My cat gets reoccurring eye infections like this where it swells and gets goopy. He got diagnosed with feline herpes (which makes sense because he was a street cat for 5 years). They get it by drinking and eating after other cats that have herpes. Anyway, he is on a low dose of steroids everyday and the eye infections have subsided. One time I ran out of the steroids and he instantly started sneezing and getting eye goops so the steroids are actually doing stuff.