Corneal Dystrophy is a progressive, inherited disease of the corneas, the clear tissue on the front of the eye. It causes oval or donut-shaped opacities in both eyes which progress, sometimes to blindness. Occasionally the condition remains static. The diseases is usually not painful but occasionally results in corneal ulcers which are. It comes in three forms:
- Epithelial, which affects cell formation
- Stromal, in which the cornea will become cloudy
- Endothelial which affects the cellular lining of the cornea
The disease is common in a number of breeds with different forms seen in different breeds, therefore there are likely several genetically distinct forms of the disease. While corneal dystrophy is sometimes reported in Australian Shepherds it is unusual and may actually be a non-hereditary issue
Corneal degeneration is a non-hereditary condition sometimes referred to as corneal dystrophy. If your Aussie is diagnosed with the latter you need to be sure what is really meant. In corneal degeneration either or both eyes develop lipid (cholesterol) or calcium deposits. These are a secondary effect of other diseases including uveitis, glaucoma, luxated lens, Cushing’s Syndrome, hypothyroidism, diabetes, or diets too high in fat. It may also be due to old age, particularly where there are other serious underlying health issues. If your dog has any of these other health issues or the corneal opacities are only in one eye, they may be secondary corneal degeneration rather than inherited dystrophy.
A final note, several of the diseases that can cause corneal degeneration are themselves inherited.