1. High salt content in the diet
If a cat's diet contains too much salt, exceeding its metabolic capacity, it will be excreted through other channels. This includes the nasolacrimal duct system; if the nasolacrimal duct is blocked, it can cause excessive eye discharge in cats. Therefore, it's important to choose a nutritionally rich, low-sodium diet. 
2. Eye inflammation
This is quite common. Free-roaming cats are likely to develop eye injuries due to fighting, leading to inflammation and excessive tearing or eye discharge. Alternatively, it could be an eye infection caused by insect bites.
3. Variety Issues
For example, Garfield cats and Persian cats are born with short tear ducts, so it is common for them to have excessive tearing and eye discharge. In the absence of a pathological condition, frequent cleaning is sufficient.
4. Inflammation inside the eye
When cats are infected with conditions such as dacryocystitis, conjunctivitis, or blepharitis, they will have yellowish-green eye discharge and their eyes will water frequently. In such cases, medication is necessary; antibiotic eye drops are sufficient.
5. Caused by infectious diseases
In addition to the reasons mentioned above, similar symptoms can also occur when cats are infected with infectious diseases, such as feline rhinotracheitis and feline panleukopenia. Further examination is required for specific diagnosis.
6. Cleanliness of living environment
A cat's living environment is very important; try to avoid dust and irritating odors that may bother the cat.
