The World Through Blurred Eyes

The Global Rise of Childhood Myopia and Its Long-Term Consequences

A nine-year-old child leans over an open exercise notebook, her pencil moving across ruled paper without hesitation. Every detail six inches from her face is sharp. But when she raises her eyes to copy a problem from the blackboard across the classroom, the chalk lines dissolve into an indistinct white smear. She squints, leans forward, and waits for the blur to resolve. It does not.

For a parent, the first sign may seem straightforward: a child’s distance vision is blurred, and glasses restore clarity. But myopia can involve more than a prescription that needs updating. In myopia, the eye’s optical power is too strong for its length, or the eye is too long for its optical power, so distant objects focus in front of the retina. In some children the eye keeps elongating through adolescence, which raises the risk of complications later in life.

Across many urban populations, childhood myopia has become increasingly common, and researchers now study it as a public-health problem as well as an optical one.

The Scale of the Shift: Models, Realities, and Trajectories

Two terms matter before any number does. Prevalence is the proportion of a group affected at a given time. Incidence is the rate at which new cases appear. A projection is a model-based estimate of the future, not an observation.

Much of the modern alarm about nearsightedness traces back to a 2016 global model by Brien Holden and colleagues, published in Ophthalmology. It projected that by 2050 roughly 49.8% of the world’s population, about 4.76 billion people, could be myopic, with 9.8% having high myopia.

That forecast covers every age band, not children alone. A narrower picture comes from a 2025 systematic review and meta-analysis by Liang and colleagues in the British Journal of Ophthalmology, which pooled 276 studies of 5.41 million children and adolescents in 50 countries. It estimated that pooled myopia prevalence among children and adolescents rose from 24.32% in 1990 to 35.81% in 2023, and it projects 39.80% for children and adolescents by 2050. The authors estimate that the number of children and adolescents with myopia could exceed 740 million by then. This is a model-based estimate, not a count of observed cases or annual new diagnoses.

One analysis is an all-age projection; the other tracks school-age cohorts. Together, they indicate a substantial global burden, while measuring different populations and relying on different projections.

Prevalence alone does not explain why clinicians are concerned. What matters is what progressive eye growth can mean over a lifetime.

The Anatomy of Elongation: Why the Prescription Matters

In a normally developing eye, a state known as emmetropia, the optical power of the cornea and lens matches the length of the eyeball, and light from distant objects converges on the central retina.

In myopia, the eye’s optical power and length are mismatched, so distant light focuses in front of the retina and the image is blurred. Concave lenses move the focal point back and restore clear vision, but they leave the length of the eye unchanged. As the eye lengthens, the thin tissues at the back of the globe are stretched.

That stretching helps explain why myopia matters beyond blurred vision. Greater axial elongation is associated with higher risks of certain retinal and other ocular complications, particularly in high myopia. Four terms describe the spectrum:

Myopia is a refractive error: blurred distance vision, usually correctable with spectacles or contact lenses.
Progressive myopia is continued axial elongation during childhood, with prescriptions growing more negative over the years.
High myopia is defined primarily by refractive error, commonly −6.00 dioptres or more myopic. An axial length above roughly 26 millimetres is a related anatomical indicator, but the two measures are not interchangeable.
Pathological myopia refers to structural damage associated with excessive elongation, such as chorioretinal atrophy, posterior staphyloma or macular degeneration. It is defined by those changes, not by the size of the prescription alone.

A 2020 review and meta-analysis by Haarman and colleagues, covering studies published before June 2019, examined how the degree of myopia relates to myopic macular degeneration, retinal detachment, cataract, open-angle glaucoma and blindness. Risk was highest in high myopia, while low and moderate myopia also carried considerable risk. These risks vary with the degree of myopia and the complication considered; higher risk does not mean that an individual child will develop a particular condition.

Earlier onset leaves more years in which myopia may progress before the eye stabilises. Greater myopia is associated with higher risks of later complications, although individual trajectories vary.

Beyond the Screen: Untangling the Environmental Web

Popular accounts often blame smartphones and tablets alone. The research points to a wider set of influences.

Inherited susceptibility matters: children with myopic parents are more likely to become myopic themselves. Gene pools do not change across whole populations in three decades, however, so the rapid rise in prevalence points to changes in children’s environments. Genes and environment interact, and neither predicts an individual child’s outcome with certainty.

Screens are one candidate among several. A 2026 systematic review and meta-analysis of 33 observational studies, by Song and colleagues in Biomedical Reports, pooled comparisons of near-work exposure and childhood myopia. The pooled estimate corresponds to 8.4% higher odds of myopia in the exposure comparisons analysed (odds ratio 1.084, 95% confidence interval 1.060 to 1.108). The studies used different measures of near work and showed substantial heterogeneity, so this estimate should not be interpreted as a universal effect of a specific amount of screen time. Because the studies were observational, the association does not establish causation. Near work includes printed books, handwritten homework and classroom study as well as phones and tablets, and it overlaps with study demands and time indoors.

Time outdoors is among the best-supported protective factors. Randomised school trials, including those led by He in Guangzhou and Wu in Taiwan, found that added outdoor time reduced the number of children who became myopic, and a review of the interventions recommended in China’s national plan, discussed below, reached the same conclusion for school-aged children.

Why outdoor time protects is less settled. One hypothesis involves light intensity: outdoor light is often many times brighter than indoor classroom lighting, and animal experiments suggest that bright light stimulates retinal dopamine, a signalling molecule that may help restrain scleral remodelling and eye growth. How far this pathway explains the effect in humans remains under investigation.

Optics may also play a part. In experimental models, the pattern of defocus across the retina can influence eye growth, and some myopia-control lenses are designed around that principle. The pathways are complex and not fully resolved, and no single optical signal explains every case of elongation.

Separating these overlapping exposures, and the mechanisms behind them, remains the central unresolved problem, and it shapes how evidence from different countries should be read.

Epicentres and Divergences: A Comparative Geography

The international picture is uneven. Some evidence captures unusually high prevalence in selected populations; other evidence concerns prevention programmes, policy or access to correction. These findings illuminate different parts of the problem and should not be treated as directly comparable rates.

South Korea. In a 2010 cohort of 23,616 male conscripts aged 19 in Seoul, studied by Jung and colleagues, 96.5% had myopia. East Asia is the historical epicentre of high myopia, but this figure describes one group of young men. It cannot stand in for all Korean children, for women, or for the present-day population.

Singapore. The National Myopia Prevention Programme, launched in August 2001 by the Health Promotion Board with the Ministry of Education and the Ministry of Health, combines vision screening with health education on eye care. Its existence marks a sustained national commitment to prevention; it does not by itself show how well prevention has worked.

Taiwan. An interrupted time-series analysis by Wu and colleagues examined Tien-Tien 120, a programme encouraging 120 minutes of outdoor time during the school day. It found that the programme was followed by a reversal in the previous trend of rising reduced uncorrected visual acuity. The study did not directly measure new cases of myopia, and evidence that outdoor time prevents onset comes mainly from separate trials.

China. In August 2018, eight national departments jointly issued the Comprehensive Prevention and Control of Myopia in Children and Adolescents Implementation Plan, which Jan and colleagues describe in the Bulletin of the World Health Organization. It addresses outdoor activity, the management of homework and school eye-health measures, among others. Some provisions encourage families and schools to act, others set expectations for institutions, and how far each is enforced varies. A systematic review by Zhu and colleagues of the interventions the plan recommends concluded that the evidence supported increasing outdoor time and reducing near-work time to lower the incidence of myopia in school-aged children, while the interventions reviewed had limited effects on slowing progression once myopia was established.

India. A 2025 systematic review and meta-analysis by Kumar and colleagues, drawing on 43 cross-sectional studies of Indian schoolchildren published after 2018, estimated a pooled prevalence of about 11% for refractive errors overall and about 8% for myopia. Estimates were higher in studies using cycloplegic examination (12%) than in those without it (10%). City-specific studies may report higher figures, but they reflect particular ages, school types, locations and diagnostic methods, and the pooled estimates should not be read as the prevalence in every region. They describe prevalence, not access to diagnosis or treatment. The public-health burden also depends on whether children with uncorrected refractive errors are identified and can obtain appropriate spectacles and follow-up.

Europe and North America. Myopia is also common among young people in Western countries, but credible comparison requires studies matched on age range, year and definition. Without them, a single cross-country rate would imply more precision than the evidence supports.

The comparisons point to distinct public-health tasks. South Korea’s conscript data illustrate the potential scale of myopia in a particular high-prevalence cohort; Taiwan’s findings concern a programme-associated change in uncorrected visual acuity; India’s pooled estimates describe prevalence across studies with different diagnostic methods. China’s policy and Singapore’s prevention programme show how governments have responded, but their existence alone does not establish effectiveness. Comparing policies requires consistent outcome measures, comparable populations and evidence that separates programme activity from its effects.

The Race to Slow Progression: Clinical Interventions

For decades, the standard response to childhood myopia was to prescribe single-vision glasses and strengthen them at each visit as the prescription worsened. Clinicians now try to slow elongation while the eye is still growing, guided by resources such as the International Myopia Institute’s clinical management guidelines.

Preventing onset

For children who are not yet myopic, time outdoors is the main tool. The World Health Organization advises at least 90 minutes outdoors during daylight hours, which may help delay the onset of myopia and slow its progression. That figure is guidance, not a guaranteed threshold: more time may bring further benefit, and less is not without value. The evidence is strongest for preventing onset, and the ability of outdoor time to slow progression once myopia is established appears more limited.

Slowing progression

For children who are already myopic, the goal changes: treatment aims to slow further progression and axial elongation, not reverse elongation that has already occurred. The options differ in what they require of the child and in how they are thought to work.

Defocus spectacle lenses slow elongation while giving clear vision. A two-year randomised trial in Hong Kong by Lam and colleagues found that Defocus Incorporated Multiple Segments (DIMS) lenses slowed myopia progression and axial elongation compared with single-vision lenses. A two-year randomised trial of Highly Aspherical Lenslet Target (H.A.L.T.) lenses, by Bao and colleagues, reported a similar direction of effect. Both designs surround a clear central zone with microlenses that project myopic defocus in front of the peripheral retina.
Low-dose atropine drops, used nightly, slow elongation with relatively little effect on near vision at the lowest concentrations. They act on muscarinic receptors and are thought to inhibit scleral remodelling. In the LAMP study of Hong Kong children aged 4 to 12, led by Yam, 0.05% atropine was the most effective of the concentrations tested, with manageable side effects. Concentrations, formulations and protocols vary between countries and clinics.
Orthokeratology gives clear daytime vision without glasses. Custom rigid lenses worn overnight temporarily reshape the cornea, and the randomised ROMIO trial by Cho and Cheung found slower axial elongation than with single-vision spectacles. The lenses require strict hygiene and professional monitoring because of the risk of microbial keratitis.

These trials differ in population, outcome measure and follow-up, so their effect sizes are not interchangeable.

A two-year randomised trial published in October 2026 in the Journal of Optometry by Wnękowicz-Augustyn and colleagues compared DIMS lenses plus placebo drops with single-vision spectacles plus nightly 0.01% atropine in 110 Polish and Ukrainian children aged 6 to 16. It reported less axial elongation over 24 months in the DIMS group, in line with the direction of the trial’s one-year interim report. That is an observed result from one trial, and adherence matters whenever daily drops are compared with spectacles. The trial adds comparative evidence for these two regimens in this population, but treatment choice still depends on clinical circumstances and evidence beyond a single study.

Monitoring and management

Regular eye examinations, timely prescription updates and attention to signs of progression or complications remain part of care for every child with myopia. Which option suits a given child depends on age, rate of progression, clinical assessment, suitability and local availability, and that decision belongs with an eye-care professional.

Public Policy and the Redesign of Childhood

Clinical care is only one part of the response. Prevention, early identification and access to correction also depend on what schools, families and health systems can provide. Myopia-control treatments carry costs, and whether health systems or families bear them varies by country. The WHO’s 2019 World report on vision also describes eye-care services and trained personnel as unevenly distributed between and within countries.

The evidence is strongest for outdoor time, screening and access to correction. Responsibility for them falls to different actors:

Schools: protect regular outdoor time in the daylight hours of the school day, and support early identification of children with vision problems.
Families: encourage outdoor activity and balanced daily routines, with breaks from sustained close work.
Health systems: expand access to eye examinations, affordable spectacles and follow-up, consistent with the WHO’s SPECS 2030 goal of improving effective coverage of refractive-error services.
Governments and researchers: evaluate interventions and measure outcomes consistently, so that policy rests on evidence about myopia itself and not only on proxies.

Some further ideas are proposals rather than established measures. School buildings with more daylight, broader windows and views of distant horizons may make outdoor and daylight exposure easier, but architectural features have not been shown, on their own, to prevent myopia, and they need evaluation. The 20-20-20 habit, looking at something 20 feet away for 20 seconds every 20 minutes, is a sensible way to ease eye strain during prolonged close work. It has not been shown to prevent or slow axial elongation.

A Clearer Horizon

Return to the child at the blackboard. Her blur is a matter of glasses today, and it is also a question about how far her eyes will grow in the years ahead. The answer depends on inherited susceptibility, on the places where she spends her days, and on the care she can reach.

The scale of the global rise will depend not only on how many children become myopic, but on how effectively societies prevent onset, slow progression and ensure access to timely correction and care.

Sources

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