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Keratoconjunctivitis Sicca (Dry Eye)

Keratoconjunctivitis sicca (KCS or Dry Eye) results from inadequate production of the water component of tears. There are two main tear glands, beneath the third eyelid and behind the upper eyelid.


There are a number of potential causes in dogs:

·      Dry eye often arises from an immune-mediated inflammation of the tear glands and is common in certain breeds including the shih tzu, English bulldog and West Highland White terrier

·      Canine distemper virus infection can cause KCS.

·      Congenital underdevelopment of the tear glands can lead to KCS very early in life, most commonly in the Yorkshire terrier.

·      Trauma, corneal ulceration, and extrusion of the eye as a result of injury may result in KCS, usually on one side.

·      Damage to the facial nerve, which activates the tear glands, can cause KCS and usually arises from chronic ear disease.

·      Removal of a loose (prolapsed) third eyelid tear gland may predispose to KCS later in life.

Clinical Signs

Signs are related to the result of a dry and itchy eye, with redness, increased blinking and squinting, and a thick mucoid discharge.

The cornea may become pigmented and scarred, with decreased vision. 

The dog may rub the eye and corneal ulceration may occur.

Diagnostic Tests

KCS may be tentatively diagnosed based on clinical signs and confirmed by measurement of tear production using the Schirmer tear test.  A thorough examination of the eyes is conducted to rule out other causes of pain and redness such as glaucoma or lens luxation.


The main goal is to increase tear production.  

Drugs such as cyclosporine and tacrolimus protect any remaining active tear gland tissue from further immune-mediated damage.  They are administered up to several times a daily, and treatment is often life long.  Tear production may increase within a few weeks, but it can take as long as three months for a response to be seen.  Unfortunately not all patients will respond to these drugs as the tear glands may have been irrepairably destroyed prior to treatment.

Artificial tears are used to keep the eye well lubricated.  They come in various forms, but at Acorn we advise use of the gels which evaporate at a slower rate from the eye surface, and yet still allow good vision.

Follow up care includes periodic checks, with repeated tear tests, throughout the animal’s life.  Medications often require adjustments to maintain good surface health of the eye.  The key to managing the condition is continuous and diligent treatment by the owner.

KCS is usually a chronic disease that may be controllable but is not often curable.  The prognosis for eyes that respond to tear stimulants is good.