When examining for PRA there also will be found a lot of other
eye diseases and faults. There are different forms of CATARACTS.
In its smaller forms cataracts make a very little affect on the
dogs sight. A TOTAL cataract also means total blindness and comes
often as a result of PRA. This can often be seen when a dog is tested
at 7-8 years of age. You can not see through the lens into the retina.
An ERG test is the only way to see if there is any PRA.
All cases of confirmed PRA approved for publishing
can be found here.
It is impossible
to point out a specific dog as the only cause to this disease. In the
pedigrees of these dogs one can find dogs from both England and USA
as carriers of the disease. The foundation stock in USA consists of
8 dogs and in UK of 5 dogs. These early imports have been inbred very
hard from the beginning and in some lines this hard inbreeding has
continued for 10 - 12 generations.
ILAC was started in order to find out the occurrence of PRA in
Lhasa Apso around the world. To increase the knowledge of this
disease in the breed it is necessary to test as many Lhasa Apsos as
possible and to start with the old ones already used in the breeding.
To be sure and safe it is also necessary to test the parents of
every planned litter. The ophtalmologic veterinarians are talking
of an onset age from 2 years up to 8 years and nobody can say a dog
is clear at the age of five years. It is impossible to say if a dog
is a carrier or a non-carrier. The only known carriers are the parents
of a PRA dog and its puppies and the PRA dog itself. What some people
call a non carrier from a “free" line can later on be a known carrier
as well as developing PRA itself.
Samples of genes from affected Lhasa Apsos have been compared to
genes from Irish Setters. Unfortunately the Lhasa type of PRA is not
the same as the Setter type. Lhasa Apso breeders can be happy if they
can use a proper DNA test before the year 2000.