We put a powder in our dog's food called Angels Eyes. The vet recommended it and it has helped dramatically to stop his eye drainage and redness. We buy it at the pet store and it is rather expensive but seems worth it to us.

What kind of shot?

I have a 13 year old chihuahua mix that has had the same problem. I give her 50 mg of vitamin c each morning and it takes care of it. There is no rda for vitamin c in dogs. They supposedly produce it in their liver; maybe some dogs don't produce enough. The only caution I'd give - a little is enough - so don't give too much or more than is reasonable (Don't mega dose).