03 3489728 Straven Road Vet
03 3525749 Papanui Vet
Progressive Retinal Atrophy (PRA)
by Dr. Francesca Matthews
What is the retina?
The retina is the tissue at the back of the eye that light reflects off. When light is reflected off the retina it sends little electrical impulses to the brain, which the brain interprets into a picture.
Where is the retina?
What is Progressive Retinal Atrophy (PRA)?
PRA is an inherited disease that causes progressive and irreversible blindness. The majority of affected animals are purebred dogs. The reason for this is that the disease is autosomal recessive which means it requires both parents to at least be carriers of the gene for the offspring to be affected.
If both parents are carriers, 25% of the offspring will have PRA and a further 50% will be carriers. If one parent has PRA and the other is a carrier, then 50% will be affected and the remaining 50% carriers. If both have PRA, all offspring will have PRA. If one parent only is a carrier, then 50% of offspring will be carriers and 50% non carriers. In that generation no puppies will be affected.
Image source wikimedia commons
What are the signs of the disease?
The first sign owners usually notice is night blindness. Over several months the blindness progresses, until the dog can no longer see during the day.
Why should I know about it?
If you are planning to breed from your dog, you should ensure that they are free from the disease. Read our article on responsible dog breeding.
If you are purchasing a pedigree puppy or purebred kitten you should do adequate research to ensure that the new puppy or kitten you are purchasing is free from the disease.
How is it diagnosed?
DNA testing is now becoming more available. This allows you to check whether an animal is clear from the disease, a carrier who will be unaffected (but can still pass the gene on to offspring), or an affected animal who isn’t yet showing signs, but will do in the future.
If DNA testing is not available in your area, then breeders should be ensuring their purebred breeding animals are checked annually by a veterinary ophthalmologist to check for the occurrence of PRA or any other inherited eye disease (of which there are many).
Choose your new puppy or kitten with care and due diligence. This should involve contacting one of our veterinarians for advice.