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RETINAL
DYSPLASIA Note for Pet Owners:
This information is provided by
Provet for educational purposes only.
You should seek the advice of
your veterinarian if your pet is ill as only he or she can correctly advise
on the diagnosis and recommend the treatment that is most appropriate for
your pet.
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Description
In domesticated mammals the retina is the reflective area
at the back of the eye which responds to light . The retina contains special
light-sensitive cells called rods and cones that help an individual to
recognise the presence of light and form an image of its environment - as
white and shades of grey (rods) or colours (cones). Retinal dysplasia is a
congenital (present at birth) disorder in which the retina does not develop
properly.
Cause
Retinal dysplasia is a
congenital (present at birth) disorder in which the retina does not develop
properly and there are two main types :
- An inherited disorder genetically transmitted from the parents
- Due to a single autosomal recessive gene
- An acquired (non-inherited) disorder - due to a variety of causes
including :
Breed Occurrence
In the UK Eye Screening and Certification
programmes for breeders and owners exist for the following breeds of dog ;
- Multifocal Retinal Dysplasia -
American Cocker Spaniel, Cavalier King Charles Spaniel, English Springer
Spaniel, Golden Retriever, Hungarian Puli, Rottweiler
- Total Retinal Dysplasia - Bedlington
Terrier, Labrador Retriever, Sealyham Terrier
A BVA Canine Health Scheme Brochure on
"Hereditary Eye Disease in Dogs" is available- If you would like to receive a
free copy of this publication please contact us with your postal delivery
address at the following email address info@provet.co.uk
Signs
Affected puppies may not have any signs of a visual defect, or they may
have poor eyesight (multifocal retinal dysplasia) or be totally blind (total
retinal dysplasia) from birth
Complications
Total retinal dysplasia is often complicated by the presence of other eye
disorders including microphthalmos or nystagmus- especially in Sealyhams
In one form of retinal dysplasia seen in Labrador Retrievers the eye
problem is associated with skeletal abnormalities as well. This form, which is
due to a single autosomal recessive gene for the skeletal disease has
incomplete dominance over the eye, has not been reported to occur in the
UK.
Diagnosis
Diagnosis is confirmed by examination of the retina with an ophthalmoscope which
may reveal the presence of :
- Patchy abnormal discolourations
- Folds in the retina
- Ridges in the retina
- Rosettes
- Detachment of the retina - focal or complete
These changes may not be obvious until the puppy is 6 months of age.
Two forms of the disease are recognised in dogs :
- Multifocal Retinal Dysplasia
- Folds of the retina - appear like grey streaks
- Rosettes of abnormal colouration on the retina - appear like grey
patches
- Increased reflectivity of the tapetal (coloured area) of the retina.
Total Retinal Dysplasia
- Non-attachment or complete detachment of the retina
-
Intraocular haemorrhage may be present
- Leukocoria - white appearance (like a cataract) due to the detached
retina appearing behind the lens
- Microphthalmos (a small eye) may be present - especially in Sealyhams
- Nystagmus (uncontrolled rhythmic movements of the eye) may be present -
especially in Sealyhams
Treatment
There is no treatment for the damage to the retina that occurs with Retinal
Dysplasia and the main focus is to try to identify clinically affected dogs and
apparently normal carriers of the disease and avoid breeding from them. Exposure
to non-genetic causes of retinal dysplasia , such as canine herpesvirus
infection, should be avoided in pregnant bitches
Prognosis
Individual animals with mild forms of the disorder can live normal lives, but
totally blind puppies present problems for owners.
Updated October 2013
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