What They're Blind From

One of the many reasons we love our primary care vet, Dr. Brenda Culver, is because she has an intense interest in ophthalmology -- and when more than half of our animals are blind, that's really important!  Not only does Brenda have the ophthalmic diagnostic tools that the average vet doesn't have (like a slit-lamp and Tono-Pen), but she devotes a lot of her continuing education in veterinary medicine to ophthalmology.  So she regularly attends the annual gathering of the American College of Veterinary Ophthalmologists (ACVO) to learn about the latest research in this field.

At the ACVO conference in Boston a few weeks ago, Brenda saw on the seminar roster a presentation about a newly identified eye condition in standard Poodles.  She thought of our blind Poodle sisters, Molly and Priscilla, and figured she might learn more about what caused their blindness.

Brenda's initial diagnosis for them was progressive retinal atrophy, though she acknowledged at the time that we might always have a bit of a question mark about it.  Without knowing the history of the girls, when they started going blind, how old they were at the time, etc. -- and without being able to see the changes in their eyes as they occur -- you kind of end up making a diagnosis after the fact.  It can be like putting the pieces of a puzzle together in the dark, and sometimes there is no more complicated a puzzle than the very complex eye!

It turns out that the presentation in Boston explained a lot, and Brenda was excited to tell me last week what she learned.  It appears that Molly and Priscilla have a condition called early-onset photoreceptor dystrophy.

Essentially, it starts out as day blindness with reduced night vision, but then progresses to total blindness within one year of age.  The rods and the cones in the retina are initially affected differently, hence the day vs. night vision difference, but ultimately both rods and cones become nonfunctional, resulting in complete blindness.  (As I understand it, the rods are the photoreceptors that are very sensitive to light but not color, and thus are used for night vision.  Cones are the photoreceptors we use to detect color ... but they are not very sensitive to light, so only work well in daylight.  It takes both rods and cones working together to give us full vision.)

The researchers initially called it the “Sugar” syndrome because the first known example of this condition was in a brown standard Poodle named Sugar.  But now they have a formal name for it:  Early-Onset Photoreceptor Dystrophy.

And -- interesting point here -- some of the Poodles in the study were, yes, littermates.

There isn't anything we can do to restore Molly's and Priscilla's vision, but we always like learning as much as we can about these medical conditions in our animals.  Ultimately, of course, it would be great if there were a way to identify the underlying cause of this disease and be able to test for it before anyone breeds standard Poodles.  The researchers are now doing further research into the genetic basis of the disease.

I emailed one of the researchers today to let her know about Molly and Priscilla in case they wanted to include them in their on-going study.

Comments

[Shirley * James * Portland, OR]

Very interesting.

[Debbie Burke]

Your blog is not only entertaining and funny, but also a great educational resource. Thank you, Dr. Brenda, for digging deeper in eye problem for the two beautiful sisters. And as always, thank you, Steve and Alayne, for the fantastic life you provide for the wonderful critters, including go-ats!

[Maria Rose]

If the condition is identified early on are there any treatments?

[Suzanne]

They could not be more beautiful. They look so happy!

[Cindy]

Loved the signs on Margaret the goat! Would Molly and Priscilla be options for the Obama family? Keep up the wonderful work you are doing! You are an inspiration to all of us!

[Debbie]

A little knowledge can be a powerful tool. Thanks for my lesson today! Inasmuch as it is a dystrophy, I assume there is/was no pain involved for the girls?

[Colleen & Sweet Kitty Erin]

That is very interesting. I find it interesting it occurs in Standard Poodles. I wonder if it occurs in the Miniature or Toy poodle, as well, or only in the Standard because I have read before that PRA occurs in the 3 different sizes. I share your enthusiasm in the power of knowledge to help gain a better understanding of the animal's medical conditions. It's also good to know that research is being done to help future puppies. These two girls are certainly beauties. I love the picture of them.