Progressive Retinal Atrophy
An Inherited Cause of Blindness in Dogs
“With a little help from their owners, affected dogs can continue
to enjoy an excellent quality of life.”
Progressive retinal atrophy (PRA) is a genetic condition that causes poor vision and blindness in dogs. Several forms of the disease exist but no treatment exists for any of them. With a little help from their owners, affected dogs can continue to enjoy an excellent quality of life.
Overview/Snapshot of the Disease
As the name suggests, progressive retinal atrophy is a disease that affects the retina, the tissue lining the back of the eye that contains photoreceptors. These specialized cells are responsible for converting light energy into electrical nerve signals, which then travel through the optic nerve to the brain where they are perceived as vision.
There are two types of retinal photoreceptions – rods and cones. The rods are responsible for black and white vision and are most important in low light conditions, while the cones are responsible for color vision and are active in bright light.
When a dog has PRA his photoreceptor cells deteriorate and stop working over time.
The condition usually first affects the rods and then the cones, which is why affected dogs generally first have problems seeing in the dark.
Symptoms of PRA in Dogs
Because dogs are so good at compensating for lost vision, owners may not observe any symptoms until PRA is quite advanced. The first sign usually noticed is poor vision in dim light. You may find that your dog is unwilling to enter a dark room or stairway or does not want to go outside after sunset.
As the disease progresses, a dog’s ability to see when it is bright also decreases. In familiar surroundings, the pet may still be able to navigate through a room or yard extremely well, but if something changes or is new, he may bump into things or not want to move around much at all.
Causes of Progressive Retinal Atrophy
PRA is one of many inherited dog diseases. The list of susceptible breeds is very long, but some of the more popular dogs that can carry the genes for PRA are Labrador Retrievers, Poodles, Cocker Spaniels, Collies, Irish Setters, Dachshunds, Miniature Schnauzers, Akitas, Australian Shepherds, Golden Retrievers, Samoyeds, Beagles, German Shepherd Dogs, Siberian Huskies, Yorkshire Terriers and Portuguese Water Dogs.
Mixed breed dogs rarely develop progressive retinal atrophy. If your dog has PRA, do not blame yourself. Nothing that you did or did not do is responsible for his condition.
Progressive Retinal Atrophy Treatment
A veterinarian or veterinary ophthalmologist can often diagnose an advanced case of PRA in dogs with a thorough eye exam. Earlier in the course of the disease, however, a test known as an electroretinogram (ERG) is necessary. If your veterinarian is concerned that other systemic or ocular dog diseases could be to blame for your dog’s poor vision, additional tests may be necessary.
Unfortunately, there is no treatment for PRA in dogs, and most with the disease eventually become blind. An owner can do a lot to help a dog with progressive retinal atrophy, however.
Try to keep the dog’s surroundings as consistent as possible. Food and water should always be offered in the same location. If you do need to move furniture or make any other similar changes, do so as gradually as possible. Close doors or place baby gates across the openings to stairwells, decks, or balconies to prevent falls.
Blind dogs can still go outside in a fenced back yard, but make sure that they cannot access any bodies of water. Leash walks are often still enjoyable, particularly along a familiar route.
Prevention of PRA in Dogs
The incidence of progressive retinal atrophy can be decreased by selectively breeding individuals that do not carry the genes for the disease. For over 40 breeds, a blood test is available that is used to identify which dogs should be bred and which should not.
If this genetic test is not available for your breed, yearly ophthalmologic exams and clearances issued by the Canine Eye Registry Foundation (CERF) are the next best things. Only buy purebred puppies from breeders that have done all they can to reduce the incidence of genetic dog diseases in the breed.
Dogs that develop PRA or carry the genes for the disease should be spayed or neutered.
Consulting Veterinarian: Jennifer Coates, DVM