Progressive Retinal Atrophy (PRA): A Cause of Blindness in Dogs

Could your favorite dog breed be at risk of early blindness?

More than 100 dog breeds carry an increased risk of progressive retinal atrophy (PRA). This matters, because your dream pup could be at greater risk of premature blindness.

So, is your favorite on the list?

Some of these at-risk breeds are hugely popular:

• American Cocker Spaniel
• Chesapeake Bay Retriever
• Dachshund
• English Springer Spaniel
• Golden Retriever
• Labrador Retriever
• Norwegian Elkhound
• Irish Setter
• Poodle (Miniature and Toy)

What Is Progressive Retinal Atrophy (PRA)?

Let’s start at the beginning by finding out what progressive retinal atrophy involves.

Actually, the clues are right there in the acronym:

• P, for Progressive: In this case, it means a gradual worsening.
• R, for Retinal: The retina is the light-sensitive layer at the back of the eye.
• A, for Atrophy: This means a wasting away or loss of use.

Add it all together and we get a gradual wasting away of the light-sensitive retina.

Initially, this leads to poor vision. But as the PRA gets worse, it causes blindness.

Progressive retinal atrophy is a hereditary condition, caused by a genetic mutation that is passed down from parent to puppy.

Some dogs with the genetic fault may lose their eyesight, while others remain unaffected but are “carriers” of the gene — which means they can pass the condition onto the next generation even though they don’t show signs themselves.

Progressive Retinal Atrophy: Why It Matters to You

Some conditions are rare and a pet has as much chance of developing them as you have of winning the lottery. Sadly, PRA is not one of those conditions.

In some breeds, 1 out of every 5 puppies has the gene coding for PRA. These 20%-ers include Poodles, Nova Scotia Duck Tolling Retrievers and American Cocker Spaniels. And would it surprise you to learn that 1 in 6 Labrador Retrievers has the gene for PRA?

This means those of you with certain purebred dogs, those of you thinking about getting a dog and those of you who are breeders all should be aware of progressive retinal atrophy.

Quite simply, if breeders test their breeding stock and people refused to buy puppies from untested parents, then the distress of this blindness could be wiped out within a few generations.

In addition, you should be aware of the signs of PRA so you can help your dog adjust if they do have failing eyesight.

No Treatment. No Cure.

Let’s get things straight: There is no treatment or cure for progressive retinal atrophy in dogs.

But rather than bury your head in the sand, it’s important to spot the early signs. By doing so, you can help your dog adjust, and make the most of their failing eyesight to learn new ways of coping in the home and out on walks.

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Signs That Your Dog May Have PRA

So now you’re worried. What signs should you be on the lookout for when it comes to progressive retinal atrophy in a dog?

For most dogs, this loss of vision is gradual:

• It starts as “night blindness” where the dog is spooked in the dark, refuses to move and is more clumsy in low light than in daytime.
• This progresses to subtle signs, such as bumping into objects, tripping on curbs, and being slow or hesitant on a new walk. The dog’s behavior may also change, such as being easily startled, behaving oddly around other dogs and not being able to chase a ball.

The super-observant pet parent may start to see signs such as the pupil (the dark part of the eye) staying large even in bright light (it should constrict right down). The pupil may be so big that you can look into the back chamber of the eye and see thin blood vessels threading across it.

In the final stages of PRA degeneration, the lens may develop into a cataract. The opaque lens blocks light passage to the retina and gives the eye a blue or milky appearance.

Here is a quick rundown of some of the symptoms of PRA in a dog:

• Loss of confidence at night
• Reluctance to walk
• Bumping into things
• Dilated pupils in bright light
• Exhibiting odd behavior around other dogs
• Easily surprised

How Old Are Dogs Usually When They Develop PRA?

This is a hard question to answer because there are many different genetic mutations that can cause progressive retinal atrophy. The age at which a dog’s vision deteriorates will depend on the specific type of mutation.

For example, Irish Setters often suffer a particular form that causes night blindness from as young as 3 weeks of age, progressing to full blindness by their first birthday. Miniature Schnauzers, on the other hand, often have a type of PRA that is detectable at 1 year old but takes another 3–5 years to progress to total blindness.

Sadly, what we can say is that PRA affects young to middle-aged dogs, and is not just a senior dog health concern.

Is PRA Painful for Dogs?

No. If there’s a bright spot in all this, it’s that progressive retinal atrophy is not a painful condition.

PRA is caused by wasting or degeneration of the light-sensitive rods and cones. Degeneration tends to be nonpainful, in contrast to inflammatory/degenerative conditions, such as arthritis, which are sore.

How Is PRA Diagnosed in Dogs?

A veterinarian can examine the retina with a magnifying instrument called an ophthalmoscope. This enables them to check the appearance of the retina, looking for telltale signs such as thinning of the retina or abnormal blood vessels.

These signs can be subtle. When in doubt, the vet will suggest referral to a veterinary ophthalmologist for a more detailed exam.

If a cataract is present, this stops the vet from seeing into the back of the eye. The trick is here to use a specialist test called electroretinography to map the health of the retina. Knowing whether or not the retina is working helps in determining whether it is worthwhile to remove the cataract.

Is There a Treatment for PRA in a Dog?

No. Currently, there is no treatment for progressive retinal atrophy.

However, this does not mean you shouldn’t seek a firm diagnosis — there are other conditions that cause blindness that can be treated.

For example, some forms of cataracts can be surgically removed, while conditions such as high blood pressure can be reversed and restore vision.

How Can You Help a Dog With Progressive Retinal Atrophy?

When you recognize the dog’s eyesight is failing, you can help them prepare for blindness.

For example, you can start retraining the dog to voice signals rather than hand signals, and add in commands that help them know they need to step up or brace themselves for going around a corner in a car.

You can also start encouraging the dog to use their other senses to adapt to their changing world.

• A simple idea is to hang a bell near the back door, so the dog knows how to find their way back inside.
• Another suggestion is to use different scents in each room (such as potpourri, essential oils or air fresheners) to act as scent sign posts to let the dog know where they are.

Just take extra care when you’re out and about. The dog is best kept on a long leash when out, which gives them a sense of freedom while keeping them safe.

Other tips for helping a dog with PRA include:

• Speak to the dog when you enter the room or before touching them. Make them aware you are there, since they may be easily startled if asleep or they don’t see you enter. In turn, this could lead to snappy behavior because they are frightened.
• Use dog toys that make a noise. This helps the dog work out where the toy is so they can play.
• Avoid rearranging the furniture, and keep your house tidy. A blind dog will know their way around a familiar layout but will bump into or fall over unexpected objects.

In this quick video, Dr. Eric Ledbetter, DVM, DACVO, discusses the importance of eye screening exams:

Thinking of Breeding? Get Your Dog Tested.

Be responsible and get any dog used for breeding screened — this includes both males and females.

Signs of progressive retinal atrophy might not be evident in a young dog, and just because they appear fine doesn’t mean they are.

Check out DogWellNet for the genetic tests available. In the United Kingdom there are various screening eye exams that should be done before mating.

And the final word goes to those thinking of buying a purebred puppy. Do your research into whether that breed is at increased risk of progressive retinal atrophy. If this is the case, then directly ask to see the breeder’s certificate stating that the parents have been screened and are clear from PRA.

If the breeder doesn’t have the paperwork, walk away. Likewise, don’t accept any hogwash about their lines have been clear for generations, or they are show dogs and have never had problems. Quite simply, they cannot prove the dogs are clear unless the dogs have been checked by a specialist.

Remember, breeding from animals that are verified clear of PRA will help eliminate this condition. Breeders work by supply and demand. If there is no demand for screening, they will continue to take the path of least resistance (which is also the most financially lucrative) by not testing. It’s when the public demands peace of mind and refuses to accept a compromise that we’ll finally get to grips with PRA in dogs.

So, what’s your favorite dog breed? Whatever the breed, ask questions — and in so doing, promote their long-term good health.

References

This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. This article was originally published in 2012 and is regularly updated. It was last reviewed for accuracy and updated June 16, 2020.

If you have questions or concerns, call your vet, who is best equipped to ensure the health and well-being of your pet. This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. See additional information.