Hazel eyes are difficult to define because their appearance changes with surrounding colors and lighting. Like blue and green eyes, hazel eyes are as reflective as a pond. If the sky is blue, the water appears to be blue; if the sky is overcast, the water appears to be gray or brown. Captured in photographs, without the benefit of the natural scattering of light, hazel eyes often appear brown or dark gray.
Scientists once thought that eye color could be explained with a neat little dominant single gene theory, one that most of us were taught in school. Brown eyes are dominant over blue and eye color is determined by the dominant family gene pattern. Current theory accepts a more complicated scenario, that the amazing variation inherent in human eye color is determined by two major genes and many minor ones.
Eye color is determined by melanin, the same pigment that determines skin and hair color. The more melanin that is present, the darker the color, with the spectrum ranging from glacial ice blue to inky black. Little pigment produces light blue eyes, lots of pigment makes for dark brown or, in rare cases, black eyes.
Most hazel eyes have concentric rings, with brown around the pupil, then a ring of green and sometimes gold or gray. The outer color is rarely solid. It is most often flecked with gold, darker green, brown, or blue. The effect, even when looking directly at the eye close-up, is a kaleidoscope pattern with only an overall impression of one color or another under different lighting conditions.
People with hazel eyes can control the surrounding colors to help reflect the color they want to project. Eye shadow and clothing can be coordinated to make eyes appear to be gold, green, gray, or brown. Hazel-eyed women who want to intensify a specific eye color should use three shades of eye shadow color—a lighter shade from lashes to eyebrows, a medium shade only in the crease of the eyelid, and a darker shade smudged just above the eyelashes. Blend the shades at the lines for a smooth color transition and finish with black mascara and eyeliner. Wear clothing in a light shade of the same color, and eye color will complement the outfit perfectly. For a less dramatic effect, try purple shadows to enhance the green and cool grays and blues to make the brown pop.
Hazel eyes are commonly found in people of European descent, parts of the Middle East, and in regions of Central and South Asia. Brown is the most common eye color in the United States, followed by blue, hazel, green, and then rare colors like black, or the pink coloration associated with albinism.
It is a myth that eye color changes with mood, however in the right lighting, the salt content of tears will enhance lighter colors, making the color appear brighter. Raising or lowering of eyelids can change the light refraction, so an expression of anger or passion may make eye color darken or lighten simply because the eyes narrow or widen to block or admit more light.