Keratoconjunctivitis Sicca (KCS) in Cats


Overview of Keratoconjunctivitis Sicca in Cats

(also known as “Dry Eye”) 

Keratoconjunctivitis sicca (KCS) is a medical term used to describe a condition of decreased tear production. The term technically means “inflammation of the cornea and conjunctiva from drying.” When the watery part of the tears is not produced in adequate amounts, the eye becomes chronically inflamed, and scarring of the cornea may lead to a decrease in vision. Another commonly used term to describe this disease is “dry eye.”

Below is an overview of Keratoconjunctivitis Sicca (KCS) in Cats followed by in-depth information on the diagnosis, treatment and detailed medication information. 

The most common cause in cats is an infection of the eye with feline herpesvirus. Other causes include chronic inflammation of the conjunctiva for other reasons, a rare side effect of certain medications (such as sulfonamide drugs), removal of a prolapsed gland of the third eyelid, trauma to the tear glands, and certain neurological disorders. The disease may affect one or both eyes.

If left untreated, KCS is a potentially vision threatening disease. It may lead to painful corneal ulcerations in the acute stage of the disease. In chronic KCS, vision may be impaired because of scarring of the cornea.

What to Watch For

  • Chronic redness of the eye
  • Chronic discharge that may dry to a dark red-brown color
  • The development of a film over the eye
  • Prolapse of the third eyelid over much of the cornea
  • Diagnosis of Keratoconjunctivitis Sicca (KCS) in Cats

    Veterinary care includes diagnostic tests and subsequent treatment recommendations.

  • A thorough physical examination is an important part of diagnosing the cause of the KCS. The disease itself is confirmed by examination of the eye.
  • A Schirmer tear test is performed to determine the amount of watery tears produced by the eyes.
  • In addition, fluorescein staining of the eye is also performed to detect any corneal ulcers.
  • The degree of corneal cloudiness and scarring are assessed and the interior of the eye is also examined.
  • Treatment of Keratoconjunctivitis Sicca (KCS) in Cats

    The intensity of the treatment depends on the severity of the disease. It may include one or more of the following medications:

  • Application of 0.2% cyclosporine ointment twice a day
  • Artificial tear solution applied often during the day
  • Artificial tear ointment applied one to four times daily
  • Antibiotic ointment or drops if a corneal ulcer or infection are present
  • Antibiotic-corticosteroid drops or ointment in cases of chronic KCS
  • Topical anti-viral medications if an active infection with herpesvirus is suspected
  • Surgery rarely in unresponsive cases
  • Home Care and Prevention

    Once diagnosed, home care is an important part of treatment. Keeping the eyes clean and free of discharge can be challenging. Eye discharge is common and can be very sticky and hard to remove. Applying a warm compress to the eye for a few minutes may make it easier to remove the discharge. The discharge may also be removed from the eye by carefully rinsing the eye with an irrigating eye solution that can be bought over the counter at a drug store. Some cats do not tolerate eye washes, but do accept the warm, wet compresses.

    Apply all medication as directed, and notify your veterinarian if you are having difficulty treating your pet. When treating your animal with both drops and ointment, use the drops first, followed by the ointment.

    Monitor the eye for changes such as increased discharge, squinting or redness, or if your pet starts rubbing or scratching at his eye. Notify your veterinarian immediately.

    It is difficult to prevent KCS but early treatment is crucial. It is very important to take your pet to your veterinarian when you notice persistent discharge and redness. When diagnosed early in the disease, the long-term prognosis for vision is much better than when the KCS is diagnosed in a late stage of the disease.

    In-depth Information on Keratoconjunctivitis Sicca (KCS) in Cats

    Keratoconjunctivitis sicca is an eye disease precipitated by a lack of watery tears, as described in the breakdown of the words:

    kerato- (cornea, which is the clear, transparent front of the eye)
    -conjunctiv- (conjunctiva, which the delicate membrane lining the eye)
    -itis (inflammation)
    sicca (dryness of the eye)

    So, it is an inflammation of the cornea and conjunctiva secondary to dryness of the eye.

    As the watery part of the tear film diminishes, the eye tries to compensate by making more mucousy material. In addition, inflammation of the surface of the eye also stimulates the production of more mucous.

    There are other eye diseases that may resemble keratoconjunctivitis sicca. It is important that an accurate diagnosis is made early in the disease because the treatments vary depending upon the eye disease present.

    Diseases that can appear similar to KCS include:

  • Conjunctivitis. Conjunctivitis is inflammation of the tissues that line the eyelids and cover the eye. Clinical signs of conjunctivitis include increased tearing, discharge, redness and sometimes squinting. There are many causes for conjunctivitis. (See the Client Education article on Conjunctivitis.) With most forms of conjunctivitis, the tear production is normal or high.
  • Corneal ulceration. An abrasion of the cornea causes discharge and redness of the eye. The onset is usually acute and the eye is painful. A corneal ulcer is diagnosed by applying fluorescein stain to the eye. The eye only takes up stain if ulceration is present. Corneal ulcerations may also occur as a result of KCS, especially shortly after the onset of KCS. It is important that the tear production is measured when a corneal ulcer is present. See the Client Education article on Corneal Ulceration.
  • Other forms of keratitis. In the cat, there are several forms of corneal inflammation that may appear somewhat similar to the corneal changes associated with KCS. It is believed that these disorders may also be caused by feline herpesvirus. They include eosinophilic keratitis, stromal keratitis and corneal sequestration. See the Client Education article on Corneal Sequestration.
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