On behalf of the European Myopia Network Council

Myopia is more than a refractive inconvenience. It is a progressive and sight-threatening condition whose global prevalence has risen from approximately 23% in 2000 to an estimated 34% in 2020, with projections approaching 50% of the world’s population by 2050 (1). High myopia, defined as a spherical equivalent of −6.00 D or worse, carries a substantially elevated lifetime risk of myopic maculopathy, retinal detachment, glaucoma, and cataract, and its prevalence may rise in parallel with the broader myopia epidemic (2). Understanding the risk factors that drive onset and progression is therefore a clinical and public health priority. Its etiology is multifactorial. The current epidemic reflects a gene–environment dynamic in which a relatively stable genetic substrate is being unmasked by profound lifestyle changes.

The genetic substrate

Family history remains one of the strongest predictors of myopia onset. Children with one myopic parent face approximately double the risk of developing myopia compared with children of non-myopic parents, while having two myopic parents multiplies the risk approximately fivefold (3). Yet genetics alone cannot explain the pace of the current epidemic. Populations with identical ethnic backgrounds show dramatically different prevalence rates depending on the environment they inhabit (4), and the generational rise in myopia unfolds far too rapidly to be driven by genetic shifts alone - genetics set the stage and the environment determines what happens on it.

An important nuance is the interaction between genotype and environment. Educational attainment has been shown to amplify genetic risk, with certain genotypes appearing particularly susceptible to myopigenic environments, an observation with direct clinical relevance for individuals who have a strong family history with intensive academic exposure (3).

Education and near work: the environmental engine

The association between educational intensity and myopia is consistently reported across decades of research (5, 6, 7). Higher educational level is linked to greater myopia prevalence across both European and Asian populations, while regions with historically lower educational attainment show prevalence rates below 10% (5). Changes in educational policy, extending mandatory schooling or raising academic performance benchmarks, have repeatedly been followed by upward shifts in myopia prevalence. In Europe, children in many countries begin formal schooling at five to six years of age, initiating sustained near-vision demands at precisely the period when ocular growth is most rapid and susceptible to environmental influence. Academic pressure tends to increase progressively through primary and secondary school, compounding cumulative near-work exposure across the most critical years of refractive development.

Continuous reading for more than 30 minutes and working at distances closer than 30 cm have been independently associated with increased odds of myopia onset, with odds ratios of 1.5 and 2.5 respectively in large population-based studies (5). A meta-analysis of cohort data found that each additional diopter-hour of near work per week increases the odds of myopia by approximately 2% (5). These associations are strongest in younger children, where earlier onset allows more time for axial elongation to progress.

Digital screen time has also been investigated, with an odds ratio of approximately 1.06 for daily use exceeding three hours (6). The evidence remains heterogeneous, and screen time may likely act partly through its dual effect of increasing near work and decreasing outdoor activity, rather than as a fully independent risk factor. Further research is required to clarify its independent contribution.

Time outdoors: the most actionable protective factor

Multiple randomized controlled trials and large cohort studies have confirmed that increasing daily outdoor time reduces myopia incidence, even when near work remains unchanged. The Guangzhou Outdoor Activity Longitudinal Trial demonstrated a reduction in three-year myopia incidence from 39.5% to 30.4% with just 40 minutes of added outdoor time per school day (8). A meta-analysis quantified that an additional hour of outdoor activity per day was associated with a 45% reduction in incident myopia, with current evidence supporting a target of at least two hours daily (5).

Bright outdoor light, typically exceeding 10,000 lux compared with indoor levels of 100–500 lux, stimulates retinal dopamine release, which may inhibit axial elongation, although evidence in children is still required to validate this theory. Crucially, the protective effect of outdoor time appears strongest for myopia onset rather than progression, reinforcing the case for primary prevention during the pre-myopic and early-school years. In Europe, achieving the recommended two hours of daily outdoor time faces context-specific barriers. In northern countries, daylight hours are substantially reduced during the winter months and climatic conditions can limit outdoor activity for extended periods. These regional constraints make school-based outdoor programs during recess particularly important as a structured and reliable means of delivering protective light exposure regardless of season.

Urbanization, lifestyle, and emerging factors

Urban residence has been associated with higher myopia prevalence, even among populations of similar genetic ancestry. In a 2026 cross-sectional study of over 77,000 children in Shandong Province, China, urban children had significantly higher myopia rates than rural peers after controlling for behavioral factors, with an odds ratio of 1.05 (6). In the European context, this urban effect is reinforced by reduced access to outdoor spaces in densely populated cities, cold winters that curtail outdoor activity in northern regions, and academic schedules that leave little time for unstructured outdoor play, all factors that compound myopia risk beyond urbanization alone.

Among additional lifestyle contributors, sleep duration and postural habits have been explored. Some studies suggest that children sleeping fewer than eight hours per night may have a higher prevalence of myopia, with proposed mechanisms including circadian rhythm disruption affecting ocular growth regulation (6). Similarly, behaviors such as reading while lying down or using digital devices during transit have been associated with increased myopia risk in large-scale datasets (OR 1.09–1.22) (6). However, the current evidence remains limited and heterogeneous and is not yet strong enough to establish these factors as independent or causal contributors. Sex differences are modest and not always consistent, with more recent studies showing that girls tend to develop myopia earlier than boys, with a pooled relative risk of 1.28 across 19 cohort studies (9).

Biometric markers and clinical risk stratification

Several ocular biometric parameters are associated with myopia onset and can inform early clinical risk stratification. Reduced hyperopic reserve, assessed through cycloplegic spherical equivalent, has emerged as a predictor of myopia onset, and its measurement is increasingly recommended as a standard component of pediatric eye screening (10). Longer axial length and a higher axial length-to-corneal radius ratio at baseline have been associated with a relative risk of 1.38 for subsequent myopia onset (9). Deeper anterior chamber depth and thinner crystalline lens have also been identified as early biometric markers, though the certainty of evidence for these parameters remains low (9).

Clinical implications

Understanding the individual risk factor profile of a child (family history, age of onset, time outdoors, near-work habits, and early refractive status) allows clinicians to stratify risk and time interventions more precisely. Children with two myopic parents, limited outdoor activity, reduced hyperopic reserve, and early onset represent the highest-priority group for proactive management. At the population level, school-based interventions mandating outdoor time during recess have shown measurable impact on prevalence trends in several East Asian countries, offering a scalable model that merits evaluation in the European context.

The message for parents, educators, and clinicians is consistent across the evidence base, protecting children’s vision requires encouraging outdoor time every day, moderating sustained near work with regular breaks, maintaining safe viewing distances, and monitoring those with the greatest genetic susceptibility from the earliest school years.

Table 1. Summary of main risk factors for myopia onset and progression 

About the European Myopia Network

The European Myopia Network (EMN) — myopianetwork.eu — is an open educational and scientific initiative bringing together experts from European countries. EMN conducts innovative research, organizes the free-access Myopia 2026 online meeting on June 5 (miopia.pl/conference-2026), and provides educational content. Registration, participation, and all materials are freely accessible.