Progressive Retinal Atrophy or Degeneration and Blindness in Dogs

Coping with Blindness

Question: Hi Dr. Richards,

I'm a new subscriber, don't quite know what to expect, but here goes.

My dog is a miniature poodle, age 13. Very healthy except that she has lost her vision because of retinal "degeneration" (I'm not sure that is the exact name of the condition.) She has lost her vision completely (I think) in the last 6 months.

My problem is that of not being able to help her adjust. I've done all the obvious things that need to be done for a blind dog. She has lost all her zest - is easily confused and when that happens she freezes. I've switched from collar to harness because I need to pull her when that occurs and don't want to hurt her. At bedtime, when she needs to be awoken to go outside and upstairs to the bedroom she is most confused.

I would like names of several books that I could read to help us through this situation.

Thank you, Ellen

Answer: Ellen-

We have had a blind dog but she adjusted very well to the blindness as she had progressive retinal atrophy and went blind over the course of a couple of years (more or less), so I don't have much personal experience to offer. I also am unaware of any books that deal with this subject, although it would not surprise me if there are some. However, I have found several web sites while searching for help for you and for other people who have asked similar questions that might be helpful:

http://www.eyevet.ca/blind.html

http://www.vin.com/PetCare/Articles/Dogs/PCF02672.htm

http://groups.yahoo.com/group/blinddogs

http://www.blinddogs.com/

In addition to this information, I have received a couple of reports from pet owners of the use of anti-anxiety medications for dogs with sudden onset blindness. The medications used were alprazolam (Xanax Rx) and diazepam (Valium Rx). The dog in which alprazolam was used responded reasonably well to the medication and the diazepam usage was less successful but the number of dogs (one) for each drug is way too small to know if it is valid information at this point. However, this seems reasonable to try if your dog is anxious or gets panicked by new situations due to the blindness.

It may be worth considering the use of selegiline (Anipryl Rx) to make sure that the confusion is not partially fueled by canine cognitive dysfunction, which also occurs as dogs age and leads to confusion and loss of normal habits or behaviors. In all likelihood this is not the case but it still might be worth a try.

Medications that have anti-depressant effects in humans, such as fluoxetine (Prozac Rx) are used for behavioral modification in dogs. No one really knows for sure if depression actually occurs in dogs but it seems reasonable to assume that it does and that circumstances like the onset of blindness would be reasonable times to consider the possibility that it is occurring. I don't think I would rule out using fluoxetine if the standard things like not rearranging furniture, keeping the food and water bowls in the exact same spot, talking to your dog to reassure it about your presence, putting bells on pets that might get in her way (or harass her) and things like this did not help her adjust by this time. I don't think that medications are necessarily the best or sole answer to the adjustment problems but I just wouldn't rule them out, either.

Mike Richards, DVM 10/17/2001

PRA /PRD more likely then Nuclear Sclerosis with night blindness

Question: I Have a 7 yr. Black Lab, night vision is almost gone, vet believes it's Nuclear Sclerosis or PRD

Answer: Christy-

Nuclear sclerosis would be an unusual problem to be causing visual problems at 7 years of age. Progressive retinal atrophy (PRA, might also be referred to as PRD) is fairly common in Labrador retrievers and is a more likely problem.

We have had a Lab who had this problem. She seemed like she was afraid of the dark at first but gradually it became obvious that she just couldn't see very well in the dark. Over the course of a couple of years she gradually become completely blind. Due to the long period over which this occurred she adjusted very well and it was difficult for most visitors to our house to tell that she was blind.

It would be a good idea to have an ophthalmologist examine your dog's eyes, to see if this is the problem, or to establish what the problem is. There are a couple of ophthalmologists who practice in your area, at least part time. Your vet should be able to refer you to one. This won't change things if the diagnosis is PRA, because there is no treatment, but it might make a big difference if there is another problem that can be treated.

Mike Richards, DVM 10/2/2001

Progressive Retinal Degeneration

Q: My lab may be diagnosed with Progressive Retinal Degeneration. (I'll know on St. Patricks day after the exam) He survived parvo at 7 months and now at 4.5 years he may be going blind. I am so upset. I understand it may be (is?) genetic. Does this mean since he got parvo it was activated? There are cataracts in both eyes which can be removed, but if he has the PRD then there is no reason. What can you tell me about this and/or where can I get info? Also, can my other dog be trained to assist my blind dog (does that sound a bit extreme?) I so appreciate your writing back, I'm out on a tether here.

Most Sincerely, Alice

A: Alice

I have personal experience with progressive retinal degeneration ( PRA) in a Labrador retriever. The very first dog that my wife and I acquired after our marriage was a mixed Lab named Shasta. She developed PRA and was blind for the last six years or so of her life. She adjusted to the situation amazingly well. Many visitors to our house never realized she was blind, even with the "Orphan Annie" eyes from the cataracts. Most of the dogs in our practice who have slow onset blindness adjust well and have few problems associated with the blindness so even though the situation seems very bad it may not be quite as hard to live with as you may think.

This condition is an autosomal recessive disease in most breeds of dogs (from Morgan's Handbook of Small Animal Practice). This means that it is inherited. I know of no link between previous bouts with parvovirus and PRA. The age of onset and exact mechanism of the disease varies a lot from breed to breed. Labs are reported to show onset of signs around four years of age usually.

Progressive retinal atrophy (PRA) results in the loss of rod cells first. These are cells responsible for night vision. Many dog owners think their dog has suddenly become afraid of the dark because they don't like to venture outside the light cast from a spotlight, porch light, etc. at night when the disease first shows up. Later, the cone cells are lost and daytime vision disappears, too. The whole process may take several years or may occur more quickly. Since cataracts are commonly associated with this problem it is a good idea to make sure the retinas are functioning prior to removal of cataracts, if there is any doubt. This can be done using electroretinography (ERG) even after the cataract is mature and the retina can not be examined visually. It is also possible to detect the degeneration before it is visible using the ERG technology.

In a surprising number of cases in which there is another companion animal (even a cat) in the household, changes in the relationship occur in which the blind pet becomes dependent on the sighted pet for guidance. My dogs used to run around the yard full speed together which fooled a lot of people into thinking Shasta couldn't possibly be blind.

There is one complication to leaving the cataract alone. Very late in her life Shasta developed problems due to displacement of the lens in one of her eyes. When there is a cataract the lens attachments weaken and the lens may migrate into the anterior chamber of the eye. This can lead to glaucoma and it is sometimes necessary to remove a lens even though it offers no hope of restoring vision. If the appearance of the cataract changes suddenly it is best to make an immediate trip to your vet or to the veterinary ophthalmologist.

I hope that your lab doesn't have this problem but if he does, I'm willing to bet that he will adjust to the blindness much better than you think he will and that he continues to be able to function pretty well.

Good luck with this.

Mike Richards, DVM

Last edited 01/31/05