Rats eyes

Question
We have a white rat and we noticed today that his left eye ball is swollen. There is no blood or pus just swollen. It's alot bigger then the other eye, Can you tell me what this could be and what we can do for it?

Answer
Is this recent, or has it been happening for awhile? Is his eye becoming milky, or does he act as if he can't see out of it? It could be an abscess or tumor pushing on the eye, he may have injured his eye and have some swelling; or it could be the start of a respiratory infection symptom. I recommend a vet.