a clinically meaningful difference in their lifelong risk of eye disease.

If your child is myopic or has myopic parents, discussing myopia control options with a knowledgeable optometrist early — even at the first signs of distance blur — gives the best opportunity to influence the final outcome.

Ready to Protect Your Child's Vision?

At Lumen Vision, we specialize in pediatric optometry, vision therapy, and myopia control. Our team is passionate about catching vision problems early and giving every child the visual foundation they need to thrive. We proudly serve families across the region with comprehensive, compassionate eye care.

Call us at 701-404-9096, visit us online at www.lumen.vision, or schedule your child's appointment directly at scheduleyourexam.com/v3/index.php/6654.