What did the vet say is causing this?
Blind dogs adjust amazingly well. Unlike us, they don't mourn the loss and just accept what "Is".
Actually, sight is not nearly so important to dogs as their senses of smell and hearing. The fact that your dog is losing sight slowly will make it easier for her to adjust.
Once the dog has learned to navigate and where things are, you often can't tell they are blind at all. We had a husky in our rescue who had to have both eyes removed. He was adopted and is a very happy and well adjusted dog, and it's very difficult to tell he can't see!