Sorry, this is not me, this is Google.
Slavs-Aryans (RASA) consist of 4 peoples - differences, incl. by the color of the eyes - the iris reflecting the spectrum of the Solar System from which that people originally came out.
Rasens are the third Genus. In world history, their descendants are called Etruscans. The appearance of the Rasens was as follows: height up to 270 centimeters (that is, lower than the Darians and Kharians), with brown eyes , dark blond hair color. The military skills of the Rasens were not so developed, since they did not live on the borders of the occupied territories. But the races in war are more violent and fierce, but less resistant to mental and physical influences. Rasens are very sensitive to the world around them. They made good priests and wise men. Modern peoples - descendants of the Rasens: Italians (residents of the Apennine Peninsula), Albanians, some Russians and others.
Four clans of the race arrived on Midgard-earth, these are Daryans, Kharyans, Rassen and Svyatorus, of which we are descendants.
Let's start with the fact that the iris consists of two layers: the front is mainly represented by the stroma of the iris with chromatophores containing melanin; the posterior is rich in melanin and, as a rule, dark. Fibers and vessels of the iris also play a role in chromaticity. The whole variety of color is encoded mainly by six genes (whose names will not tell you anything) - nih.gov - by which blue and brown colors can be predicted with an accuracy of 90%, and intermediate ones - up to 70%.
Blue, cyan and gray. Blue and cyan are rather strange colors of the iris, since there is simply no blue pigment in the iris. In such eyes, there is little melanin, there are few collagen fibers in them - they themselves are light, and with an increase in their number, blue eyes turn out to be blue, with an even greater number of eyes they will look gray or gray-blue, rather - steel. Chromaticity is caused by the scattering of light in the stroma, which then falls on the back shell, which contains a lot of melanin and has a black-brown color, as a result of which the low-frequency component of the incident light (close to red) is absorbed, and the high-frequency component (close to, in fact, blue) is reflected ... Moreover, the lower the density of the stroma, the richer the color. So: less collagen fibers and melanin - more blue, more collagen fibers - blue or, if there are more, gray.
Green. Green color is quite rare, because it is caused by the presence of a small amount of melanin, a uniformly distributed yellow-brown lipofuscin pigment in the iris, and when the blue reflected light and the light transmitted through the yellow pigment are mixed, the sum is green. However, it is intuitively clear that a uniform distribution that gives such a color is not always found.
Amber, marsh, nutty (yellow-green). Yellow-green colors are more common, because they are caused by the same factors as green, but the pigment in them is unevenly distributed, and there is usually more pigment in them quantitatively. Hazel eyes, for example, mine :)
Brown and black. The brown color is obtained due to the high concentration of melanin. Both high-frequency light and low-frequency light are absorbed, resulting in a brown overall. The most common color. As for black, this is the same brown, but with a much higher concentration of melanin in the iris. There is so much of it that even the eyeball can acquire a grayish or yellowish tint instead of the usual yellow. All incident light is absorbed.
Other colors and their combinations are explained either by pathologies or by wearing contact lenses.