Dystrophy is the degeneration of tissues due to disease or malnutrition, frequently inherited.  As with all diseases of the eye, corneal dystrophies are variable in cause and severity making their treatment very specific to your pet’s condition.

Superficial Corneal Dystrophy is characterized by white, opaque mineral/lipid (cholesterol and/or calcium) deposits with the cornea (the clear front part of the eye).  The size, shape and density of the plaque like material are quite variable and can result in painful inflammation (keratitis) and secondary ulceration.  This may require surgery to correct in the more severe cases. Although these affected areas can be highly visible, they rarely cause blindness.

Treatment. Our goal in treating superficial corneal dystrophy and corneal degeneration with topical medication is to improve the health of normal cells overlying the corneal surface.

In cases of severe progression and discomfort we can remove much of the mineral deposits through superficial keratectomy, a surgery in which the outer layer of the cornea and the mineral is removed.  If a deep ulcer is found as a result of the degeneration, a grafting (conjunctival flap) procedure may be necessary to allow the cornea to heal.

Corneal Endothelial Cell Dystrophy/Degeneration The cornea is normally the transparent “windshield” of the eye, serving to protect the internal structures of the eye while allowing light to enter the eye.  The endothelium is a single layer of cells that lines the inside of the cornea.  Though only a single cell layer thick, this layer is vital in maintaining a clear cornea and functional vision.  The cornea normally maintains its clarity through a number of factors, including a very regular arrangement of supportive stromal fibers in a relatively dehydrated state compared to other body tissues.  If water is allowed to build up, the corneal fiber arrangement will be disrupted and the clarity of cornea will be reduced.

Endothelial cells are very slow and incomplete in their regeneration.  Therefore, if cells are lost, the remaining cells attempt to spread out to take the place of the lost cells.  As long as the number of functional endothelial cells remains above a critical threshold number, they will be able to prevent a gap in this lining and successfully keep the cornea clear.  If the number of cells falls below this threshold they will no longer be able to keep the entire cornea dehydrated and clear.  The result is a progressive blue cloudiness that develops across the cornea (corneal edema).

This situation can develop due to an inherited condition in certain breeds, such as Dachshunds, Chihuahuas and Boston Terriers.  In this inherited condition it is referred to as endothelial cell dystrophy.

Endothelial degeneration also occurs following death or damage to the endothelial cells as a secondary disease to many intraocular disorders.  These can include uveitis, elevated intraocular pressure (glaucoma), and endothelialitis. Endothelialitis is often thought to be an immune mediated process.

Fluid accumulation within the cornea is not a painful condition by itself; however, this fluid can sometimes cause the formation of small blisters in the cornea called bullae.  If these bullae reach the surface of the cornea and rupture, they will leave a painful corneal ulcer.  These ulcers can heal quickly with appropriate medications but if they become a recurrent problem, we may recommend a surgical procedure to help minimize bullae formation and heal the erosion.

Treatment for Corneal Endothelial Cell Dystrophy/Degeneration. This condition can be stabilized and in some cases partially or slightly reversed with proper medial therapy.  Eye medications that can help treat endothelial cell disease include topical corticosteroids (judiciously), NSAID’’s, immunosuppressive drops and antibiotic drops, especially if a corneal ulcer occurs.

Surgical therapies are usually associated with treating the sequelae of the corneal endothelial cell dystrophies, which include the formation of corneal bullae (blisters) that can rupture and become corneal ulcers.  These can be helped with a contact bandage lens and temporary partial lid closure (temporary tarsorrhaphy) to help protect and support the corneal surface.