The human eye displays a remarkable range of colors, a fascinating trait emerging from intricate biological processes. From deep browns to striking blues and greens, the spectrum of eye hues highlights the unique genetic tapestry of humanity.
The Global Prevalence of Hazel Eyes
Hazel eyes are a distinct and relatively less common eye color globally. Approximately 5% of the world’s population has hazel eyes. They are more frequently observed in populations from parts of Europe, North Africa, and the Middle East.
Understanding Hazel Eye Color
Hazel eyes are characterized by their unique blend of colors, typically featuring a mix of brown, green, and gold. Sometimes, flecks of blue or amber can also be present within the iris. This multi-toned appearance distinguishes hazel eyes from solid brown or green eyes. Hazel eyes can appear to change color under different lighting conditions, shifting between their constituent hues. The distribution of color in hazel eyes often creates a “sunburst” effect, with different shades near the pupil and at the outer rim of the iris.
The Science Behind Eye Color Variation
Eye color is determined by the amount and distribution of melanin within the iris. The iris contains two types of melanin: eumelanin, which produces brown, and pheomelanin, which contributes to amber, green, or hazel tones. Beyond pigmentation, the scattering of light within the iris’s stroma also plays a significant role in perceived eye color. This phenomenon, similar to Rayleigh scattering that makes the sky appear blue, influences how light wavelengths are reflected. Hazel eyes have an intermediate amount of melanin, which allows for a combination of light absorption and scattering, resulting in their characteristic blend of colors.
How Hazel Compares to Other Eye Colors
Brown eyes are the most widespread, accounting for 70% to 79% of the global population. Blue eyes are the second most common, found in approximately 8% to 10% of people worldwide. Green eyes are rarer, present in about 2% of the world’s population. Gray eyes are even less common, making up about 3% of individuals globally. This comparison highlights that while hazel eyes are not as ubiquitous as brown or blue, they are more prevalent than green or gray eyes.