There are various forms of PRA and each form differs in its age of onset and the rate by which it progresses. Some breeds of dogs may develop PRA early in life while there are other breeds wherein PRA develops later in life.
The photoreceptors which are located in the retina of the eyes normally develop after birth and until the puppy is around 8 weeks old. Dogs suffering from PRA often have Retinal Dysplasia or the early deterioration of these photoreceptors. Dogs suffering from Retinal Dysplasia early in life, 1-2 months after birth, may become completely blind by the time they are one year old.
Since PRA is a progressive disease, it can worsen as time passes by. At the early stages, an affected dog may first experience night blindness particularly when the rods are affected first. As the condition progresses, the affected dog may also suffer from failed daytime vision.
The manifestations of Progressive Retinal Atrophy are dependent on the type of PRA and the rate of progression in Beagles. Although it is not a painful condition and the eye may appear normal, dog owners usually notice a change in their dog’s behavior particularly when going down stairs or passing a dark hallway. This behavior is typical with night blindness and may improve during daytime. As the condition progresses, the affected dog may experience dilatation of the pupils. In cases where the disease progresses slowly, a dog owner may fail to see any signs of vision loss except in unfamiliar surroundings where the dog’s lack of vision becomes more noticeable. There are also cases of PRA where the lens of the eyes appears opaque or cloudy.
Progressive Retinal Atrophy can be diagnosed by a veterinary ophthalmologist who will perform a thorough ophthalmic examination and in some cases electro-retinography. Tests will reveal characteristic changes and lesions in the retina and other structures of the eyes. Both tests can be performed without anesthesia since it is a relatively painless procedure.
There is no successful treatment for PRA and animals suffering from the condition usually become blind. There is also no successful way to slow down the progress of the disease however dogs can easily adapt to progressive blindness and changes in behavior may not be as obvious when they are in their own environments. Blindness or any loss of vision can be more noticeable when the dog owner rearranges the furniture or takes the dog to unfamiliar surroundings.
Since many cases of PRA have been linked to genes, affected animals should not be allowed to breed and should be neutered or spayed. If your puppy has developed PRA be sure to notify the breeder.