Not sure if you've heard of/read about the use of Apple Cider Vinegar to treat some pet maladies. I've excerpted this from a great site Earth Clinic Folk Remedies specifically the Apple Cider Vinegar for PETS section:

Marcella from Petaluma, CA writes: "ACV for Cats: Three Cheers! My seven-month-old rescue kitty came into my home with an upper respiratory infection and later developed some conjunctivitis in his left eye. Following the advice on this page, I gave him a dropperful of ACV right into the fur on the nape of his neck and massaged it down into his skin. Some of the liquid ran down the sides of his neck, where he licked it off. Within 90 minutes of his first dose, the conjunctivitis started to clear up, and his energy perked up considerably. He is now free of both the upper respiratory issue and the eye infection, with no vet visit needed. I know give him a maintenance dose every few days and yes, he's a little stinky from the vinegar, but happy and healthy nonetheless. I've also started taking the ACV myself. Good stuff."

I use ACV on the scruff of the neck for both of my cats for a couple months now and have had great success with no more weepy eyes.

Perhaps others will stop by and offer additional suggestions.