In winter, we feel the biting wind and cold hands and feet. Many people’s ears and noses are prone to frostbite in the cold season, but the eyes that are also exposed on the body are not afraid of cold. Even though the eyebrows are frozen and the eyelashes are frosted, the eyes are still looking forward freely without any cold feeling at all. Why are the eyes not afraid of cold?
Normally, as long as the big needle-point particles fall into the eyes, the eyes will feel tingling and uncomfortable. This shows that the eyes are the most sensitive part of the body for pain, and the eyes have nerves that sense touch and pain.
The structure of the eye is quite strange. The cornea, conjunctiva, and sclera that make up the eyeball are rich in touch and pain nerves, but they lack the nerves to sense cold. More importantly, the cornea and sclera are composed of avascular transparent connective tissue, which has almost no heat dissipation effect, but can play a role in buffering the conduction of cold to the eyeball. In front of the eyeballs, there are eyelids rich in blood vessels, which block the cold wind like two doors. So even though the eyeballs are exposed, no matter how low the temperature is, they are not afraid of the cold.
