You may have noticed that your dog or puppy appears to have a metallic or opaque look to the outer layer of each eye, either in the middle or to the edges of the eye. In some breeds it may also appear like a crystalline growth in the eyes, or even as a smoky or smudgy area of the cornea. Any type of eye discoloration that is inherited, bilateral (affecting both eyes), and is not swollen or inflamed is known as corneal dystrophy. This condition is common in many different breeds of dogs and can strike at any age from just a few months old up to senior ages. Typically the condition affecting the dog's vision will slowly progress, decreasing sight in both eyes as the dog matures and ages. In some breeds the progression will be relatively slow while in others the condition rapidly leads to vision loss.
The breeds most commonly affected by corneal dystrophy include Beagles, Shetland Sheepdogs, Airedales, Chihuahuas, Collies, Poodles, Spaniels, Greyhounds, Whippets, Mastiffs, German Shepherds, Samoyeds and Alaskan Malamutes. Each breed will have a unique age of onset typical for the condition as well as a different appearance or type of corneal dystrophy.
In some breeds the corneal dystrophy will be a small, oval shaped opaque "spot" on the corneal of each eye that starts out relatively small and then slowly grows in size and discoloration. In some breeds such as the Mastiff the corneal dystrophy typically has an oval shape and tends to progress very slowly in growth. In Pointers the condition tends to be more of a very fuzzy or grayish colored ring around the cornea.
The corneal dystrophy can involve several layers of the cornea, which will impact on how severe it will be with regards to vision loss. It is thought to be painless for dogs unless there is a break in the outer layer of the cornea, resulting in a possible ulcer that will need to be treated with anti-inflammatories and antibiotics as well as pain management drug therapies.
There is no treatment for the gradual or relatively rapid vision loss due to corneal dystrophy. Unlike cataracts the thickening opaque area cannot be easily removed and in cases where it has been removed it will typically redevelop in a short period of time. There are currently no medications that can be used to dissolve the thickened area, although research is ongoing to try to develop effective ways to control the growth of the tissue that causes the problem.
In many breeds there is current evidence that it is a genetically inherited condition, so any dogs that have corneal dystrophy should not be used in breeding lines. Often this is problematic as many breeds don't develop the condition until later in life, which means that breeding may have already occurred. Report any signs of corneal dystrophy to the breeder you purchased the puppy from and begin to work with your dog help them adjust to their progressive loss of site. Treat any eye ulcers or irritations immediately and discuss the condition with your vet. Dogs with corneal dystrophy can lead happy, healthy lives and it is very important for owners to keep this in mind.