The November 2017 edition of the Kennel Gazette has an excellent article on eye disease in dogs by the well-known ophthalmologist, Dr Peter Bedford. He asks the question "is it necessary to continue with routine clinical eye examinations or has DNA testing rendered them obsolete?".
In Dachshunds, we have had the DNA test for Cord1 PRA since about 2005 when it was developed to address early-onset blindness in Mini Longs. It was subsequently made a requirement under the Assured Breeder Scheme for Mini Smooths (2008) and Mini Wires (2011). We now know there is a second mutation associated with the age of onset of this form of PRA but, as yet, there is no DNA test. We also have a DNA test for Norwegian Day Blindness (NPHP4) which is present with a low mutation frequency in Wires and Mini Wires.
Peter Bedford says, in his article, "...it remains essential that (clinical) screening continues, to maintain the effective control for ocular disease...". There are over 30 inherited eye diseases affecting 59 different breeds, of which gPRA is listed in the BVA/KC/ISDS Eye Scheme for Mini Long Dachshunds.
The Eye Scheme also lists diseases which have been noted in breeds (Schedule B) and which may be inherited, although this has not been proven. The conditions listed for Dachshunds are:
We also know from our Breed Health Surveys that Distichiasis (an extra row of eyelashes) has a very high prevalence in Mini Longs (13% of a Breed Council sample had a clinical concern and 80% of dogs were affected). This is a painful condition that can easily be detected by a clinical eye examination.
Routine screening will pick up any emerging conditions and can also be useful for confirming or disproving concerns that may be being discussed anecdotally. We know there are cases of Dachshunds going blind and these are not due to Cord1 PRA, and we get occasional reports of Sudden Acquired Retinal Degeneration Syndrome (SARDS). Many reports of Dachshunds going blind are simply what would be expected in old dogs, so we shouldn't assume there is necessarily a problem in the breed.
Good practice would be to screen clinically at 12-18 months (before breeding) and then again over the age of 7 to check for any late-onset conditions.
Peter Bedford's (unsurprising) conclusion: Yes, it is necessary and important for breeders to use clinical eye examinations in parallel with any recommended DNA tests.
Read more about our recommendations on screening for Eye Disease.
Read our Eye Disease Fact Sheets: