Natural diets are very helpful to any animal with vision problems.
Fresh carrot juice can be a great source of carotenes for dogs; the book "how to have a healthier dog" talks about veterinarians that use vitamins A & E, along with the mineral selenium for cataracts in dogs. Supplement also with a good quality vitamin C with bioflavonoids and trace minerals. Minerals are important because the eyes use more zinc than any other part in the body.
Dogs don't need to talk, their life is their message ~ unknown.
"The greatness of a nation and its moral progress can be judged by the way its animals are treated." ~ Mahatma Gandhi