Dogs are susceptible to many of the same eye diseases and conditions as humans. For the most part, if your dog gets a good diet and plenty of exercise it won't have any problems. One exception is cataracts, which are fairly common among older dogs. Unlike humans, dogs rely on their senses of smell and hearing more than sight. Even if cataracts develop in one eye, the animal can probably get around just fine. Cataracts that affect both eyes can be corrected by surgery. Your dog's sense of hearing is more important, which is why its ears are bigger than ours. That means there's a fairly big space for various critters to sneak in and cause problems. One of the most common difficulties is caused by mites, tiny creatures that make a home in a pet's ears. Their bodies are covered by tiny hairs that can irritate a dog's ears and lead to serious infections. If your puppy is shaking its head or scratching its ears a lot, mites could be the culprit. A strong case of doggy B-O is another indication. An examination and treatment by your veterinarian is the cure.