Progressive Retinal Atrophy (PRA) is an inherited disease that affects eyesight in Labrador Retrievers and several other breeds. It causes degeneration of the retina which is where light is changed into electrical signals and sent to the brain.
PRA is not painful but affected dogs will go blind.
There are several forms of PRA in dogs, and Labs have the prcd-PRA form. The PRCD part stands for progressive rod-cone degeneration and is caused by a mutation in the PRCD gene.
Affected puppies are born with normal retinas, but over time the cells break down which causes the blindness. When that happens varies however it often starts when they're about three to five years old.
The rod cells - helpful with night vision and motion detection - generally break down first. The cone cells - helpful with color detection - will break down next, ending with complete blindness.
You may not notice it right away because dogs adjust very well. It is more noticeable after dark or when the dog is away from home. Some signs include:
- bumping into things
- hesitating to use stairs
- seeming disoriented
- reluctant to go outside after dark
- dilated pupils
PRA is a preventable genetic problem.
Annual eye exams by a veterinary ophthalmologist can detect a variety of eye problems. Early detection may make a difference in some diseases.
However, you can have your dog tested with a simple test. Get a few sterile swabs (they look like a long q-tip). Wait an hour after your dog has eaten, then wash your hands and position the swab between his cheek and gums. Swirl it ten times and place the swab back in the packaging. Repeat with another swab inside the other cheek. Package and mail the swabs to a laboratory that does genetic testing for dogs.
I use DDC and like that they're polite, fast, and reasonably priced. They offer a variety of genetic tests, and you can do several tests or just one at a time. They'll also send you a packet of swabs if needed.
About two weeks later, you'll get an email with the results. Dogs that are clear of the mutated gene are not at risk and will pass clear genes to their puppies. Labs having one copy of the mutated gene are not at risk but may pass that gene to puppies. Labs having two copies of the mutated gene will gradually go blind, and all of their puppies will have at least one copy of that gene. There is no cure.
If you plan to breed your dog, this is one of the tests you should do. Finding out whether your dog is clear, a carrier, or affected will help avoid producing puppies with prcd-PRA. An exception would be if both of your dog's parents were tested clear AND you have copies of those results.
Prevention is as easy as choosing at least one parent tested clear of PRA.
HELPING A BLIND DOG
If your dog has two copies of the mutated gene, he will gradually go blind. Dogs generally accept it much better than people do, but you'll want to help him cope anyway.
Be aware that blind dogs may become disoriented and anxious. Losing sight can also reduce his quality of life if he can't do some of the things he enjoyed doing.
Start helping him by fencing off potentially dangerous areas, such as:
- long flights of stairs, indoors and outdoors
- holes and steep slopes
- cactus and other similar plants
If you have any remodeling plans, try to finish that while your dog can still see. Do the same with rearranging furniture.
You may notice he doesn't see as well in dim light. If so, provide additional lighting if you can.
Keep your dog's bowls and crate or bed in the same spots.
Add tactile and/or scent clues so he can find his way. For example, add throw rugs in front of furniture and gravel or wood chips in front of bushes. Spray a particular scent near his bowls and another scent on his bed. Always use those same scents in each location.
If he likes toys, get some that make sounds. A giggle ball can be particularly fun.
And best of all, talk to your dog. He may jump if he doesn't know you're about to touch him, so talk or make some noise first. When calling him to come to you, don't just say it once, continue speaking so he can find you. He can also learn cue words, such as "watch out" and "step", to help him navigate.
Even if your dog has been tested for PRA, an annual eye exam is a good idea. Other conditions can affect vision and overall eye health.
Some of the most common eye problems in Labs include:
- Cataracts: a clouding of the lens in the eye, which can cause vision problems or blindness. Labs are prone to developing juvenile cataracts, which appear before the dog is a year old.
- Retinal Dysplasia: a developmental disorder that affects the retina, and can cause vision problems or blindness. This is another hereditary condition in Labs.
- Corneal Dystrophy: a group of genetic disorders that affect the cornea, which can cause vision problems or corneal ulcers. Labs can be affected by epithelial/stromal corneal dystrophy.
- Glaucoma: a condition that causes increased pressure within the eye, which can damage the optic nerve and cause blindness. Labs are prone to developing glaucoma.
- Entropion: a condition where the eyelashes rub against the eye and cause irritation. Labs are prone to developing entropion.
Dr. Becker Discusses Blindness in Pets
PRA is a significant health concern in Labs. There is currently no cure for PRA, but genetic testing is quick and easy.
If you're planning to breed your dog, have him or her tested. Ensure at least one potential parent is clear of PRA.
If you're considering buying a puppy, check if the parents have been tested clear. Check for proof, not just that they've been cleared by the local vet.
No dog should go blind because of PRA.