More recent research has established two forms of this condition the more serious
of which is now referred to as:
Commonly referred to by its initials PRA, is a progressive inherited eye abnormality,
which causes eventual blindness. First discovered in Collies during the early 60s,
the Kennel Club were quick to extend its Eye Scheme to the Rough Collie, and despite
the fact that its mode of inheritance was not fully understood breeders concentrated
their efforts on eliminating the condition from their breeding stock, their vigilance
being responsible for its virtual eradication.
“A Window Into Their Soul” may sound a fanciful description for Rough Collies eyes;
they should however reflect their personality. Displaying their innate steadfastness
and gentle nature with its spark of mischief, together with a desire to please coupled
with personal initiative and high intelligence
Rough Collie enthusiasts have always emphasised the importance of eyes to breed type,
the 1898 Breed Standard describing them thus:
proving how little the ideal has varied in the intervening years.
Research, funded by three separate health research foundations interested in Choroidal
Hypoplasia[CH] plus the American Border Collie Association, has recently isolated
the mutation which causes CH in our own species and CEA in the wider collie family.
This in turn has allowed the development of a DNA test for the underlying condition,
and although more work is necessary before the two more sever forms, which can cause
sight deterioration, can be detected in this way it would appear to be the way forward.
Generalised Progressive Retinal Atrophy or GPRA is of early onset and typically apparent
by the time a puppy reaches six weeks of age. Current opinion is that this condition
does not affect Rough Collies in their country of origin, although it is known to
affect Collies in North America, which explains why the Collie Club of America’s
Health Foundation funded the research into its genetic inheritance which has since
established a DNA test for the condition. This has little relevance to breeders in
the United Kingdom or Europe unless they intend incorporating North American blood
lines into their breeding programme.
Central Progressive Retinal Atrophy or CPRA is in many ways a more insidious condition,
which can not be detected until it manifests itself sometime after the first year
of life, and frequently not until quite late in life explaining why breeders are
urged to submit their breeding stock for regular eye screening. The condition’s development
is also somewhat unpredictable often taking many years before serious loss of sight
is experienced if ever. It is also considered that improvements in canine nutrition
may have been largely responsible for today’s low incidence of the condition as it
is known that Vitamin E deficiency can affect the eventual outcome and most modern
feeds use Vitamin E as a preservative.
The possibility of a DNA test being discovered remains slim as the actual mode of
inheritance is still not fully understood, and with the number of confirmed cases
being less than 0•25% of all dogs tested under the BVA/KC Eye Scheme there is little
encouragement for further research.
Collie Eye Anomaly more usually referred to as CEA is a non-progressive congenital,
present at birth, hereditary abnormality of the eye which affects members of the
wider Collie family. Originally thought to be a simple recessive its mode of inheritance
no longer appears to be quite so simple and it is probable that its more severe expressions
involve additional gene mutations that have yet to be identified.
Usually bilateral, affecting both eyes, in its milder forms it is no more than a
slight lack of pigment to, or thinning of the optic disc which does not appear to
affect the sight in any way. In its more severe forms, which thankfully represent
less than 9% of the total Rough Collie population, it can manifest itself as Colobomas
of varying sizes and/or partially or wholly detached retina, this latter condition
Just as Collie breeders were beginning to congratulate themselves on a reduction
in the incidence of PRA, a new and far more far-reaching eye abnormality was diagnosed.
Initially discovered shortly after PRA was diagnosed in Rough Collies few were to
realise the seriousness or extent of this more wide spread condition for another
decade due to the concentration of veterinary and breeders efforts on one known to
caused eventual blindness.
Eye Test Certificates issued under the BVA/KC Eye Scheme have changed little during
the last thirty plus years — this one, dated 1990, was issued to a Collie who tested
clear for CEA and PRA but who had a small scar, due to an accident, on its left cornea,
and this fact is noted on the certificate
Being a congenital condition CEA can be detected at an early age, and as there are
no known genetically clear Rough Collies in this country, the only method of discovering
which if any puppies are clear or only mildly affected by CEA is to have the whole
litter eye screened for the condition, by a BVA listed ophthalmologist, at the age
of 6 to 7 weeks.