What is the worldwide prevalence of myopia overall and the proportion of low‑grade (‑0.50 D to ‑3.00 D), moderate‑grade (‑3.00 D to ‑5.00 D), and high‑grade (≤‑5.00 D) myopia?

Global Prevalence of Myopia by Severity Grade

The worldwide prevalence of myopia is approximately 26.5% in adults and 11.7% in children, with high myopia (≤-5.00 D) affecting 7.4% of myopic populations, though specific proportions for low-grade and moderate-grade myopia are not consistently reported across global epidemiological studies. 1

Overall Global Prevalence

The global burden of myopia varies substantially by age and geography:

• Adults (age 40+): Overall myopia prevalence ranges from 25-36% in U.S. populations, with Chinese Americans showing 35.1% prevalence (≥-0.50 D) 1
• Children and adolescents: Global prevalence is 11.7%, though this masks dramatic regional variation from 4.9% in South-East Asia to 18.2% in the Western Pacific region 1
• Projected trends: Meta-analyses predict myopia prevalence will reach 49.8% globally by 2050, affecting nearly half the world's population 2

High Myopia Prevalence (≤-5.00 D)

High myopia represents the most clinically significant category due to associated vision-threatening complications:

• Among Chinese Americans aged 50+, high myopia (≤-5.00 D) affects 7.4% of the population 1
• Global projections estimate high myopia will increase from 2.7% (2000) to 9.8% by 2050 2
• In Chinese populations specifically, high myopia prevalence in school-aged children ranges from 8.89% in middle school to 20.12% in high school students 3

Low and Moderate Myopia Distribution

The evidence base provides limited specific breakdowns by the requested severity categories, but available data suggests:

• In Weifang, China, among students: low myopia (-0.75 to -3.00 D) affects 48.56% of elementary students, 47.30% of middle school students, and 31.62% of high school students 3
• Moderate myopia (-3.01 to -5.99 D) data is rarely reported separately in epidemiological studies, representing a gap in the literature 3
• The majority of myopic individuals fall into the low-to-moderate range, as high myopia consistently represents less than 10% of total myopia cases globally 1, 2

Critical Geographic and Demographic Variations

East Asian populations demonstrate dramatically higher prevalence across all severity grades:

• Taiwan: 84% of 16-18 year-olds have myopia, with 77% of 12-year-olds affected 1
• Singapore: 79% of 18-year-old males and 85% of medical students (ages 19-23) have myopia 1
• Korea: 71% prevalence in ages 19-49 1
• Japan: 41.8-50% in adults aged 40+, with increasing trends from 38% (2005) to 46% (2017) 1

In contrast, Western populations show lower rates:

• United States: 25-36% in adults aged 20-40+, with ethnic variations (higher in non-Hispanic whites and Asian/Pacific Islanders) 1
• Australia: 16-29% in adults aged 49-70 years 1
• Europe: Netherlands shows 2.4% in 6-year-olds; Ireland 3.3% in 6-7 year-olds, rising to 20% by ages 12-13 1

Important Methodological Considerations

A critical caveat affects all prevalence estimates:

• Cycloplegic vs. non-cycloplegic refraction produces substantially different results—one study in Inner Mongolia found 77% myopia prevalence without cycloplegia versus 54% with cycloplegia 1
• Myopia definitions vary between studies (≥-0.50 D vs. ≥-0.75 D), making direct comparisons challenging 1, 3
• The lack of standardized severity grading across studies limits precise global estimates for moderate myopia specifically 3

Age-Related Patterns

Myopia prevalence demonstrates consistent age-related progression:

• Childhood onset: 3% in ages 5-7, increasing to 8% in ages 8-10, and 14% in ages 11-12 in U.S. populations 1
• Fastest progression occurs between ages 7-9 years 3
• Adult prevalence peaks in 20s-40s (35-40%), then decreases in older adults (15-20% in 60s-80s) due to cohort effects and nuclear sclerosis-related myopic shifts 1