Why do cats' eyes tear up?

The cat's eyes are infected by bacteria, viruses, or parasites.

Ingrown eyelashes and accidental conjunctival injuries, such as insects, foreign objects, or chemicals entering the eye, can all cause cats to tear up excessively. Dietary issues: If the food contains too much salt, it can also cause cats to tear up.

Conjunctivitis can also cause tearing in cats, and may even lead to more serious symptoms. If a cat's tearing starts gradually, with the eyes and surrounding area slowly becoming red and swollen, accompanied by abnormal blinking or squinting, and increased eye discharge, it is very likely that it has conjunctivitis.

Cats infected with feline herpesvirus not only often have watery eyes, but also have poor overall mental state, suddenly develop high fever, runny nose, decreased appetite, conjunctival hyperemia, photophobia with tearing, fluctuating body temperature, rapid breathing and heartbeat, small amount of eye discharge, and difficulty breathing.