Pannus (Chronic Superficial Keratitis) in Dogs

This disease is most often seen in German Shepherds but can affect other breeds. It is thought to be related to ultraviolet light but is not a clearly understood condition. It seems to be worse at high altitude and very sunny areas. Pannus is believed to be an autoimmune disease, which in simple terms, means that your dog’s body overreacts to what is happening to the cornea. Starting as a pink tinge to the eye, the disease takes hold causing the eye to become opaque and darken. Eyesight can suffer with blindness occurring if not treated.

Pannus is when a gradual change occurs in your dog’s eye, caused through blood vessels and scar tissue entering the cornea.

• Changes in color to the clear cornea causing whitish, pink or brown discoloration
• Visual impairment 
• White fatty growths appear near the cornea
• Bilateral color changes with scarring
• No apparent pain unless advance stage
• Thickening of tissue over the eye
• Thickening of the eye lining 
• An opaqueness to the eye

Types

German Shepherds, Border Collies and Long-haired Dachshunds are the commonly affected breeds.  Ultraviolet light exposure and high altitude seem to trigger the condition, which usually affects both eyes although they may differ in severity. There is no cure but it can be contained and managed.

Not a lot is known about the cause of pannus but a few of the agreed possible causes are:

• Pannus is thought to be a form of autoimmune disease
• Hereditary condition that can affect all dogs 
• Smoke may contribute 
• Increased exposure to ultraviolet light
• High altitudes and sunny climates

If your dog exhibits any of the above symptoms it is best to take him to the veterinarian clinic to have his eyes checked. You will notice any changes due to the color and alteration of appearance in the eye, so observation is the first and most important part of diagnosis. The specialist will look at the medical history of your dog, the breed (some dogs are more predisposed to pannus that others, for example, German Shepherds) and will observe clinical signs.

Your dog’s eyes may be tested by corneal staining to determine the depth and damage of the disease. But most diagnosis is done on the appearance of your dog’s eye.  To confirm the diagnosis, your veterinarian may suggest that your dog have a veterinary ophthalmologist check the eyes and carryout a comprehensive eye test before prescribing treatment options.

There is no permanent cure available yet for this disease but it can be managed by topical medications. This treatment will be lifelong with constant care keeping the condition under control. Topical steroids suppress the immune system response that triggers pannus. Your veterinarian may prescribe injections of subconjunctival steroids into the growth on the cornea and this treatment can last for up to a month, but you will need to continue it afterwards or use another topical treatment as pannus will flare up again if left alone.

Surgery can be used to remove parts of the diseased tissue and may include the use of extreme cold to freeze it off (cryosurgery). In severe cases, radiation is effective. As there is no actual healing or cure for this condition, you must continue to treat your dog’s eyes to contain it. If caught in the early stages and cared for immediately, your dog will retain most of the eyesight and will live a normal life.

A lot to do with recovery relates to the severity of the condition. If pannus is caught in the early stages, treatment at home with topical medications will control the condition. Your dog will be able to continue life as before. If the condition has advanced your dog may lose the sight in one, or in severe cases, both eyes. Treatment at home consists of the application of topical medications,  with occasional visits to your veterinarian to check on the eyesight and condition of the eyes. Keeping your dog inside during very bright sunny hours is advised as the ultraviolet light seems to aggravate this condition. You can purchase special sunglasses for dogs called Doggles which may help. These glasses are designed specially to fit your dog’s head and ensure comfort.