Retinal pigment epithelial dystrophy (RPED) in dogs

There are many forms of progressive retinal atrophy in dogs, one of which is a rare type called retinal pigment epithelial dystrophy (RPED). It is a hereditary disorder that's known to be an autosomal recessive genetic defect which ultimately leads to a dog's vision being impaired. The condition is degenerative that typically affects both eyes and fortunately, it is less commonly seen that progressive retinal atrophy (PRA) and it usually affects an older dog where the pigment cells found at the centre of a retina are negatively impacted. It is worth noting that the condition is also occasionally referred to as central progressive retinal atrophy.

Symptoms to watch out for

A dog suffering from the condition has trouble seeing anything that is stationery, especially when they find themselves in brighter natural or artificial light. The reason being that the best part of their vision which is the centre of the retina, are so negatively impacted it seriously impacts their ability to focus on anything that’s not moving. With this said, affected dogs can still see any moving objects thanks to the fact their periphery vision is not impaired by RPED. With this said, as the condition progresses, a dog's ability to see does get gradually worse, but rarely does the disorder cause a dog to totally lose their vision and go blind. However, working dogs suffering from the condition find it extremely hard to work in any sort of bright light.

Diagnosing the condition

A vet would want to have a dog's full medical history before carrying out a thorough examination of their eyes when they are suspected of suffering from the condition. The vet would want to eliminate any other causes which includes a dog suffering from a chronic deficiency of Vitamin E. The vet would refer a dog to an ophthalmologist who would be in a better position to establish a definitive diagnosis. They would also be able to recommend the best way forward both for a dog and the owner.

Tests can be carried out through the Canine Eye Registry Foundation (CERF) which also helps establish whether a dog is suffering from retinal pigment epithelial dystrophy. Dogs can also be DNS tested to see if they carry the gene responsible for the disorder.

Breeds most at risk

Some dog breeds are more at risk of inheriting and developing the condition than others and this includes most types of Collies. They are typically diagnosed as suffering from the disorder when they are 18 months old or older. Other breeds that appear to be predisposed to the condition include the following:

• Briard
• Rough Collie
• Smooth Collie
• Golden Retriever
• Labrador Retriever
• Shetland Sheepdog
• Cocker Spaniel
• English Springer Spaniel
• Cardigan Welsh Corgi

Treatment options

Unfortunately, there are currently no treatment options for the condition, but any breed predisposed to suffering from the condition should be eye tested before being used in a breeding programme. This is the only way of reducing the risks of their offspring inheriting the condition. Dogs known to suffer from the condition should be spayed or neutered to prevent any accidental matings. A vet might recommend giving a dog affected by retinal pigment epithelial dystrophy Vitamin E which can be supplemented to their diet, although the effects of doing this remains questionable as to how much it helps.

Prognosis

Dogs affected by the condition don't typically go completely blind although their vision is impaired. With this said, they still retain their peripheral vision even when suffering from RPED and therefore go on to lead full lives. However, any dog known to suffer from the condition, as previously mentioned should be spayed or neutered to prevent accidental matings and should not be used for breeding purposes.