A basic characteristic of humans is their eye color. Whether brown, blue or green – this is also shown in the passport, among other things. But why do people actually have different eye colors?
Iris and pupil
The iris or iris skin is the colored part of the eye and is virtually an aperture for the eye. It controls the incidence of light: in brightness, it narrows – so the incidence of light is reduced. The iris thus acts like the diaphragm of a camera. The activity of these muscles is controlled by nerves and happens unconsciously for humans.
The pupil is the opening in the iris that allows light to enter the interior of the eye. In high brightness the pupil is smallest (1.2mm) and in darkness it is largest (9mm).
So how does the color of the eyes come about?
The pigment melanin, which also determines the tint of skin and hair, is responsible for eye color. Depending on how much pigment is stored in the cells, the eyes also get their individual color.
A high concentration of melanin results in brown eyes; these people usually also have darker skin than others. Conversely, it is rare to see someone with dark hair and blue eyes. A lower pigment content makes the iris appear green, blue or gray, depending on the dosage. The less melanin, the bluer eyes a person has.
As babies, we tend to have blue eyes….
The final color is genetically predetermined. In the womb, the iris is still light blue and only later reaches its full coloration. The reason: the pigment develops in the body only in the first years of life. This means: with increasing age, the eye color also changes.
Eye color – an unchangeable characteristic
If this process has then come to a standstill, our eye color also always remains the same. So whoever has brown eyes can no longer get blue ones, and vice versa, blue-eyed people also have blue eyes all their lives.
By the way, if you still want to try a different eye color, you have this option with the so-called iris lenses.