Issue Description It is the development of gray-white opaque
deposits of calcium and fats under the surface of both of the dog's
Causes Corneal Dystrophy is an inherited abnormality
that affects one or more layers of the cornea. Both eyes are usually
affected, although not necessarily symmetrically. Chronic or recurring
shallow ulcers may result, depending on the corneal layers affected.
Affected Breeds Several breeds can be affected by this disorder
including: The Airedale, Afghan Hound, American Cocker Spaniel,
Basenji, Beagle, Bearded Collie, Bichon Frisé, Boston Terrier, Boxer,
Briard, Cavalier King Charles Spaniel, Chihuahua, Chow Chow,
Dachshund, English Springer Spaniel, German Shepherd Dog, Golden
Retriever, Irish Wolfhound, Labrador Retriever, Miniature Pinscher,
Nova Scotia Duck Tolling Retriever, Pembroke Welsh Corgi, Rough
Collie, Samoyed, Shetland Sheepdog, Siberian Husky, and Vizsla.
Symptoms Confusion often arises over the use of the term
"corneal dystrophy" in dogs. Technically, "corneal dystrophies" are
diseases of the cornea that are bilateral, non-inflammatory and
inherited. The confusion arises because the term "corneal dystrophy"
is sometimes used to refer to a disease with similar clinical signs
but is not hereditary. A more appropriate term for the non-inherited
conditions is corneal degeneration. In most breeds, corneal dystrophy
appears as gray-white, crystalline or metallic opacities in the center
of the cornea or close to the periphery. These opacities may affect
any layer of the cornea, the epithelium (outer layer), the stroma (the
thick, middle layer), or the endothelium (the inner layer). The
opacities are usually oval or round and are sometimes doughnut-shaped.
The age of onset of the disease varies within and among dog breeds and
may range from 4 months in Airedale Terriers, to up to 13 years in
Chihuahuas. The opacities usually progress but in some cases they
remain static. Their progression may be very slow and may or may not
lead to blindness (common in Cocker Spaniels, Poodles, Samoyeds,
Siberian Huskies, Pointers, German Shepherds, and Bichon Frises). On
the other hand, progression may be rapid and lead to blindness (more
common in Airdale Terriers, Boston Terriers, Chihuahuas and
Dachshunds). The mode of inheritance varies among breeds and in many
breeds it is unknown. In the Airedale Terrier it is thought to be a
sex-linked trait and in the Siberian Husky, Corneal Dystrophy has been
shown to be a recessively inherited trait with variable expression.
Corneal dystrophies are usually not painful. In a few breeds, however,
a dystrophy can lead to secondary breaks in the epithelial (outer)
layer of the cornea. When this occurs a painful corneal ulcer develops
requiring intense treatment. In other breeds, a painful ulcer may not
develop and the dystrophy itself is not treatable. No medication will
"dissolve" the opacity. Surgical removal of the dystrophic area may
temporarily decrease the opacity in cases of epithelial dystrophy.
Often, however the opacities will reform in the healed cornea.
Diagnosis You or your veterinarian may notice one or
several small white to gray areas in one or both of your dog's eyes.
Magnification may reveal crystalline deposits within the deeper layers
of the cornea or simply a haze.
If there are epithelial
erosions, your dog may show signs of discomfort such as increased
tearing, squinting and rubbing the eye. Your veterinarian will examine
the eye for erosions or, in the case of edema, for bullous
keratopathy. A fluoroscein dye test is used to check for corneal
Treatment For dogs that experience painful, shallow
epithelial erosions (primarily Boxers and Shetland Sheepdogs),
treatment is aimed at eliminating the lesions. This will involve
medication in the eye. Surgical treatment may be required if chronic
Most stromal dystrophies cause no
discomfort and do not interfere with vision. No treatment is
In endothelial dystrophy, no treatment is
necessary in the early stages of the disease. As the edema (or fluid
build-up) in the cornea increases, dogs may develop "water blisters"
(bullous keratopathy) which can rupture and cause painful erosions.
Your veterinarian will prescribe eye medication appropriate for
bullous keratopathy (hyperosmotic solutions) as well as treatment for
ulcers if present. There are surgical treatments which can be
performed by a veterinary ophthalmologist if the erosions persist or
recur frequently despite medical therapy.