Dry Eye or KCS (keratoconjunctivitis sicca)

The term "dry eye" is often used to describe keratoconjunctivitis sicca (KCS) because the condition causes a loss of tear production. Inflammation of the cornea (keratitis) and conjunctivae (the eye membranes) is termed keratoconjunctivitis, while sicca means dry. Although this condition occurs in both dogs and cats, it is rare in cats. It is most common in certain dog breeds including Lhasa apso, Bulldog, Cocker spaniel, and some of the terriers. Thought to be an inherited tendency in some breeds, in other cases it appears to be immune-mediated disease where the body sends out immune response against the glands that produce the tears. Trauma to the nerve supplying the gland, or to the gland itself can also interrupt tear production.

The drying of the surface of the eye (cornea) and the tissue that surrounds the eyeball (conjunctiva) results in inflammation, and secondary infection usually becomes evident as the protective surface layers are damaged and weakened. This is a painful eye condition. Discharge, swelling of the eyelids, red eye membranes, rubbing of the face, and sensitivity to light are some of the symptoms that may be noted. The eye(s) may be swollen shut due to eyelid spasms. If left untreated, KCS can permanently affect vision.

The keratitis often progresses to a corneal ulceration or a loss of the protective layers of the cornea covering the eye surface. Eventually, new blood vessels form right on the usually transparent cornea, and sometimes pigmentation develops there as well.

A key test for diagnosis is the Schirmer tear test, a simple way to measure tear production. The test can be done right on the examination table. Small paper strips are inserted into the gap between eyelid and eye where tears normally pool and are used to measure tear progression along the strip. In dry eye, there is reduced tear movement up the test strip. Other tests such as bacterial culture and sensitivity, and fluorescein dye test to assess corneal ulcers may also be performed.

Topical eye treatments such as local immune modulators, antibiotics, and lubricants are prescribed, and it is important to attend recommended follow-up appointments at your veterinary facility to allow professional assessment regarding adequacy of the healing process. Sometimes, treatment is required for life.

If your pet is experiencing any of the eye problems mentioned above, see your veterinarian for assessment. Many conditions can mimic dry eye, but regardless of cause, all eye problems should be attended to promptly to help ensure the best possible prognosis.