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Keratoconjunctivitis: Inflammation of the Eyes

Posted December 07, 2014 in Dog Diseases & Conditions A-Z

Keratoconjunctivitis is an awfully long word that basically means any inflammation (“itis”) of both the cornea (“kerato”) or the transparent part of your eye that you see through and the “conjunctiva” -- the pink mucous membrane that covers the insides of your eyelids and attaches to the opaque, white part or sclera of the eye. You may know from your own experience that your eyes are vulnerable to trauma and irritation from things like wind, dryness, infections and foreign bodies. It’s not surprising, then, that your dog’s eyes are also sensitive to developing keratoconjunctivitis.

Bulldog with red eyesWhat are the symptoms of keratoconjunctivitis?
Again, you can probably guess this based on your own experience. The inflammation causes:

  • Redness
  • Swelling of the eyelids and conjunctiva
  • Itchiness (your dog may rub his face and eyes)
  • Pain
  • Squinting (either from pain or from sensitivity to light)
  • Discharge from eyes (clear, excessive tearing to thicker, mucous) that might even ‘glue’ eyelids closed especially after sleeping
  • Cloudy appearance of the corneal surface
  • Decreased visual acuity

Not all symptoms will occur in all cases and the condition may only exist in one eye or both eyes depending on the cause.

What causes keratoconjunctivitis in dogs?
Remember, since this is an “itis,” it can be caused by anything that causes irritation or inflammation to the eye.  Some causes include:

  • Environmental irritants (dryness, dust, smoke, etc.)
  • Allergies
  • Infections like distemper
  • Immune-mediated disorders
  • Keratoconjunctivitis sicca or dry eye

The last one, Keratoconjunctivitis sicca (known as KCS) or ‘dry eye’ is a very common disorder in dogs. Just as keratoconjunctivitis in general can have many causes, so can the more specific KCS. KCS can also be due to a hereditary predisposition (like in Cocker Spaniels, Boston Terriers and other breeds) and often times due to an immune mediated disorder where your dogs own immune system is the culprit1.

As the name, dry eye, implies, the issue in KCS is a lack of adequate moisture/tears in the eye. Normal tears in normal amounts are essential for healthy eyes. Imagine if you had blood vessels running across the surface of your eye. It would be difficult to see properly. That’s why they aren’t there. But nutrients and antibodies and everything else that blood would deliver to your eyes has to get there somehow. That’s what tears do. Without them bad things happen -- more inflammation or infection occurs, the

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.