According to Nicholas Dodman, Director, Animal Behavior Clinic, Cummings School of Veterinary Medicine, Tufts University.
Keep an Eye Out
Poor vision should be addressed by a veterinarian, who will be better able to determine the cause. While the graying of dogs' eyes with advancing age may look as though it is affecting the dog's vision, it isn't. On the other hand, cataracts or retinal degeneration can render a dog virtually blind.
Tell the Furniture to "Stay"
If a dog's sight is fading, it's best to keep things in the same place as much as possible so that the dog can work from memory, in conjunction with what remains of her vision, to navigate the environment. Bright lighting will help some dogs assess things more clearly, though those with cataracts see better in dim light, when their pupils dilate, allowing them to see around the cataract.
Now Hear This
A medical check may reveal an auditory problem to be as simple as wax buildup in the ear canals or as serious as canine cognitive dysfunction (CCD), a condition similar to Alzheimer's disease. With CCD, it is not that affected dogs don't hear, they just can't process the incoming signals properly. When dogs with this condition who exhibited apparent deafness were treated with a drug called L-deprenyl, a number of them showed improvement in mental acuity, suggesting an improvement in hearing.
Speak Up -- or Try a New Collar
If a dog has indeed lost much of her hearing, make the necessary allowances, such as talking to her in a louder voice. When you're outside, a shrill whistle may work better than a vocal command. Some owners communicate with totally deaf dogs by using a form of sign language. Others have success with a remotely operated vibrating collar: When it's time for dinner, for example, they press the button on the controller and a vibration signals to the dog that the meal is ready. Sadly, some dogs eventually become completely deaf or blind. But as long as they continue to enjoy food, petting, and attention, they still have plenty of things to live for.