Cataracts are any opacity of the lens and/or its capsule.
The cataract may be the size of a pinhead or involve the entire lens.
Of course, the size of the cataract determines the degree the dog's
sight is affected. Cataracts cause blindness by blocking the light from
entering the eye. Cataracts may be congental or acquired from an
injury or nutritional deficency, diabetes, retinal degeneration,
persistent pupilary membranes, etc.
Dogs with cataracts rarely need surgery, though it is possible.
Congenital cataracts may or may not be inherited.
Congenital eye disease is not always inherited.
Congenital diseases do not indicate
that a line of dogs is defective.
Primary cataracts are those present with no other eye disorder.
Secondary cataracts are those present with another disorder, such
as Progressive Retinal Atrophy (PRA).
There are two types of cataract genes, dominant and recessive.
Dominant cataracts appear when only one parent passes
along a gene for cataracts causing the offspring to be affected.
A dominant gene may have incomplete transmission of the gene - this means
that the disease may not show itself even though the offspring are affected, and
do carry and pass this defective gene to it's own offspring, but do not show
signs of the disease itself.
Recessive cataracts appear only when each parent passes along
a gene for cataracts. They can be autosomal recessives (both parents
must pass on a gene to their offspring) or polygenic.
Polygenic traits are those determined by more
than one set of genes, therefore, making it more difficult
to pinpoint the carriers in a breeding program.
The reason it is more difficult is that the traits may
or may not be expressed (seen).
Both dominant and recessive cataracts may occur
at the same time, making it more difficult to determine the
actual way the disease is transmitted.
Breeding Recommendations
Dogs that have cataracts should not be used for breeding
unless the dog has been diagnosised that the cataract is due
to trauma, nutritional deficencies, persistent pupillary membranes,
or some other metabolic or eye disease.
The cataract may be the size of a pinhead or involve the entire lens.
Of course, the size of the cataract determines the degree the dog's
sight is affected. Cataracts cause blindness by blocking the light from
entering the eye. Cataracts may be congental or acquired from an
injury or nutritional deficency, diabetes, retinal degeneration,
persistent pupilary membranes, etc.
Dogs with cataracts rarely need surgery, though it is possible.
Congenital cataracts may or may not be inherited.
Congenital eye disease is not always inherited.
Congenital diseases do not indicate
that a line of dogs is defective.
Primary cataracts are those present with no other eye disorder.
Secondary cataracts are those present with another disorder, such
as Progressive Retinal Atrophy (PRA).
There are two types of cataract genes, dominant and recessive.
Dominant cataracts appear when only one parent passes
along a gene for cataracts causing the offspring to be affected.
A dominant gene may have incomplete transmission of the gene - this means
that the disease may not show itself even though the offspring are affected, and
do carry and pass this defective gene to it's own offspring, but do not show
signs of the disease itself.
Recessive cataracts appear only when each parent passes along
a gene for cataracts. They can be autosomal recessives (both parents
must pass on a gene to their offspring) or polygenic.
Polygenic traits are those determined by more
than one set of genes, therefore, making it more difficult
to pinpoint the carriers in a breeding program.
The reason it is more difficult is that the traits may
or may not be expressed (seen).
Both dominant and recessive cataracts may occur
at the same time, making it more difficult to determine the
actual way the disease is transmitted.
Breeding Recommendations
Dogs that have cataracts should not be used for breeding
unless the dog has been diagnosised that the cataract is due
to trauma, nutritional deficencies, persistent pupillary membranes,
or some other metabolic or eye disease.
| Cataracts in Canines |
