Progressive Retinal Atrophy (PRA)
WHAT IS PROGRESSIVE RETINAL ATROPHY?
PRA is an inherited degenerative disease of the retina. The retina is the tissue in the back of the eye that senses light, similar to a film in a camera. In PRA the retina is degenerating, resulting in gradual vision loss.
WHAT CAUSES PROGRESSIVE RETINAL ATROPHY?
As an inherited disease, PRA is passed on from parents to their offspring. In most breeds the disease is inherited by simple autosomal recessive mode. This means that neither, father or mother has to have the disease but may simply be carriers. PRA is similar to the inherited disease Retinitis Pigmentosa in human beings.
ARE CERTAIN BREEDS OF DOGS PRONE TO PROGRESSIVE RETINAL ATROPHY?
Yes. The American and English Cocker Spaniel, Miniature Schnauzer, Labrador Retriever, Miniature Poodle and many other breeds are prone to PRA. It is also found in mixed breed dogs.
HOW DO I RECOGNIZE THAT MY PET HAS PROGRESSIVE RETINAL ATROPHY?
Initially you may notice that your dog has problems navigating in dim light conditions. Some dogs develop an aversion to go outdoors at night. Poor dim light vision eventually progresses to vision loss in all light conditions.
HOW IS PROGRESSIVE RETINAL ATROPHY DIAGNOSED?
In advanced cases, a veterinary ophthalmologist is able to diagnose PRA by examining the retina with an ophthalmoscope. If the disorder is not advanced, an electroretinogram (ERG) is helpful for diagnosis. This is a test of the retina similar to an echocardiogram of the heart. A contact lens electrode is placed on the topically anesthetized eye. The electrical signal produced by the retina after a light is flashed into the eye is measured with a computer.
IS THERE A TREATMENT FOR PROGRESSIVE RETINAL ATROPHY?
Currently there is no treatment for PRA. Dogs will generally adapt to their vision loss easily especially with your help. A great resource is Carole Levin’s book “Living with blind dogs.” Fortunately, PRA is not a painful condition. Dogs with PRA may develop cataracts. In these cases, cataract surgery is not recommended, since this will not improve vision.
SHOULD I BREED MY DOG IF IT HAS PROGRESSIVE RETINAL ATROPHY?
No. PRA is a genetic disease.
Dogs with PRA are amazing in memorizing their surroundings. They live very happy lives!