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Description or definition:
Corneal dystrophy is a
general term for an inherited dysfunction of the cornea. The
term encompasses a group of diseases of the cornea (the transparent covering
of the dogs eye) that are bilateral (present in both eyes),
non-inflammatory, and inherited. Some forms may be congenital (present
at birth), but more frequently they occur during adolescence and progress
gradually throughout life. Some forms are mild, while others can be
severe.
Symptoms:
Vary depending on the type of
corneal dystrophy. Corneal dystrophies all cause the cornea to become
opaque, but in different ways and with varying severity. Often corneal
dystrophies appear as gray-white, crystalline or metallic looking
areas in the center or cornea of the cornea. In general, corneal
dystrophies are usually not painful unless the condition leads to a
secondary break in the epithelial (outer) layer of the cornea.
However, in more severe cases some forms of corneal dystrophy can lead to
blindness.
 | Lattice-like dystrophy:
is seen as a cobweb of fine lines which develop into a lattice-like
pattern. This condition can develop in infancy, but is most
often seen during the reproductive peak of life. The condition
can range from very mild to severe.
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| Granular dystrophy: can
be seen as small white dots in the center of the cornea or may take
the form of lines radiating from the center of the cornea. This
condition usually starts while the pup is still young and the signs
can increase in size and number as the dog matures. By
adulthood, opacities are visible to the naked eye. Granular
dystrophies are usually very mild and often go unnoticed. Sight
may remain unaffected even late in life.
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| Macular dystrophy:
appears as a thin superficial corneal veil (haziness) with isolated
opaque areas when seen with a slit lamp. It is the least common
type of dystrophy. It usually starts during young adulthood.
Macular Dystrophy is a severe dystrophy which may cause considerable
damage by mid-life.
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| Crystalline corneal
opacities: produces a gray haze and/or needle-like crystals within
the cornea, spreading across its surface and, in some cases, obscuring
the vision of the dog. Although both eyes are affected, it may
not be necessarily at the same time or to the same degree.
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| Lipid corneal dystrophy:
is caused by fat deposits in the middle layer of the corneal cells.
The opaque areas can form a variety of patterns, and do not usually
cause any problems with vision and generally does not require
treatment. |
| Endothelial corneal
dystrophy: is a degeneration of the innermost layer of the corneal
cells. A build-up of fluid
in the cornea (corneal edema) clouds the normally transparent cornea and
may decrease vision. Early in the disease, there are not many
symptoms other than the opacity in the cornea. As the disease
progresses, the entire cornea becomes swollen and opaque. Pockets
of air can develop within the degenerated areas and cause corneal
ulcers. The corneal ulcers are treated with antibiotic ointment.
In severe cases, surgery, such as corneal transplants and corneal grafts
are possible.
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| Epithelial
corneal dystrophy:
is caused by a problem with the superficial layers of cells in the
cornea, and can (but does not always) result in corneal ulcers.
The ulcers are painful and as a result the dog will usually hold its eye
closed or blink often. The treatment can be as simple as some
antibiotic eye drops to treat the ulcer, or can require surgery to
remove the abnormal corneal cell layers. |
Diagnosis:
A veterinary ophthalmologist can
diagnose corneal dystrophy through a routine “slit lamp” examination.
These anomalies, if present, can also
be detected in a CERF exam. Because some forms of corneal dystrophy can
onset later in life, a normal CERF exam does not guarantee that the dog will
not later develop a hereditary eye problem.
Treatment:
No medication will “dissolve” the
opacity resulting from a corneal dystrophy. Surgical removal of the dystrophic
area may temporarily decrease the opacity in cases of epithelial dystrophy.
However, new opaque area will often reform once the cornea has healed.
Many of the corneal dystrophies are mild, non painful, and do not require
treatment. If corneal ulcers develop they are generally treated with
antibiotic ointment. Corneal transplants or corneal grafts may be
options for some dogs with more severe symptoms.
Links to sites about this disease:
This summary provided by:
| Jessica in Arizona |
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