Answer:

In fact, these tiny foreign bodies have two main ends, one of which many people can think of, is to be brought out in tears. When a foreign body enters the eye, it will attract the attention of a large number of sensitive nerves distributed in the corneal layer of the eye. Then the lacrimal gland begins to secrete tears and at the same time blinks to bring the foreign body out with the tears.

In addition, the composition of tears includes inorganic salts, lysozyme and other substances, which can moisten the eyeball while killing bacteria and disinfecting the eyeball. Speaking of this, I remember when I was a child, my eyes got sand in them, my parents would help me blow my eyes, because in the process of blowing my eyes, they would dry out, secrete a lot of tears, and the feeling of foreign objects would disappear after a while.

The second result is that the foreign body will become part of the stool, which can be eye stool (mucus) or nasal stool. We just said that the cornea of ​​the eye has a large number of sensitive nerves, in the area under its jurisdiction there is a lump of sand that cannot be rubbed into the eye, it must be driven away. But in the process of rubbing the eye and blinking, foreign bodies can run to other areas. Because there are fewer sympathetic nerves in those areas, it is difficult to sense the presence of foreign bodies.