The color red is due to the color of the blood that circulates through them, as there is no pigment (melanin) in the iris to hide that color. In albino people and animals, the iris of the eye is translucent and therefore shows the red tone of the blood capillaries that are inside. The iris of people who are not albinos has melanin, which is the pigment that gives the different shades of eye color, but albino people are born with genetic deficiencies that prevent them from synthesizing melanin that is why they have colored eyes red.