TESTING FOR HEREDITARY EYE DISEASES IN SIBERIAN HUSKIES
Plus tests performed so far on our own dogs
(written April 27, 2008 by Katerina Paleckova)
Last year (August 2007), when I wrote a tribute to our beloved dog Kipp, who died due to glaucoma caused blindness, and suffered from pain, caused by this disease, I promissed to one day write a bit more about glaucoma, other hereditary eye diseases, the testing that can be performed, and mainly HOW we all can avoid the unnecessary suffering of our animals.
We just came back from another eye testing session, organized by Jämtland/Härjedalens Kennel Club in Östersund, in cooperation with certified veterinary eye specialist, Dr.Nils Wallin Hĺkanson.
This time I prepared some questions for Dr.Hĺkanson, in order to be able to share some basic information in form of the following notes. They generally concern gonioscopy.
Please note, that these notes were made not to criticise anyone, and also that they are not "perfect". They are my own notes as I put together the answers Dr.Hĺkanson generously gave me. None of them are quoting him either!
The term "narrow angles" in a result of a gonioscopy test, performed by certified opthalmologist, reffer to narrow (or underdeveloped) chamber angles in the eye. The degree of underdevelopment (goniodysgenesis) is often listed as either "mild", "moderate" or "severe". Some "severe" results may also include comment such as "changes occuring", which basically reffers to the start of changes in the eye, signalling development of glaucoma.
Generally goniodysgenesy is a defect, while glaucoma is a disease.
Narrow angles (not talking about severly narrow or with changes already occuring in the eye) are relatively common in the siberian husky breed and do not necesairly mean the threat of glaucoma occurance in the effected dog. The glaucoma may and may not develop in a dog with "moderate" degree, in a high age. The risk is relatively low.
However, breeders should be carefully screening the eyes of all their dogs they want to use in their breeding program, to have evidence, to be able to follow occurance history and to be able to eliminate the future occurance of narrow angles, and the risk of glaucoma development, by "breeding away" from the problem. By carefully selecting breeding pairs and monitoring their breeding program.
While you can go ahead and breed individuals with "mild" or "moderate" degree of so called "goniodysgenesis" (which in translation from the greek medical term meaning "underdevelopment, in our case we are talking about underdevelopment of the chamber angles in the eye), we should ALWAYS breed these individuals only to those with a clear result, which would be on the certificate stated as "without any comments" or "free of goniodysgenesis".
This way we are talking about "breeding away" from the problem.
Breeding "mild" to "mild" will produce "mild", breeding "moderate" to "moderate" will produce "moderate". Dogs with "severe" degree should not be bred, and in cases of absolute necessity ONLY to an individual with absolutly clear result.
Briefly: The degree of the chamber angles do not tell us if a dog has a glaucoma or if the disease will ever occur. They basically tell us how high or small the risk of the diesease's occurance in higher age is, as well as how much of a risk of this disease will the particular dog carry onto his/her offspring.
For example, if a dog in a mid age (6-8 years old) is gonioscoped with a "moderate" degree, the risk of him getting glaucoma is quite low, as generally the angles tend to get more narrow with age. That also makes it a bit dificult for an opthalmologist to determine if a glaucoma was hereditary or not, when diagnosing for example a 12 year old dog.
While for example our dear old Kipp (whom we decided to let go in age 14 due to blindness caused by progressing severe glaucoma) developed this disease in high age, and we will never find weather it was genetic or not, it is a good exmple of why one SHOULD do eye tests on as many dogs as possible. If Kipp's relatives and acestors were gonioscoped, we would have much more answers for not only his individual case, but for the future, when breeding on dogs, somehow related with him.
The tests we so far performed on our dogs, who come from many different lines, are just a beginning. In one way, we are fortunate that some of the lines we chose to work with have good feedback through monitoring the hereditary diseases (not just glaucoma, but also cataracts, PRA and other) and thus making it a lot more easier for us and our future breeding progam.
And now think, how much easier it would be for all breeders, if we all did our share in testing our dogs. The cost is quite small, comparing to the risks and the suffering of our beloved dogs.
Here in Sweden, the cost for a general eye test (which includes PRA, cataracts and cornea distrophy testing) is around 400,-SEK.
The gonioscopy test (for glaucoma) is the same price and it is permanent. That means that it is performed only once in the dog's life as the result is permanent.
That isn't so with the so called regular test, as that one must not be older than 1 year before breeding the dog. The results may change, as for example cataracts can develop later in the age. Generally, chosing to breed dogs after they reach certain age also helps to eliminate the problem as we may not be aware of a disease occurance when breeding the dog in a young age (for example 2 years old). That is why it is wise to use older, proven stud dogs, who already have a history of testing behind them, and most likely several offsprings, some of which had already been tested as well. The more information about the dog's background you are able to collect, the better. That's also why, if we have a male at home, it is wise to wait until a dog's offspring from the first litter are adult and tested (and here we are not talking necessairly just about eyes, but performance, temperament, etc.), before we decide to use him again. At least, this is one of our breeding philosophies in our kennel.
Here is a little statistics made from the eye tests performed on our dogs so far.
Since we learned about the importance of eye testing (2003) in siberian huskies, due to the relatively high risks of hereditary eye disease occurances, we eye checked 14 dogs so far. One was from our "A" litter, 2 from the "B" litter, 1 from "E" liter, and one is an offspring to one of the A litter dogs. Six of these dogs were used in breeding. From these fifteen dogs, 6 were also gonioscoped. NONE of the 15 had any comments on the regular eye test, 2 had a "mild" degree in the gonioscopy result, 1 "moderate" and 3 without any comments.
There isn't much conclussions to make from this, these dogs come from different bloodlines and not all were checked for the same diseases. But yet there is one quite cool thing - We are very happy and proud to announce, that our very own Sparky (Evening Spark Kipp d'Amundsen) is the historically very first Kipp d'Amundsen dog, that underwent both of these tests. And both with a clear result. What is even more important for us is that Sparky is out of our foundation male Buck (Buck of Geri's Den). Buck had been tested clear several times already, but today he went for his gonioscopy test together with his son Sparky, and was also tested clear! That is a great news for our kennel, as Buck is our true foundation dog, on whom we are building our line. He had already sired 3 litters for us, out of which Sparky is the oldest (4 years old now). This gives us a good background information for the future and we are very, very happy about being able to build on not just such talented, sweet dog with tremendous work ethic, good anatomy and excellent breed type, but now also complete proven eye genetic health. Dr.Hĺkanson commented on Buck's generally clear eyes and overall fitness and condition. He also thought both Buck and Sparky have lots of pigmentation in the eyes (a bit more dificult for peforming the test :), but very good for the "health").
As I said, we are basically at the beginning, but I would like to incurage all of you, the siberian husky breeders, to test your dogs as well. It is SO MUCH WORTH IT!
Here are some links you might find useful:
A current list of veterinary opthalmologists, certified for eye testing in Sweden: here
Common eye diseases in dogs: http://www.acvo.org/public/general.htm
American college of veterinary opthalmologists - official website: www.acvo.org
Hope this piece of information I gathered and experienced, can give you some feedback and can be of some practical use for you.
And last, but not least, please remember that eye testing (both, the regular test and gonioscopy) should be performed in siberian huskies on dogs intended for breeding, because SIBERIAN HUSKIES DO SUFFER FROM HEREDITARY EYE DISEASES.
It doesn't matter that some breed clubs do not list it as obligatory action - it is the breeders' responsibility!