Global Eye Color Distribution: Statistics and Geographic Patterns

Worldwide Eye Color Prevalence

• Brown: ~79% (dominant globally).
• Blue: ~8–10%.
• Hazel: ~5%.
• Green: ~2%.
• Amber / Gray: ~1% each.

Genetic Basis

Primarily determined by OCA2 and HERC2 genes on chromosome 15 regulating melanin production in iris stroma. Brown is dominant; blue recessive. Green/hazel involve intermediate melanin + structural light scattering (Rayleigh).

Geographic & Ethnic Variation

• High brown (>90%): East Asia, Southeast Asia, Africa, Indigenous Americas, Middle East.
• High blue (>50%): Northern/Eastern Europe (Baltic, Scandinavia).
• Green/hazel peaks: Celtic regions (Ireland, Scotland), Central Europe, parts of West Asia.

Clinical Note

Eye color can change in infancy (melanin deposition completes by 12–18 mo). Pathologic changes (heterochromia, Fuchs heterochromic iridocyclitis, Horner syndrome, melanoma) require evaluation.