Blue eyes photography
Eye color is a polygenic phenotypic character determined by 2 distinct factors: the pigmentation of the eye’s iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.
In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of melanin in theiris pigment epithelium (located on the back of the iris), the melanin content within the iris stroma (located at the front of the iris), and the cellular density of the stroma.
The appearance of blue, green, as well as hazel eyes results from the Rayleigh scattering of light in the stroma, a phenomenon similar to that which accounts for the blueness of the sky.
Neither blue nor green pigments are ever present in the human iris or ocular fluid. Eye color is thus an instance ofstructural color and varies depending on the lighting conditions, especially for lighter-colored eyes.
There is no blue pigmentation either in the iris or in the ocular fluid. Dissection reveals that the iris pigment epithelium is brownish black due to the presence of melanin. Unlike brown eyes, blue eyes have low concentrations of melanin in the stroma of the iris, which lies in front of the dark epithelium. Longer wavelengths of light tend to be absorbed by the dark underlying epithelium, while shorter wavelengths are reflected and undergo Rayleigh scattering in the turbid medium of the stroma.
This is the same frequency-dependence of scattering that accounts for the blue appearance of the sky. The result is a “Tyndall blue” structural color that varies with external lighting conditions.
Source : Wikipedia
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By Aldo Danyel
By Noukka Signe
By David Talley
By Toni Blay