Progressive retinal atrophy (PRA for short) is an umbrella term for a group of inherited conditions that affect the retina leading to progressive loss of sight and eventual blindness.
Inherited conditions result from puppies bred from parents that carry a damaged gene. Genes provide crucial information for every aspect of the body’s structure and function, as well as what may be passed from parents to offspring.
Let’s take a look at the details about the condition, what breeds are most likely to get PRA and how to best adapt your dog’s day-to-day life if if they have succumb to this disease.
What Is The Retina?
First, let’s think about the retina in a healthy animal. The retina is located at the back of the eyeball. When light passes through the pupil at the front of the eye, it hits the retina, triggering special cells that react to light – photoreceptors. These photoreceptors cause nerves to fire, passing the message to the brain. The brain then interprets these signals as an image. This is how we see, and it’s the same for our pets.
What Is PRA In Dogs?
The term ‘atrophy’ means “decrease in size or wasting away of a body part or tissue”. The acronym PRA refers to the gradual deterioration in the retina’s photoreceptor cells. As the number of cells at the back of the eye decreases, so does the amount of information sent from the eyes to the brain. This results in a gradual but eventual complete loss of sight.
There are broadly two recognized types of PRA. The first is early-onset progressive retinal atrophy, also called retinal dysplasia. It is usually first noted in puppies around two to three months. The other form is late-onset PRA, and dogs typically show signs between three and nine years old. There are several subcategories of PRA that your dog might be diagnosed with – your ophthalmologist can explain this in more detail.
What Dog Breeds Are Most Likely To Have PRA?
PRA can affect any dog, but some breeds are more commonly affected than others, and this varies with the type of PRA:
- The late-onset version is more common in Miniature and Toy Poodles, Cocker Spaniels, and Labrador Retrievers. Other more commonly affected breeds include Tibetan Terriers, Longhair, and Wired-haired Dachshunds, amongst several others.
- Retinal dysplasia is most common in Norwegian Elkhound, Irish Setter, Collies, and Miniature Schnauzers.
Dog DNA tests can also help you gain a better understanding of your pet’s hereditary health concerns like PRA as well as get a firmer grip on their breed makeup.
How Does A Dog Get PRA?
Usually, both parents need to carry the broken gene for the puppies to be affected by the condition, but PRA has some other subtypes with different inheritance patterns. For example, in Samoyeds and Siberian Huskies, only male puppies in a litter are affected if the mother carries the gene. In some Mastiff breeds, only one parent needs to have a faulty gene for the puppies to be affected. This is because the genetic information differs between the different types of PRA, so the inherited problem also differs.
What Are The Symptoms Of PRA In Dogs?
PRA is not a painful condition. The signs of the disease are usually associated with loss of sight, and it is often first noticed in darker conditions – termed “night blindness.” You may find your dog becomes reluctant to go into a dark room or starts to bump into things. However, your pet may act normal at home and just become increasingly clumsy in new environments.
The retina may become more shiny than usual, which can be seen from the outside of the eye when light shines through the pupil. You may also notice that your pet’s pupils become more dilated. The signs of PRA usually develop over a few months to a few years.
How Is PRA Diagnosed?
Progressive retinal atrophy can be diagnosed by a veterinary ophthalmologist (the specialist term for a doctor who works with eyes) or a general practicing veterinarian who has additional training in eye disease. If your veterinarian is concerned about other sight loss causes, they may recommend further testing such as blood tests, blood pressure measurements, or advanced imaging (such as CT or MRI) of your pet’s head. However, if there is a high likelihood of PRA, these additional tests are not needed.
In some cases – for example, if your pet has cataracts – it is impossible to see the retina at the back of the eye. In those cases, it may be necessary for your pet to have a short general anesthetic for a special procedure called an ‘electroretinogram.’ This measures the retina’s electrical activity.
Can PRA Be Treated?
While there is lots of active research into this field, there is sadly no treatment for PRA in dogs at the moment. Instead, the focus is on managing your dog’s lifestyle so they can still live life to the fullest.
Is It Fair To Keep A Blind Dog Alive?
This is a question that we, as veterinarians, are asked a lot. Many pet parents worry it is cruel to keep a blind pet alive, but dogs and cats can cope very well without sight. If you speak to any veterinary ophthalmologist, they usually agree it’s fair to keep a blind dog alive. PRA is not a painful condition, and the vast majority of pets adjust well and live full and happy lives. This is especially the case with PRA, as the loss of sight is often gradual, allowing your pet to adjust to its new normal. Often you find that your pet’s other senses become more enhanced to help cope with the loss of vision.
How Can I Best Look After A Dog With PRA?
It is important to keep your pets’ home environment constant. Most can form a mental map of their environment, remember the furniture locations, and even navigate the stairs. Ideally, try not to move furniture or food and water bowls around, as this confuses your pet. It can be helpful to use scent-impregnated or tactile aids (such as course mats) around the house. These can help your pet to orientate themselves. It can also be beneficial to leave the TV or radio on when you are out of the house, both for comfort and spatial orientation.
Take things slowly with your blind pet. When approaching your dog, talk to them soothingly so that you don’t startle them. You should also make sure any children visiting the house or approaching your pet are aware and follow the same routine. Even a dog with perfect manners can snap if startled.
You’ll need to take some important safety steps. Provide barriers around hazards like swimming pools or balconies. Stair gates can help stop accidents on the stairs. Padding corners of sharp furniture may also help.
Out And About
It is important to keep your dog on a leash when walking to provide reassurance and to prevent injury. The use of positive reinforcement, such as treats, and increasing your dog’s voice command repertoire can also help develop their confidence. It can also be helpful to use a warning on your dog’s lead or harness to make other members of the public aware that your dog is blind. If you are worried or unsure, seeking advice from your veterinarian or an appropriately qualified behaviorist can be invaluable.
How To Prevent PRA In Dogs
Since PRA is a hereditary condition, breeders shouldn’t include affected animals in their programs. There are now screening blood tests available for some breeds of dog, which can help identify those that are likely to develop the condition and those that carry the broken gene but do not go on to develop the disease. These ‘carriers’ can pass the gene to their puppies and should not be bred with other carriers.
What About Cats?
Cats are also affected by PRA. The clinical signs and diagnostic approaches are similar to those in dogs. Sadly, as with dogs, there is no treatment. However, cats should always be checked as other causes of sight loss can have similar symptoms.
Overall, although it can seem very daunting to know your pet is going blind. Rest assured that dogs with PRA can live happy lives. You may need to make a few adjustments to your routine to help them learn how to manage their new normal. If you have any concerns or questions, contact your local veterinarian, who can talk through how to help your pet best.