Squinting to read the board, holding the screen closer and closer to the face, complaining of a headache at the end of the school day: this is how myopia in children, also called nearsightedness, can give its first sign. It is also becoming more common, with an estimate cited by the Brazilian Society of Pediatric Ophthalmology (SBOP) of half the world's population being nearsighted by 2050.
The good news comes from a place every Pathfinder knows well: the outdoors. This guide gathers what science has confirmed about outdoor time, with no promise of a cure and with sunscreen in the backpack.
What is myopia in children and why is it increasing?
Myopia, or nearsightedness, is difficulty seeing far away. According to the American Academy of Ophthalmology (AAO), it happens when the eye is longer than normal from front to back, or when the cornea is curved too steeply, so light comes to a focus in front of the retina. The details are in how the human eye works on the inside.
The AAO notes that myopia is usually found between ages 8 and 12 and can increase during the adolescent growth spurt. The technical note from the SBOP, written with the Brazilian Council of Ophthalmology (CBO) and the Brazilian Society of Pediatrics (SBP), warns that myopia is starting earlier, progressing faster and bringing more serious complications, some of which can lead to blindness.
In Brazil, the CBO Miopia report, presented in August 2025 at the 69th Brazilian Congress of Ophthalmology in Curitiba, found that 7.6% of children and teenagers aged 3 to 18 are nearsighted, according to Agência Brasil, the country's public news agency. The SBOP explains that myopia combines genetics and environment, with two major environmental risks: overusing near vision and spending little time outdoors in childhood. According to the CBO, children of nearsighted parents are up to five times more likely to develop the condition.
During the pandemic, 70% of the 295 ophthalmologists surveyed by the CBO in 2021 noticed myopia progressing in children, according to the SBP.
| Where | Myopia prevalence |
|---|---|
| Brazil, national average | 7.6% |
| Brazil, urban areas | 20.4% |
| Brazil, rural quilombola (Afro-Brazilian) communities | 1.06% |
| Latin America | 8.61% |
| Singapore | 66% |
| South Korea | 69% |
| China | 87.7% |
CBO Miopia report (Brazilian Council of Ophthalmology, 2025), according to Agência Brasil. The national average covers ages 3 to 18; the Asian figures come from studies with other groups and ages.
Does outdoor time protect against myopia?
For keeping myopia from starting, yes. When it launched its first World Report on Vision in 2019, the World Health Organization (WHO) linked the rise in myopia to more time indoors and more near-work activities, and stated that more time outdoors may reduce the risk.
In Guangzhou, China, a 2015 trial published in JAMA followed 1,903 first graders. In schools that added a daily 40-minute outdoor class, 30.4% of the children who were not yet nearsighted developed myopia over three years, compared with 39.5% in schools that kept their normal routine.
In Taiwan, a 2018 trial in the journal Ophthalmology, with 693 first graders, encouraged some of them to spend up to 11 hours a week outdoors during recess. Within one year, that group had a 54% lower risk of fast myopia progression, and the authors concluded that lower light levels for longer periods, such as under trees, may also work.
A 2022 review of reviews in the journal Ophthalmic and Physiological Optics pooled 47 studies and 63,920 participants. More time outdoors was consistently linked to fewer new cases of myopia. In participants who were already nearsighted, the slowdown in prescription change was between 0.13 and 0.17 diopters per year, which is not clinically meaningful, and the authors urge caution because of the quality of the reviews.
Why does outdoor light make a difference, even in the shade?
The most studied explanation is light intensity. The clinical summary of the International Myopia Institute (IMI) 2025 report says that, in animals, bright light increases the release of dopamine in the retina, which acts as a brake on excessive eye growth. In children, outdoor time measured as light above 1,000 lux (a unit of illuminance) is associated with a later onset of myopia.
Researchers in Singapore measured the light reaching the eyes using a child-sized mannequin head. In the shade or under a hat, light stayed above 1,000 lux; with sunglasses, it was still 11 to 43 times higher than indoor levels. The IMI adds that cloudy days count too.
The IMI acknowledges the limits: it is not yet known which intensity, type of light and duration are ideal, or whether the protection comes from light itself or from other features of the outdoor environment, such as a gaze that shifts between near and far. Artificial light therapies remain experimental, with open questions about safety.
| Setting | Light measured at eye level (lux) |
|---|---|
| Outdoors, no hat or sunglasses | 11,080 to 18,176 |
| In the shade of a tree | 5,556 to 7,876 |
| Outdoors, wearing a hat | 4,112 to 8,156 |
| Outdoors, wearing sunglasses | 1,792 to 6,800 |
| Indoors with fluorescent or LED lighting | 112 to 156 |
Measurements in Singapore with a child-sized mannequin head (Lanca and colleagues, Translational Vision Science and Technology, 2019). The threshold linked to protection is more than 1,000 lux.
How much outdoor time does a child need to prevent myopia?
The technical note Uso de telas na infância e saúde ocular (Screen use in childhood and eye health), by the SBOP with the CBO and the SBP, advises encouraging outdoor activities, with indirect sun exposure, for at least 2 hours a day. The IMI confirms that this target is still valid for delaying myopia.
The Brazilian Guidelines for the Treatment of Myopia (Diretrizes Brasileiras para o Tratamento da Miopia), published on June 29, 2023, by the SBOP and the Brazilian Society of Contact Lenses, Cornea and Refractometry (SOBLEC), cite the Taiwan study: at least 11 hours a week outdoors were effective in preventing myopia from appearing in children who were not nearsighted. The CBO Miopia report highlights studies in which 40 minutes a day already significantly reduce the risk.
On September 11, 2026, at the 70th Brazilian Congress of Ophthalmology in Salvador, the SBOP and the CBO launched the booklet Mais Tempo ao Ar Livre, Mais Saúde para os Olhos (More Time Outdoors, More Health for the Eyes), which repeats the 2-hour daily target and will be distributed to health and education departments across Brazil, according to Agência Brasil.
Two hours a day add up to 14 a week, and no club meeting covers that on its own: the rest comes from recess in the schoolyard, walking to school when the route is safe and an afternoon at the park.
How do Pathfinder Club activities help the eyes?
Long before myopia made headlines, the Pathfinder Club was already taking kids outside, and many activities make the eyes look far away: the next trail marker, a point on the horizon, the bird on a branch.
- Hikes: hours on end under natural light; the guide to hiking and trails helps you plan safely.
- Birdwatching: trains the eye to spot distant movement, and the Birds Honor gives every outing a goal.
- Orienteering: map and compass call for landmarks in the distance.
- Yard time: drill, games and pioneering, with no screen in between.
Another free adjustment is moving Class and Honor sessions that don't need a room outdoors: in the Singapore measurements, the shade of a tree had dozens of times more light than an indoor room.
Sunlight and fresh air are among the eight natural remedies valued by the Seventh-day Adventist Church, and myopia research reaches a similar conclusion by another path. The club encourages the habit and adds hours, but no activity replaces an eye exam with an ophthalmologist.
How can kids enjoy the sun without risk to skin and eyes?
Medical societies talk about indirect sun exposure: what helps the eyes is daylight brightness, which also reaches the shade. According to Brazil's National Cancer Institute (INCA), shade cuts ultraviolet radiation by up to 50%, and it is best to avoid unprotected sun between 10 a.m. and 4 p.m.
For the eyes, the AAO recommends sunglasses with 100% UV protection (or UV400) and a wide-brimmed hat, for children too, and the IMI states that hats and sunglasses do not cancel the protective effect of outdoor time. Sunscreen, repellent and reapplication are covered in the guide to sunscreen and insect repellent on outdoor activities.
How does the 20-20-20 rule work, and what about screens?
The SBOP technical note describes the 20-20-20 rule: every 20 minutes of near work, take a break of at least 20 seconds looking at something 20 feet away, about 6 meters. The pause relaxes the effort of focusing up close, which doctors call accommodation.
At the club, the rule becomes a game: during an indoor class, someone in the Unit keeps time and, every 20 minutes, everyone looks out the window for the farthest thing they can see.
The same note advises choosing the larger, more distant screen, holding the device about an adult's arm length from the face and keeping the brightness equal to or lower than the room's. Limits by age are in the article on mindful screen use.
As for phones, the SBOP points to too much near vision as a risk factor, and a phone is usually held closer to the face than a book. The IMI, however, considers the impact of electronic devices on myopia inconclusive. The firm point: too much screen time usually means too little time outdoors.
Can myopia in children be cured? Signs it is time to see an eye doctor
Myopia in children cannot be cured with home habits, and none of the medical documents consulted presents outdoor time as a way to reduce the prescription. The Brazilian Guidelines for the Treatment of Myopia treat it as a complement, not a stand-alone intervention. According to the SBOP, care includes correcting the prescription and monitoring progression at regular visits; any other treatment is the ophthalmologist's decision, after a complete exam.
According to the AAO, common signs in children are squinting, trouble seeing far away (the school board, for example), eye strain and headaches. At the club, the Counselor often notices the Pathfinder who can't find the trail marker the others have already spotted, or who has to walk right up to the bulletin board.
If you notice something, talk to the family discreetly, without singling the child out in front of the Unit. Only an exam can tell myopia apart from other conditions, such as the pseudomyopia the SBOP describes in heavy phone users. A Pathfinder who already wears glasses takes part in everything and follows the ophthalmologist's guidance.