The most common eye color worldwide is brown. Approximately 70-80% of the global population has brown eyes, making it the dominant eye color across most regions, especially in Africa, Asia, and parts of the Americas

. Brown eyes result from a relatively high concentration of melanin in the iris, which also provides protection against sun damage

. In the United States, brown eyes are also the most prevalent, found in about 45% of the population, followed by blue (27%), hazel (18%), and green (9%)

. In summary, brown is the most common eye color globally and in most populations due to genetic and evolutionary factors related to melanin production and environmental adaptation