[edit] Hazel

This eye shows a mixture of brown, green and amber colors.

Some eye colors are too mixed to identify properly, and are identified as hazel for simplicity's sake.

Hazel eyes are due to a combination of a Rayleigh scattering and a moderate amount of melanin in the iris' anterior border layer.^[20][5] Hazel eyes often appear to shift in color from a light brown to a medium golden-green. A number of studies using three-point scales have assigned "hazel" to be the medium-color between the lightest shade of blue and darkest shade of brown.^{[50][51][52][53][54][55][56]} This can sometimes produce a multicolored iris, i.e., an eye that is light brown near the pupil and charcoal or amber/dark green on the outer part of the iris (and vice versa) when observed in sunlight. Hazel is commonly found in some regions of the Middle East, Europe, North America, parts of Central Asia, parts of North India, Northern Pakistan and in Afghanistan. Rarely, hazel eyes can be found in people of sub-saharan African, Native American and East Asian descent.

Definitions of the eye color "hazel" vary: it is sometimes considered to be synonymous with light-brown, gold, or other times with green or dark green.^{[57][45][50][52][55][58][59] [60][61]} In North America, "hazel" is often used to describe eyes that appear to change color, ranging from light brown to green and even gray, depending on current lighting in the environment.
 

 Red

The eyes of a person with albinism may appear red under certain lighting conditions due the very low quantities of melanin. "True" red eyes also exist in albinistic populations, but are very rare. ^[62]

The red-eye effect in flash photographs makes the pupils (rather than the irises) appear red. It is not related to eye color.