1. Why the eyes don't freeze
Eyes never freeze, because there are no nerve endings that are sensitive to cold (thermoreceptors).
2. Why the eyes don't freeze
Why the eyes don't freeze in the cold? In fact, the vitreous body of the eyeball consists of water at 99%, and the cornea (the outer surface of the eye) is always moisturized. It would seem, when the frost eyes should turn into a chunk.
Eyes very well protected from freezing. Factors that do not allow the eyes to freeze some.
First, the fluid that moistens the eye is not pure water, it contains salt. And salt water freezing point lower than that of pure water. High salt concentration in the tear allows it to not freeze even at -32°C.
Secondly, in our body has a powerful system of thermoregulation, which starts to work every time, when the ambient temperature differs from the optimal. Eyes abundantly supplied with blood capillaries, and, when the temperature of the blood flow in them increases, bringing the eyes of the additional heat and not allowing them to freeze.
Thirdly, the eyeball is well protected from damage from the environment: a large part of which is located in a recess in the skull - orbit, and on the outside to hide behind his eyelids.
Eyes can freeze, but it will require a very low temperature. For example, in medicine we use the technique of retinal cryotherapy - removing regions of the retina with liquid nitrogen (boiling point -195,8°C).
