Retinal dysplasia

What is ... ?: 

 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 ... 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 does ... 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 ... 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.

How is ... 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.

For the veterinarian: 

 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.

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.


What breeds are affected by ... ?
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