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Rather, blue eyes result from structural color in combination with certain concentrations of non-blue pigments. The iris pigment epithelium is brownish black due to the presence of melanin. [54] Unlike brown eyes, blue eyes have low concentrations of melanin in the stroma of the iris, which lies in front of the dark epithelium.
Eye color, specifically the color of the irises, is determined primarily by the concentration and distribution of melanin. Although the processes determining eye color are not fully understood, it is known that inherited eye color is determined by multiple genes. Environmental or acquired factors can alter these inherited traits. [7]
Blue eyes actually contain no blue pigment. The colour is caused by an effect called Tyndall scattering. Blue eyes do not actually contain any blue pigment. Eye colour is determined by two factors: the pigmentation of the eye's iris [48] [49] and the scattering of light by the turbid medium in the stroma of the iris. [50]
If you've ever heard "your eyes change color a lot," its because of light! Melanin absorbs light so the less melanin, like people with blue eyes, more light is reflected back out of the eye.
Human eye pigmentation in Europe Among human phenotypes, blue-green-gray eyes are a relatively rare [citation needed] eye color and the exact color is often perceived to vary according to its surroundings. The iris is usually strongly pigmented, with the color typically ranging between brown, hazel, green, gray, and blue.
[10] [11] The blue iris is an example of a structural color because it relies only on the interference of light through the turbid medium to generate the color. Blue eyes and brown eyes, therefore, are anatomically different from each other in a genetically non-variable way because of the difference between turbid media and melanin.
Amelanistic mammals have white hair, pink skin, and eyes that have a pink, red, or violet appearance. Reddish eyes are due to the lack of pigment in the iris pigment epithelium. When the stroma is unpigmented but the iris pigment epithelium is not, mammalian eyes appear blue. Melanin in the pigment epithelium is critical for visual acuity and ...
Ocular melanosis (OM) is a blue-gray and/or brown lesion of the conjunctiva that can be separated into benign conjunctival epithelial melanosis (BCEM) and primary acquired melanosis (PAM), of which the latter is considered a risk factor for uveal melanoma. [1]