not sure you see.

Hi Frank.

A friend pointed your post out to me. As you probably know, I no longer post on the board but thought I would PM you an answer. Unfortunately the answer to your question is not a simple yes or no.

In the BVA/KC/ISDS eye testing scheme there are two lists. One is the list of breeds known to have a problem with an eye condition and the other list is for breeds where a problem has been found but that at that date it is not know whether the breed has a problem or whether the particular dog is a "One off" situation. As an example, I know one Dalmatian with a problem and two GSP's. So few that neither breeds are on either list! We have found several Nova Scotia Duck Toller's with a PRA problem and so this year they are on the "Under Investigation" list.

In the case of Bullmastiffs, a number have been found to have a condition called "Persistent Pupillary Membrane" and as such they have gone on the Under Investigation list for this condition.

PPM is not a simple proposition and mode of inheritance is at the moment not known. The only breed with a big problem is Basenji's where over 50% of examined dogs are positive! (I do in fact know of one Rough Collie which also is alleged to have PPM although I am not convinced it is a correct diagnosis!)

During the last three weeks of fetal development the Pupillary Membrane undergoes a degeneration and is usually completely gone by six weeks of age. But in some cases it takes considerably longer and in a few cases never really clears. Often all that is left is a single strand of membrane although in some cases it appears almost as a cobweb across the eye, invisible to the naked eye. In all but the very worst cases the dog is unlikely to ever have a sight problem. Apart from Bullmastiff's, it is also under investigation in Miniature Wire Haired Dachshund's, Lancashire Heelers, Petit Basset Griffon Vendeen, Sibes, Cockers and Westies.

One of the (To me anyway) bad points of the eye testing scheme is that the ophthalmologist is only allowed to "Fail" dogs for conditions on the full list. He cannot fail them for conditions under investigation so checking the Breed Record Supplement will not give any guide to carriers in cases like this!

So, do you test or not? A reason for not testing is that the dog is unlikely to suffer any ill effects. The down side of this is that if the condition is ignored and gets to be prevalent in the breed then a large number of dogs are going to suffer from slight visual impairment. For what it's worth, I would test, and the reason I say that is because if the will is there then the condition should be able to be eliminated from the breed before it gets too much of a hold. Bullmastiff's are not a numerically large breed so the available gene pool is small. Obviously small gene pools are so much easier to swamp with a mutant gene than a larger gene pool so to me it's imperative to bite the bullet as soon as possible in the case of ANY hereditary ailments affecting numerically small breeds.

Regards, John   

Thanks John for your answer, how much do the eye tests cost? Also how come you dont post on this site no more you are  a great source of information.

Thanks for your help Frank.