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5 Striking Signs of Pannus in Dogs You Should Know

Pannus, also called chronic superficial keratitis (CSK) is an autoimmune disease that causes inflammation of the cornea.

Although all breeds can be affected, you’re more likely to see it in middle-aged German Shepherds, Belgian Tervurens, and Border Collies.

This condition is a progressive disease that, if left untreated, can cause severe damage to the eye. This damage creates scar tissue that causes severe vision impairment.

Can Autoimmune Disease Cause Pannus?

There are more than 90 known conditions that are categorized as autoimmune diseases.

These diseases primarily trigger your immune system to attack healthy cells accidentally.

Instead of attacking bad cells, the immune system turns on itself and goes after otherwise healthy cells and organs.

Although the full extent of what causes Pannus isn’t fully understood, experts point to genetic predisposition and environmental factors like those that are listed below.

Pannus in dogs can lead to blindness if not treated.

Pannus in dogs can be aggravated and/or triggered by other things, including:

Ultraviolet light (Common)

Veterinarians and medical researchers agree that exposure to ultraviolet rays can worsen Pannus in dogs.

There are 3 different types of ultraviolet radiation:


UVA is a long-range radiation that is not as “energetic” as UVB and UVC.

It can penetrate visible skin on dogs and can negatively affect the eyes. These rays can harm your dog’s central vision. The earth’s ozone layer filters much of the UV rays; however, up to 95% of UVA makes it through.


UVB is a short-wave UV radiation that can penetrate the outer layer of the skin and is responsible for most skin cancers. Only about 5% of this type of radiation makes it to the earth. The remainder is absorbed by the ozone layer.


Without our protective ozone layer, this dangerous ultra-violet radiation would cause serious consequences for life on earth.

It’s easy to understand how harmful rays of the sun can aggravate an eye condition like Pannus.

How to Protect Your Dog’s Eyes From Dangerous Ultra-Violet Rays

There are ways to help ease your dog’s discomfort. Affected dogs should have limits on their exposure to bright sunlight.

Walks should be reserved for evening, early mornings, or in shaded areas.

Use UV sunglasses:

Some veterinarians are now recommending that Rex Specs goggles be used in conjunction with medication to keep the condition from worsening over time.

Smoke from fire-burning stoves, fireplaces, cigarettes, etc., are all considered irritants to the eyes.


Air pollution doesn’t cause Pannus in dogs, but it can aggravate the condition.

Pollutants can cause dry eyes, cause excessive squinting of the eyes, and can motivate your dog to paw and scratch at the sensitive cornea more than usual.

High altitude

Dogs living at higher altitudes have a higher risk of developing the condition due to increased UV exposure. Similarly, dogs living in areas with a high UV index are at risk.


Diagnosis is purely based on signs and medical history.

There are some holistic practitioners who believe that certain allergies (food, environmental, etc.) may cause or worsen Pannus in dogs.

Pannus in dogs must be treated for life

Diagnosis of Pannus in dogs

To rule out other eye conditions, your vet-doc may perform the following tests:

  • Corneal staining with fluorescein
  • Biopsy of the cornea
  • Schirmer tear test which checks for tear reduction/deficiency
  • Checks for glaucoma, i.e.,  Intraocular pressure testing (IOP)

Treatment Options

Pannus is controllable but can not be cured entirely.

Treatment will stop the disease from developing to more advanced stages and may reverse some of the damage.

Treatment may include:

  • Antibiotics: Medications to treat any secondary bacterial infections or drugs to suppress the immune system
  • Surgery: Only in cases where your canine companion is blind, the top layers of the cornea can be removed
  • Cortisone: The type of cortisone used could be topical steroids applied on the skin or injected by your veterinarian.
  • Radiation: may be an option for chronic and advanced Pannus
  • Eye Drops: Veterinarians may prescribe eye drops (topical corticosteroids) such as dexamethasone, prednisone, or cyclosporine.

Prognosis of a Dog With Pannus

Most cases respond well to medication, but lifelong treatment is necessary.

Some dogs will need a referral to a board-certified veterinary ophthalmologist for more advanced treatment.

In severe cases, advanced surgery may be recommended to remove the scar tissue associated with the Pannus to improve the pet’s vision.

Failure to give the prescribed medication can worsen the condition.

You should always follow your veterinarian’s instructions in the case of Pannus.

5 Clinical Signs of Pannus in Dogs You Should Know

1. Pink Film

In the early stages, you might notice a pink film covering the eye.

2. Opacity

You may notice what looks like a whitish or opaque discoloration in the cornea.

3. Third Eyelid Thickening

The “third eyelid” is called the nictitating membrane and is not always easily seen. You’ll find it in the corner of your dog’s eye, particularly if there is any inflammation in that area.

4. Excessive Tearing

Dogs often have stained fur because of excessive tearing.

In many cases, the tearing is nothing to be concerned about. However, if you notice other signs of problems with the eyes including discomfort (dog pawing at the area, rubbing on the floor, etc.), you should have it checked by a veterinarian.

5. Visual Impairment

Dogs have a way of tricking their owners into believing they can see when, in actuality, they are having vision problems.

Signs of problems could include bumping into furniture, loss of depth perception, more hesitant in low light or in blinding sunlight.


Cyclosporine vs Tacrolimus Eye Drops for Dogs


Pannus, also well-known as Chronic Superficial Keratitis, causes inflammation of the cornea. It will affect your dog’s eyesight/vision, but is seldom painful.

If left untreated, Pannus can result in blindness.

Unfortunately, the progression of the disease can move quickly or slowly.

Any signs of vision impairment or changes to your dog’s eyes should be treated by a licensed veterinarian as soon as possible.

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“Pannus or Chronic Superficial Keratits (CSK) in Dogs – ECA.” ECA, Accessed 24 Apr. 2023.

“Canine – Pannus.” Canine – Pannus, Accessed 24 Apr. 2023.

“Chronic Superficial Keratitis or Pannus in Dogs.” Animaleyeinstitute, 3 June 2018,

VCA Hospitals

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