What is retinal dysplasia?    Retinal dysplasia

The normal retina lines the back of the eye.  The retinal cells receive light stimuli from the external environment and transmit the information to the brain where it is interpreted to become vision. In retinal dysplasia, there is abnormal development of the retina, present at birth. The disorder can be inherited, or it can be acquired as a result of a viral infection or some other event before the pups were born.

There are 3 forms of retinal dysplasia

i) folding of 1 or more area(s) of the retina. This is the mildest form, and the significance to the dog's vision is unknown.

ii) geographic - areas of thinning, folding and disorganization of the retina.

iii) detached -  severe disorganization associated with separation (detachment) of the retina.

The geographic and detached forms cause some degree of visual impairment, or blindness.

How is retinal dysplasia inherited?

In many breeds, inheritance has been shown or is suspected to be autosomal recessive. In others, the mode of inheritance has not been determined.

What breeds are affected by retinal dysplasia?

Breeds most commonly affected with the detached or geographic form of this condition include the American cocker spaniel, Bedlington terrier, English springer spaniel, golden retriever, Labrador retriever, Sealyham terrier, and Yorkshire terrier.

Retinal dysplasia has been seen in many other breeds as well, including the akita (folds,geographic/detachment), Australian shepherd (folds), beagle (folds), Belgian malinois (folds), border terrier (folds), bull mastiff (folds), Cairn terrier (multifocal folds, geographic), cavalier King Charles spaniel (folds and geographic/detached), clumber spaniel (folds), collie (folds), field spaniel (folds), German shepherd (folds), Gordon setter (folds), mastiff (folds), Norwegian elkhound (folds), old English sheepdog (folds), Pembroke Welsh corgi (folds and geographic/detached), rottweiler (folds), samoyed (folds,geographic/detached), soft-coated wheaten terrier (folds), Sussex spaniel (folds).

Labrador retrievers and samoyeds with retinal dysplasia may also have a bony abnormality called chondrodysplasia, or dwarfism. The dog's front legs are shorter and thicker than normal.

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What does retinal dysplasia mean to your dog & you?

The effect on vision of the mildest form (folding of the retina) is not known. The abnormal retinal folds may disappear with age in dogs that are only mildly affected.

There is some loss of vision or blindness with the geographic or detached forms of retinal dysplasia, and this is present for the dog's whole life. With their acute senses of smell and hearing, dogs can compensate very well for visual difficulties, particularly in familiar surroundings. In fact owners may be unaware of the extent of vision loss. You can help your visually impaired dog by developing regular routes for exercise, maintaining your dog's surroundings as constant as possible, introducing any necessary changes gradually, and being patient with your dog.

How is retinal dysplasia diagnosed?

The condition is present from birth. At 3 to 4 weeks of age, the breeder may notice that severely affected pups are less active and frequently bump into objects.  A veterinarian will be best able to examine the pup's eyes for this condition with an ophthalmoscope at 12 to 16 weeks of age, when the retina is mature.

In less severely affected pups, or those with retinal folds only, no behavioural abnormalities are likely to be seen.  Your veterinarian may find this condition during an eye exam and/or  you may begin to suspect there is a problem with your dog's sight.

For the veterinarin:

Ophthalmic exam - There may be a searching nystagmus due to the lack of normal development of neural visual pathways. PLR may be absent. The anterior segment is clinically normal.  You may see multiple gray or white spots or streaks (multifocal retinal folds) or retinal detachment, with or without intraocular haemorrhage. The retina often remains attached at the optic disk. Inherited retinal dysplasia can not be distinguished by ophthalmic exam from the acquired form.

How is retinal dysplasia treated?

There is no treatment for retinal dysplasia. With their acute senses of smell and hearing, dogs can compensate very well for visual difficulties, particularly in familiar surroundings. In fact owners may be unaware of the extent of vision loss. You can help your visually impaired dog by developing regular routes for exercise, maintaining your dog's surroundings as constant as possible, introducing any necessary changes gradually, and being patient with your dog.

Breeding advice

Dogs affected with geographic or detached retinal dysplasia, their parents and their littermates should not be bred. The situation is less clear in those breeds that have retinal folds, since the genetic relationship between the 3 forms is not known.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources

Ackerman, L. 1999. The Genetic Connection. p. 168-171.  AAHA Press. Lakewood, Colorado. This reference contains a comprehensive list of breeds with whom this disease has been associated.

Copyright 1998 Canine Inherited Disorders Database. All rights reserved.
Revised: September 20, 2004.

This database is funded jointly by the Animal Welfare Unit at the Atlantic Veterinary College, University of Prince Edward Island, and the Canadian Veterinary Medical Association.