Retinal dysplasia in dogs

Retinal dysplasia in dogs is a condition of the eye, which causes round clumps, sometimes known as “rosettes” or “folds” to form in the retinal tissue. Retinal dysplasia can be caused by a wide variety of factors, but is usually genetically inherited, with various different popular dog breeds being particularly prone to the condition. Retinal dysplasia can affect the vision of the dog in question, but is not painful and is not progressive.

Read on to learn more about retinal dysplasia in dogs, plus find out what breeds and types of dogs are most at risk of developing the condition.

What causes retinal dysplasia in dogs?

The retina of the eye is composed of two layers, which should form and develop together. Retinal dysplasia occurs when the two layers do not develop properly, causing folds or creases to form between them.

Retinal dysplasia is usually genetically inherited through the breed line and some breeds of dogs in particular are more prone to developing the condition than others (more on this later).

Retinal dysplasia can also be caused by a variety of other means, including vitamin deficiencies, damage to the eye itself, and viral infections that affect the eye. If a bitch is affected by the canine herpes virus during pregnancy, the virus can affect the puppies prior to delivery and potentially cause retinal dysplasia to occur.

The three types of retinal dysplasia in dogs

There are three different basic types of retinal dysplasia in dogs, which are classed according to their effect on the eye and how they have formed.

• Focal or multi-focal retinal dysplasia refers to small folds within the retinal tissue, either singularly or multiply. These may become less pronounced as the dog approaches maturity, but may cause blind spots in the dog’s vision.
• Geographic retinal dysplasia lesions appear to be horseshoe-shaped or irregularly shaped, and may be present either instead of or alongside of folds in the retinal tissue. While focal or multi-focal folds may lessen or disappear as the dog ages, geographic retinal lesions will not. This type of retinal dysplasia results in visual impairment and possible blindness.
• The most severe form of the condition is complete retinal dysplasia accompanied with detachment, which causes blindness and may potentially be accompanied by a range of secondary eye problems such as cataract or glaucoma.

Breeds most at risk of inheriting retinal dysplasia

Retinal dysplasia in the dog is most usually a hereditary, genetically inherited condition, with some breeds much more prone to presenting with the disorder than others. Breeds within the UK that are most at risk of developing the condition plus the type of the condition that they usually present with are:

• Sealyham Terrier: Complete retinal dysplasia
• Bedlington Terrier: Complete retinal dysplasia
• Beagle: Focal or multi-focal retinal dysplasia
• Rottweiler: Focal or multi-focal retinal dysplasia
• Springer Spaniel: Prone to both focal or multi-focal, and geographic retinal dysplasia
• Cocker Spaniel: Focal or multi-focal retinal dysplasia
• Cavalier King Charles Spaniel: Either geographic retinal dysplasia, complete retinal detachment, or focal/multi-focal folds
• Labrador Retriever: Any of focal or multi-focal, geographic, or complete retinal detachment may be seen in this breed. Complete retinal detachment in the Labrador Retriever is sometimes associated with a congenital defect of the skeletal system.
• Samoyed: Complete retinal dysplasia, again sometimes associated with skeletal defects
• Yorkshire Terrier: focal or multi-focal retinal dysplasia

Identifying retinal dysplasia in dogs

With a condition that causes folds or other flaws within the eye, you might reasonably expect that the condition is visible and easy to identify by observation; however, this is not the case. It is not possible to observe the flaws or physical signs of the condition by looking with the naked eye, and so often for dog owners, the first indications that something is amiss is a simple concern that the dog’s vision might not be 100%, for instance if the dog appears particularly clumsy or prone to bumping into things.

In order to definitively identify the condition and rule out any alternative reasons for this behaviour, examination using an otoscope, or even a more complex examination by a specialist veterinary ophthalmologist will be required.

In breeds where the condition is thought to be linked to or associated with a skeletal defect (such as is the case with the Samoyed and the Labrador Retriever) DNA testing can be used to identify the genetic defect that leads to the condition.

Treating and managing the condition

Currently there is no way of reversing of treating retinal dysplasia in dogs, and a dog that has been identified to have the condition will have it for life. Dogs that have any form of retinal dysplasia, however mild, should not be used for breeding, as the condition is hereditary.

Depending on how severe the condition is, the associated vision loss that goes with it may be totally manageable, and many pet dogs with retinal dysplasia live full and healthy lives with very little difficulty caused by the condition.

Retinal dysplasia is not progressive, so once the condition is identified it will not worsen over time, although dogs, much like people, may suffer from additional eye problems or failing eyesight as a natural side effect of aging in later life.