Corneal dystrophy is a hereditary and progressive condition that impacts both eyes, often manifesting similarly in each. It primarily affects the cornea, the transparent outer layer of the eye’s front. Notably, this disease isn’t linked to other medical conditions and is quite prevalent among dogs.
The disorder comprises three types of corneal dystrophy, distinguished by their locations: epithelial corneal dystrophy, which disrupts cell formation; stromal corneal dystrophy, leading to corneal opacity; and endothelial corneal dystrophy, affecting the cells lining the cornea.
Symptoms and Types
Epithelial Corneal Dystrophy:
- Potential corneal spasms
- Normal vision
- Circular or irregular white or gray opacities or rings on the cornea
- Onset typically between six months to six years of age
- Progression is slow
- Shetland sheepdogs are prone to this type
Stromal Corneal Dystrophy:
- Vision usually remains normal, but can be reduced with advanced diffuse opacity
- Opacities may appear oval or circular, white, gray, or silver
- Diffuse opacity or annular (doughnut-shaped) opacity may occur
- Occurs in young adult dogs
- Dog breeds predisposed to both epithelial and stromal dystrophies include:
- Afghan hound
- Airedale terrier
- Alaskan malamute
- American cocker spaniel
- Beagle
- Bearded collie
- Bichon frise
- Cavalier King Charles spaniel
- German shepherd
- Lhasa apso
- Mastiff
- Miniature pinscher
- Rough collie
- Siberian husky
- Samoyed
- Weimaraner
- Whippet
Endothelial Corneal Dystrophy:
- Corneal swelling with fluid blisters development
- Vision may be impaired in advanced stages
- Typically affects middle-aged or older dogs, with a possible female predilection
- Affects young animals
Dog breeds predisposed to corneal dystrophy include:
- Boston terriers
- Chihuahuas
- Dachshunds
- May affect other breeds
Causes
Epithelial:
- Degenerative or innate abnormalities of the cornea
Stromal:
- An innate abnormality of the cornea
Endothelial:
- Degeneration of the lining of the cornea
Diagnosis
Your veterinarian will conduct a comprehensive physical examination of your dog, which includes an ophthalmic assessment. Additionally, they will request a blood chemical profile, a complete blood count, an electrolyte panel, and a urinalysis. Providing a detailed history of your dog’s health leading up to the onset of symptoms is crucial.
The use of slit lamp microscopy will greatly assist in distinguishing the type of corneal dystrophy present. A fluorescein stain, a non-invasive dye revealing eye details under blue light, will be applied to check for abrasions and to delineate the cornea’s shape, aiding in the diagnosis of corneal dystrophy. Fluorescein dye facilitates the detection of any corneal ulcers, common in endothelial and epithelial corneal dystrophy. Its diagnostic utility varies: it may not consistently aid in diagnosing endothelial corneal dystrophy and is less useful in diagnosing stromal corneal dystrophy. However, it can be beneficial in diagnosing epithelial corneal dystrophy.
Furthermore, a tonometer will measure the interior pressure in your dog’s eyes to exclude glaucoma as a potential cause of corneal swelling.
Treatment
If your dog has corneal ulcers, they will receive treatment with antibiotic eye medications. Typically, stromal corneal dystrophy does not necessitate specific treatment. For endothelial corneal dystrophy, the use of contact lenses over your dog’s eyes may be recommended. In cases where epithelial corneal tags are present, they may be removed.
An alternative treatment for endothelial corneal dystrophy involves flap surgery of the conjunctiva, which is the lining of the eyeball and the back surface of the lids. While a corneal transplant might be considered, it’s important to note that the results can be inconsistent in their effectiveness.
Living and Management
Your dog is likely to retain some level of cloudiness in its eyes, even after successful treatment. However, if you observe signs of discomfort in your dog’s eyes such as increased blinking or watering, it’s essential to contact your veterinarian promptly, as corneal ulcers may be forming. This occurrence is common in cases of endothelial and epithelial corneal dystrophy.
Despite the presence of corneal dystrophy, your dog’s vision may remain unaffected. Regular monitoring and prompt veterinary attention are crucial aspects of managing your dog’s eye health.
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