Eye disease in dogs: a quick guide for buyers and breeders
A version of this article was first published on the BLIND DOGS ENABLED blog.
Like humans, all dogs have the potential to suffer from eye diseases, some of which can result in blindness. As with humans, some of these eye conditions are inherited, while others may be the result of trauma or ageing. For example, in Miniature Dachshunds, we know there is an inherited form of Progressive Retinal Atrophy (PRA) - cord1 - for which a DNA test exists and responsible breeders have been using this test to avoid producing affected puppies for more than 15 years. In our 2018 breed health survey (DachsLife 2018) around 2% of dogs were reported as having gone blind. The majority of these were dogs aged 9 or older, so these were likely to be a result of old age, rather than some inherited condition.
Eye diseases with DNA tests
There are 2 main ways in which breeders can ensure their dogs have healthy eyes and are suitable for breeding. Firstly, there are those conditions which are known to have a genetic origin and where a DNA test has been developed. These are, typically, simple recessive mutations and a number of different forms of PRA are of this type. Breeders can use a cheek swab test and identify whether their dogs are Clear (no copies of the mutation), Carriers (1 copy of the mutation) or Affected (2 copies of the mutation). Only “Affected” dogs are likely to suffer clinically with the condition being tested for.
As long as breeders only mate Carrier and Affected dogs to Clears, they will not produce Affected puppies. From a buyer’s perspective, knowing that at least one of your puppy’s parents is Clear, means you can be confident your puppy will not be clinically affected.
Clinical eye screening The second way for breeders to ensure their dogs have healthy eyes is to use the KC/BVA Eye Screening Scheme. This scheme has been going since the 1960s and includes not just an examination of the eye, but also of the eyelids and surrounding structures. It is sensible for any dog that will be bred from to have an eye examination before being bred from. This is a good way to ensure that any breed-related or inherited conditions can be identified at an early stage. Depending on what eye conditions are known to exist in a breed, it may be recommended for this eye examination to be repeated through a dog’s life. It is also good practice to carry out one of these examinations in older age to identify whether there may be any late-onset conditions that have occurred. The clinical eye screening programme is a bit like an MOT for a car; the results are applicable on the day of the examination and are no guarantee that something may not crop up in the weeks or months following the examination. The main purpose of the KC/BVA Eye Scheme is to ensure there is no clinical evidence of known hereditary eye diseases. Of course, this examination can also help to identify conditions where a genetic origin is not yet known. Some examples of eye diseases that might be identified by this screening include, Glaucoma, Retinal Dysplasia, Cataracts, Primary Lens Luxation and PRA. The examination might also identify conditions of the eyelid such as Distichiasis (extra eyelashes), Entropion (inward turning eyelids) and Ectropion (outward turning eyelids). In addition to some of these conditions resulting in blindness, some can be extremely painful and may require surgery.
Puppy buyers: do your research
If you are buying a Kennel Club registered pedigree puppy, you can find health screening results for your puppy’s parents by looking up their registered names in the Health Test Results Finder page. The KC lists both clinical screening results and DNA test results. The KC website is also a good starting point to find out what screening is recommended for each breed. Finally, if you’re a dog owner, your regular grooming session is a good opportunity to look out for any potential eye problems. At least weekly, make sure your pet’s eyes and eyelids aren’t red, that there’s no messy discharge from the corner of the eyes, and there are no signs of cloudiness or scratches. If your dog is scratching at its eyes or pawing its face, these might be other signs of an eye problem. If you’re at all worried, consult your vet who will be able to diagnose any problems and discuss the best treatment.
Read about Eye Disease as a priority in Dachshunds.