Keratoconjunctivitis Sicca (KCS) “Dry Eye Syndrome”
WHAT IS KERATOCONJUNCTIVITIS SICCA?
KCS is a lack of tear production, which results in inflammation and compromised health of the cornea and conjunctiva. This is most often a disease that affects both eyes, and is seen in a variety of breeds. The tear film is an important part of maintaining a healthy cornea because it provides the oxygen and nutrients it needs. A normal tear film is made up of three layers. An oily layer produced by glands in the eyelids, a liquid or aqueous layer produced by the lacrimal (tear) glands and a mucus layer produced by cells in the conjunctiva. A decrease in production of the aqueous layer results in dryness of the cornea and an increase in mucus in and around the eyes. With the breakdown of the tear film the cornea is deprived of oxygen and nutrients and undergoes rapid changes. The changes can include corneal ulcers, scarring, and deposition of brown pigment. KCS is an irritating and uncomfortable disease for your pet and if not treated can lead to blindness. There are medications to control this condition, but as of yet there is no cure.
WHAT ARE THE CAUSES OF KCS?
There are many causes of KCS, but the majority are considered to be “immune-mediated”. For reasons unknown the body attacks it’s own tissue. Some other causes are drug-induced, trauma, and some systemic diseases such as distemper.
ARE CERTAIN BREEDS OF DOGS PRONE TO KCS?
Yes. The American Cocker Spaniel, Bulldog, Lhasa Apso, Miniature Poodle, Shih Tzu and West Highland White Terrier are predisposed to develop KCS, although any breed of dog may be afflicted with KCS.
WHAT ARE THE CLINICAL SIGNS, AND HOW IS IT DIAGNOSED?
In the early stages of the disease a clear discharge from the eyes may be noted. As the disease progresses the discharge becomes a thick sticky mucus with a yellow to green appearance and is often mistaken by the owner as “an eye infection”. The eyes become red and squinting is often present. In animals with a rapid onset of KCS corneal ulcers may develop. In chronic cases vascularization and pigmentation of the cornea occurs.
Diagnosis is based on the clinical signs along with the results of a Schirmer tear test and fluorescein staining. A Schirmer tear test is a small strip of special paper placed under the eyelid for 60 seconds to measure the liquid layer of the tear film. Fluorescein stain is a green dye that is used to detect the presence of corneal ulcers.
HOW IS KCS TREATED?
KCS is initially treated with eye medications to lubricate the eye and to improve tear production. In rare cases that do not respond to medical therapy, surgery may be recommended. A parotid duct transposition 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, KCS is a chronic problem that often requires long-term maintenance therapy.
It is also important to keep the eyes and the face clean.
WHAT IS PAROTID DUCT TRANSPOSITION?
Not producing adequate tears to maintain corneal and conjunctival health can be very painful and can lead to blindness. If medical therapy is insufficient, a parotid duct transposition can be performed.
HOW DOES THIS SURGERY WORK?
A salivary duct that normally opens into the mouth is transpositioned, that its opening lies within the conjunctiva. The saliva of that salivary gland now lubricates the eye. A general anesthesia is necessary for this procedure.
WHAT HAPPENS AFTER THE SURGERY?
Since saliva is only produced by stimulation, we recommend feeding your pet small snacks multiple times a day. Each time your dog will salivate and lubricate the eye. It is possible that excess saliva runs down the face, causing wetness. It is necessary that you clean and dry the face regularly to prevent dermatitis. A short haircut can make things easier.