
I think with eyes I would normally pay my money and go and see the vet. If the redness is mild, I usually treat it myself first for a day or two with eyebright solution to see if it clears up - if there's squinting, then I'm going to need the vet's help straight away, particularly if there is any discharge.
My old girl tended to be a bit prone in her youth (big round eyes and bracken don't mix), and I knew to take her sooner rather than later.