In humans, the inheritance pattern followed by blue eyes is considered similar to that of a recessive trait (in general, eye color inheritance is considered a polygenic trait, meaning that it is controlled by the interactions of several genes, not just one). ![]() The result is a " Tyndall blue" structural color that varies with external lighting conditions. This is the same frequency-dependence of scattering that accounts for the blue appearance of the sky. 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. Unlike brown eyes, blue eyes have low concentrations of melanin in the stroma of the iris, which lies in front of the dark epithelium. Dissection reveals that the iris pigment epithelium is brownish black due to the presence of melanin. There is no blue pigmentation either in the iris or in the ocular fluid. Many animals such as canines, domestic cats, owls, eagles, pigeons and fish have amber eyes as a common color, whereas in humans this color occurs less frequently. In humans, yellowish specks or patches are thought to be due to the pigment lipofuscin, also known as lipochrome. The bright yellow eyes of the great horned owl are thought to be due to the presence of the pteridine pigment xanthopterin within certain chromatophores (called xanthophores) located in the iris stroma. ![]() The eyes of some pigeons contain yellow fluorescing pigments known as pteridines. Amber eyes may also contain amounts of very light gold-ish gray. Even though amber is considered to be like gold, some people have russet or copper colored amber eyes that many people mistake for hazel, though hazel tends to be duller and contains green with red/gold flecks, as mentioned above. Also, hazel eyes may appear to shift in color and consist of flecks and ripples, while amber eyes are of a solid gold hue. Amber eyes should not be confused with hazel eyes although hazel eyes may contain specks of amber or gold, they usually tend to comprise many other colors, including green, brown and orange. This may be due to the deposition of the yellow pigment called lipochrome in the iris (which is also found in green eyes). ![]() Amber eyes in sunlight – displaying an orange color rather than brownĪmber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint.
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