Corneal Dystrophy

This is an inherited condition when gray-white or silver crystalline opacities develop in or around the central area of the cornea. The opacities are almost always present in the same area of both eyes; they are symmetrical in appearance, and there is no accompanying inflammation or systemic illness. The preferred veterinary term for this condition is Crystalline Corneal Opacities (CCO). This term describes cone-shaped crystals that are produced in the cornea and that spread across the surface of the eye, potentially interfering with the dog's vision. No treatment is available, but thankfully the condition is not painful and usually not blinding, with a few exceptions.

Forms of Corneal Dystrophy

The corneal dystrophies are divided into:

• Epithelial and basement membrane which usually present as non-healing ulsers. These can be initiated by slight trauma to the epithelial surface of the eye;
• Stromal deposits of fatty material (lipids) commonly seen as an inherited condition in several breeds; these deposits often cause swelling of the cornea; Stromal dystrophies seldom lead to loss of vision, but vision loss has been observed in middle aged Airedale Terriers and aged Siberian Huskies. Treatment is usually unnecessary.
• Endothelial dystrophy is associated with progressive corneal swelling, which can lead to corneal ulcers. Treatment of dystrophies with progressive corneal edema is not usually necessary.

Dystrophies Differ from Corneal Degenerations

Dystrophies differ from corneal degenerations because they usually affect both eyes as in bilateral cataracts (though not simultaneously or to the same degree in every incidence), appear in certain breeds, do not have inflammation, often affect the stroma (connective and supportive tissue) and rarely cause blindness.

A pet owner usually observes a corneal opacity in the central area of the eye, with no evidence of pain. The opacities appear as gray or white crystalline

If the dystrophy affects the deepest layer of the cornea, as it does in Boston Terriers, Chihuahuas and Dachshunds, it can lead to swelling and blindness. Most dystrophies are more superficial, such as those seen in Siberian Huskies, Beagles and King Charles Spaniels. Affected dogs should not be bread in order to avoid perpetuating the affect.

Dog breeds that are predisposed to corneal dystrophy

References:
1. Corneal dystrophy in the dog and cat. Cooley PL, Dice PF 2nd.

Canine Eye Diseases and Vision Disorders