Anyone know of a natural/homeopathic way to treat an eye infection in a cat?

Conjunctivitis is a symptom not a disease. It simply refers to the fact that the eye membranes (conjunctiva) are red and swollen. It can be either viral (like herpes) or bacterial. Without knowing the cause - and treating the underlying problem - no natural./homeopathic remedy is going to reliably fix the problem. If you don't know what the problem is, how can you treat it? Herpes especially, left untreated can cause the loss of the eye. Your cat needs to see a vet - sorry.