Japan has among the world's highest documented myopia rates. A clinical and epidemiological reference covering the 2025 nationwide claims database study, Tokyo prevalence data, and treatment context.
Japan presents one of the most documented myopia epidemics in the world. A landmark 2025 nationwide study using Japan's National Database of Health Insurance Claims (the largest national health insurance claims database in the world, covering 14.9 million children aged ≤14 years) found a prevalence of 36.8% as of October 2020. The number of new myopia cases was highest at age 8, and annual incidence increased from 853.3 cases per person-year in 2015 to 910.7 in 2020 — confirming an accelerating trend.
At a school-based level, data from Tokyo paints a more alarming picture. A cross-sectional study by Hashimoto et al. (JAMA Ophthalmol 2019) of 1,416 schoolchildren found myopia prevalence of 76.5% among elementary students and 94.9% among junior high students — using noncycloplegic autorefraction, which may underestimate true myopia compared to cycloplegic measurement. High myopia (≥−6.00D) was already present in 4.0% of elementary and 11.3% of junior high students.
The Tokyo Myopia Study (J Clin Med 2022) assessed children aged 3–12 years and found myopia prevalence of 60.2% among preschoolers and 82.2% among elementary school children, with mean axial length growing from 22.12mm at age 3 to 24.57mm at age 12. These figures place Japan alongside China and South Korea as a country with epidemic-level childhood myopia.
The 2025 nationwide claims study found that annual incident cases of myopia increased in both the 5–9-year-old and 10–14-year-old age groups from 2014 to 2020. This reflects earlier onset rather than simply more prevalent older cohorts — consistent with global patterns of accelerating paediatric myopia. The prevalence of high myopia also increased with age, peaking at 0.46% among children aged 10–14 years.
| Age group / setting | Prevalence | Source |
|---|---|---|
| Preschool (3–6 yr), Tokyo | 60.2% | Tokyo Myopia Study, J Clin Med 2022 |
| Elementary (6–11 yr), Tokyo | 76.5% | Hashimoto et al. JAMA Ophthalmol 2019 |
| Junior high (12–14 yr), Tokyo | 94.9% | Hashimoto et al. JAMA Ophthalmol 2019 |
| National ≤14 yr (claims data, 2020) | 36.8% | Nationwide claims study, Ophthalmol Sci 2025 |
| High school (2022 national survey) | 71.56% | Ministry of Education data cited in PMC11964782 |
The discrepancy between the national claims database figure (36.8%) and the Tokyo school-based data (76.5–94.9%) reflects several factors: the claims database captures only children who received a medical claim for myopia — likely undercounting mild cases; the Tokyo studies used non-cycloplegic autorefraction in urban, high-burden schools; and the national claims data includes younger children (under 6) who have much lower rates. National Japanese Ministry of Education visual acuity data for 2022 showed that 37.88% of elementary, 61.23% of middle school, and 71.56% of high school students had visual acuity below 1.0 (a proxy for significant myopia) — the highest percentages ever recorded for each level.
Japanese data confirmed the global pattern of accelerated myopia during COVID-19 school closures. Increased indoor time, screen exposure, and reduced outdoor activity in 2020–2021 were associated with measurable increases in myopia progression and incidence in paediatric cohorts. This is consistent with the IMI 2025 Digest's citation of multiple studies documenting sharp increases in myopia during lockdown periods.