Nearsightedness, or myopia, is largely preventable in children and can be slowed significantly once it starts. The most effective single habit is spending at least two hours outdoors each day, which reduces the risk of developing myopia by 15% to 24%. Beyond that, a combination of screen time management, specialized lenses, and eye drops can keep mild myopia from progressing into the kind of severe nearsightedness that raises the risk of serious eye diseases later in life.
Globally, myopia rates are climbing fast. By 2050, an estimated 740 million children and adolescents will be nearsighted, up from roughly one in three today to nearly 40% of the youth population. Much of this increase is driven by lifestyle shifts: more time indoors, more close-up screen work, and less natural light exposure during the years when eyes are still growing.
Why Eyes Become Nearsighted
Myopia happens when the eyeball grows too long from front to back. In a normally shaped eye, light entering through the lens focuses directly on the retina at the back. In a myopic eye, light converges in front of the retina instead, making distant objects blurry while close-up vision stays clear.
The retina plays an active role in this process. It essentially sends “grow” or “stop” signals to the outer wall of the eye depending on where incoming light is landing. When a child spends most of their time focused on nearby objects, the principal image plane consistently falls behind the retina, and the eye responds by elongating. Once the eye has grown longer, the change is permanent. Glasses or contacts can correct the blurry vision, but they don’t reverse the structural change.
This is why prevention matters so much during childhood and adolescence, when the eye is still physically growing. Most myopia develops between ages 6 and 14, and progression typically slows in the late teens or early twenties as overall body growth tapers off.
Genetics Set the Baseline Risk
Family history is the strongest predictor. Children with two nearsighted parents are five to seven times more likely to develop myopia than children whose parents have normal vision. Having one myopic parent raises the odds by roughly 45% to 50%. These numbers come from a large cross-sectional study of children aged 6 to 18 in China, and they align with findings from populations worldwide.
Genetics aren’t destiny, though. The rapid increase in myopia rates over the past few decades is far too fast to be explained by genetic changes alone. Environment and behavior are the levers you can actually pull, and they make a measurable difference even in children with high genetic risk.
Outdoor Time Is the Strongest Protector
The single most well-supported strategy for preventing myopia is simple: get children outside. A 2022 analysis published in the journal Ophthalmology found that 120 to 150 minutes of daily outdoor exposure at bright daylight levels significantly reduced new myopia cases. The protective effect appears to come from the intensity of natural light itself, not from physical activity. Bright outdoor light stimulates the release of a neurotransmitter in the retina that helps regulate eye growth and prevents the eyeball from elongating too much.
Indoor lighting, even in a well-lit room, is typically 50 to 100 times dimmer than outdoor daylight. This difference matters. Studies in animal models consistently show that higher light intensity sends a “stop growing” signal to the eye. Overcast days still provide enough brightness to count, so outdoor time doesn’t need to mean direct sunshine.
For practical purposes, aim for at least two hours outside every day. Recess, walking to school, outdoor sports, and unstructured play all count. Splitting the time into multiple shorter periods works just as well as a single block.
Managing Screen Time and Close Work
Prolonged close-up work, whether on a screen, a book, or a tablet, creates the kind of visual environment that promotes eye elongation. The retina processes near visual scenes differently than distant ones. Close-up viewing places uneven focusing demands across the retinal surface, potentially creating peripheral blur patterns that act as a growth signal.
The commonly cited 20-20-20 rule suggests taking a 20-second break every 20 minutes to look at something 20 feet away. While this is a reasonable starting point, animal research suggests that the break probably needs to be longer. Studies in lab models indicate that looking at distant objects for at least 5 minutes every hour is more likely to meaningfully counteract the growth signals from sustained near work.
The World Health Organization recommends no screen time at all for children under one year old. For children aged one to two, screen time should ideally stay at zero, and no more than one hour for two-year-olds. Children aged three to four should also cap sedentary screen time at one hour per day, with less being better. These guidelines were designed with overall development in mind, but they align well with what vision researchers recommend for eye health.
Specialized Lenses That Slow Progression
If a child is already nearsighted, several optical tools can slow further progression. These don’t simply correct blurry vision the way standard glasses do. They actively change how light hits the peripheral retina, reducing the “keep growing” signal.
- Orthokeratology (Ortho-K): Rigid contact lenses worn overnight that gently reshape the cornea. Children wake up with clear vision and wear no correction during the day. Studies show Ortho-K slows the lengthening of the eye by 25% to 79% compared to regular glasses, with most results clustering around 40% to 50% reduction.
- Defocus-incorporated spectacle lenses: These look like regular glasses but have tiny segments built into the lens that create a specific blur pattern in peripheral vision. Over two years, one widely studied design slowed eye elongation by 62% compared to standard single-vision lenses.
- Peripheral defocus contact lenses: Soft daily-wear contacts designed with similar peripheral blur principles. These are typically prescribed for children between ages 6 and 12.
The key with all of these approaches is starting early. The American Academy of Ophthalmology notes that myopia control interventions are used in children as young as five or six, when eye growth is most rapid and there is the most progression left to prevent. Waiting until a teenager’s prescription stabilizes means the window for slowing growth has already closed.
Low-Dose Eye Drops
Low-dose atropine eye drops are one of the most studied pharmaceutical options for slowing myopia. Atropine at full strength has been used in eye exams for decades to dilate the pupil, but at very low concentrations (typically 0.01% to 0.05%) it appears to slow eye elongation with minimal side effects. The drops are used once daily, usually at bedtime, in children between ages 5 and 18.
The exact mechanism is still debated, but atropine likely acts directly on receptors in the retina and the outer wall of the eye, dampening the growth signals that drive elongation. At low doses, most children don’t experience the light sensitivity or blurred near vision that higher-strength atropine causes. Some children do see a rebound in myopia progression after stopping the drops, so treatment duration and tapering schedules are decisions best made with an eye care provider who specializes in myopia management.
Red Light Therapy: A Newer Approach
Repeated low-level red light therapy is a more recent addition to the myopia toolkit. Children look into a device that delivers dim red light (at a wavelength of about 650 nanometers) for three minutes, twice a day. The treatment appears to increase blood flow to a layer of tissue behind the retina called the choroid, thickening it and counteracting the elongation process.
In a 2023 study, children in the control group saw their eyes lengthen by 0.27 mm over six months, a typical rate of myopia progression. Children receiving red light therapy showed almost no change in eye length, and at the highest treatment power, eyes actually shortened slightly. These results are striking, but the technology is still relatively new and not yet widely available outside of clinical research settings in Asia.
Combining Strategies for the Best Results
No single intervention works perfectly on its own. The most effective approach combines outdoor time with one or more clinical tools. A child who spends two hours outside daily, follows reasonable screen time limits, and wears myopia-control lenses will likely see substantially less progression than a child using any one strategy alone.
For children who haven’t yet developed myopia, especially those with nearsighted parents, the priority is maximizing outdoor time and limiting sustained near work. For children already showing early signs of myopia, adding optical or pharmaceutical interventions early gives the best chance of keeping their prescription from climbing into the ranges associated with later complications like retinal detachment, glaucoma, and macular degeneration. The earlier you start, the more total eye growth you can prevent.