how do you know if your dog is going blind?
Actually, if you're talking about an older dog, you really can't tell they are going blind, except by the cloudiness in the pupils. Dogs use their noses, in the same way as we use our eyes...in familiar territory, you might never know your dog has lost it's sight...and a"half-blind" dog would appear to have ALL it's sight.
I'd think that if you think the dog is going blind, because it bumps into things, misses movement (like when you walk, or cat runs), that it's already totally blind.
What symptoms make you think your dog is losing it's sight?
Someone asked the same question about a year ago on this site. Here is the link and also another link that might be helpful.
Usually if you see a sort of fogginess in it's eyes that stays there, one way to tell...
call for it put something in front of it and see if it walks into or around it
there eyes get all foggy and blu
blue-ish eyes and less alert ..