Hereditary Defects Advice - Glaucoma in Border Collies

There are two types of glaucoma – primary and secondary. The causes are different, but they manifest themselves in the same way – namely a build-up of the fluid within the eye, which increases pressure, causing pain and which if untreated, can cause blindness and ultimately may require the removal of the eye.

Of particular concern in Border Collies at the moment is primary glaucoma (or - more specifically - narrow angled glaucoma) - the predisposition to which is known as goniodysgenesis. Dogs diagnosed as being Affected by goniodysgenesis have abnormal fluid drainage channels, which may result in inadequate drainage from the eye. If a dog is diagnosed as being Affected with goniodysgenesis, it does not necessarily follow that they will develop glaucoma. Also, a dog that has been classified as Unaffected by goniodysgenesis cannot be presumed to be genetically Clear. It is not known exactly how this condition is inherited – it could be that many genes that are responsible (polygenic), which makes it difficult to formulate a genetic test. There do seem to be strong indications that the inheritance follows specific breed lines, therefore the BVA recommend, in order to minimise the incidence of goniodysgenesis, breeding from Affected dogs should be avoided.

The test for goniodysgenesis is called a gonioscopy, and it can only be carried out by certain eye panel vets. It is a completely different test to the eye exam - the two tests can be done at the same visit, but it is important the gonioscopy is carried out before the eye drops are put in. The eye vet will use a lens which must be placed directly on the eye. Some dogs find this uncomfortable and may find it difficult to stay still for long enough to carry out the test. It is for this reason that vets often request that dogs are at least 6 months of age before they go for a gonioscopy.

In 2011, the gonioscopy costs £40.00 per dog and there is no discount for testing more than one at a time. It is important to note that at present, the BVA has not scheduled Border Collies as being ‘at risk’ of goniodysgenesis, so the results of the test are not officially recognised by the KC or BVA in any of their testing schemes. The BVA eye panel has carried out a study to help them establish a Normal (Unaffected) baseline for Border Collie eyes from which they can standardise the results, paving the way for an official Scheme and future genetic testing. In the meantime, an independent database has been set up where gonioscopy test results can be submitted for inclusion, and test results from round the world may be viewed. Submission of test results here is entirely voluntary on the part of the owner, so this database is not necessarily exhaustive.