The Reason Why Hazel Eyes Seem To Change Color

Now here's the crazy part: We just covered that hazel eyes have multiple different colors in them in a starburst pattern, yes? But what if we told you the only actual color in hazel eyes (or in eyes of any color, for that matter) is brown. What? We know, we know. Let us explain: melanin, the same thing responsible for the color of your skin, is responsible for the color of your eyes. And just like your skin, the more melanin there is, the darker your eyes will appear (Owlcation). So if there is only melanin (brown) in hazel eyes, how can they appear to be multiple different colors? As noted by Science Alert, this is thanks to the Tyndall effect, which is similar to Rayleigh scattering, the phenomenon makes both the ocean and the sky appear blue (via Fuel Cells and Hydrogen).

Basically, the way that light is scattered combined with the level of melanin in different parts of the eye determines the way hazel eyes appear. Where there is brown, there is an abundance of melanin, while gold, green, or amber have less melanin. And blue? Blue actually has no melanin or pigment at all, but the way the light plays upon the eye and scatters makes that portion of the iris appear blue, the way the ocean and sky appear blue without actually containing pigment themselves.