Keratoconjunctivitis Sicca (Dry Eye)


What is it? 
​Keratoconjunctivitis sicca (KCS) or "dry eye" is the failure of the tear glands to produce enough liquid tears to keep the eye moist and healthy. The most common cause for KCS is thought to be an autoimmune reaction. The immune system launches a misdirected attack on the tear glands; the triggering event is unknown. Occasionally, certain drugs may induce a dry eye. In most instances, The American Cocker Spaniel, Bulldog, Lhasa Apso, Miniature Poodle, Shih Tzu and West Highland White Terrier are prone to KCS, although any breed of dog may be afflicted with KCS.
​Most dogs with KCS will have a constant heavy, white or yellow discharge from the affected eye. A dry eye is more prone to bacterial infections, conjunctivitis, and corneal ulcers. Eyes that are dry for several months develop corneal scarring and pigmentation, in severe cases this results in obstruction of vision.

A Schirmer tear test is used to diagnose KCS and to measure response to treatment. A small strip of paper is placed in the conjunctival sac for 60 seconds.  The amount of tears wicked up by the paper in one minute is measured. A normal result for a Schirmer Tear Test is 15-25mm/min in dogs and 7-12mm/min in cats.
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Symptoms
Most pets with KCS will have a constant heavy, white or yellow discharge from the affected eye. A dry eye is more prone to bacterial infections, conjunctivitis, and corneal ulcers. Eyes that are dry for several months develop corneal scarring and pigmentation, in severe cases this results in obstruction of vision.

Treatment
KCS is treated with typically treated with topical medication. Medical treatment can sometimes reverse the autoimmune reaction and help stimulate tear production.  Frequent topical lubrication is also recommended. 

In pets that do not respond to therapy, a parotid duct transposition surgery may be considered.  This surgery involves re-routing the parotid salivary gland duct from the mouth to the eye, so that the eye is lubricated by saliva.

​Regardless of the treatment chosen, KCS is a chronic problem that often requires long-term maintenance therapy.