Retinal Disorders. “Progressive retinal atrophy” (PRA) is the name for a group of conditions in which rods and cones die off; there is no treatment. Dogs who get PRA do so because they’ve inherited a defective gene. Although PRA strikes more than 100 breeds of dogs, different genes are responsible. Therefore, breeds differ in the age at which the condition appears, how fast the condition progresses, and the ratio of males to females among affected dogs. PRA appears during puppyhood in the Cardigan Welsh Corgi, Cairn Terrier, Collie, Gordon Setter, Great Dane, Irish Setter, Miniature Schnauzer and Norwegian Elkhound. In contrast, some breeds usually don’t develop PRA until adulthood. These include the American Cocker Spaniel, English Cocker Spaniel, Labrador Retriever, Lhaso Apso, Miniature Poodle, Portuguese Water Dog, Tibetan Spaniel and Tibetan Terrier. PRA occurs mostly in males in the Siberian Husky and Samoyed. Genetic tests for PRA are available for several breeds.
Other retinal problems include detachment of the retina from the back of the eye, inflammation and abnormal development. Causes include infection and injury. Some retinal disorders have no treatment, while others can be helped by surgery or treatment of the cause.
Dr. Vainisi, a pioneer of veterinary retinal surgery, treated movie star Benji for a detached retina in 2004. Another small dog, a Shih Tzu with two detached retinas, was his first case in 1985. “This was the love of her [the owner’s] life, this little dog,” Dr. Vainisi says. He asked the owner to bring the dog to Grand Rounds at the medical school at the University of Illinois at Chicago, where he was a faculty member. None of the ophthalmologists were willing to tackle the case because the retinas were completely detached and the procedure would be very difficult. But afterward, one of the ophthalmology residents volunteered to help. He came to Dr. Vainisi’s clinic the next evening with equipment for human retina surgery borrowed from the university, and they operated. “Within a matter of a couple of days, the dog got his vision back. It was really like a miracle,” Dr. Vainisi says.
It’s no coincidence that both these cases involved small dogs. According to Dr. Vainisi, several small breeds of dogs, including Boston Terriers, Jack Russell Terriers and Shih Tzus, love to pick up toys and shake them hard. “Fluid goes violently back and forth in the back of the eye, and it just rips the retina right off,” he says. “One moment they’re seeing, and the next moment they can be totally blind.”
Time Is of the Essence
The best way to protect your dog’s vision is to catch eye disorders early, when they are most easily treated. A dog with eye or vision problems may paw at or scratch his eye, squint, bump into things, become afraid of the dark, or be frightened in situations that did not frighten him before. The eye may produce discharge, be red, look cloudy or be swollen. The nictitating membrane may partially cover the eye.
If your dog seems to have an eye problem, take her to the veterinarian right away. Your vet may have the knowledge and equipment to diagnose and treat the problem immediately; if not, she may refer your dog to a veterinary ophthalmologist, a specialist in animal eyes and their disorders.
“Veterinary ophthalmologists do a one-year general internship and then a three- to four-year residency with board-certified ophthalmologists, seeing nothing but ophthalmic cases,” says Ellison Bentley, DVM, Diplomate, ACVO, and clinical associate professor of comparative ophthalmology at the University of Wisconsin’s School of Veterinary Medicine. “After completing the residency, they must pass a board exam given by the American College of Veterinary Ophthalmologists to become board certified.”
As in other veterinary specialties, the veterinary ophthalmologists on the leading edge of their discipline are at universities. However, veterinary ophthalmologists who practice in the community keep up-to-date by going to conferences and attending continuing-education seminars.