Keratoconjunctivitis sicca (otherwise known as KCS or "Dry eye syndrome") results from insufficient tear production. The cause of dry eye is often unknown but some known causes include: congenital disorders, infections (canine distemper virus), drug-induced (sulfa antibiotics, Etogesic), removal of the lacrimal gland of the third eyelid ("cherry eye"), and hypothyroidism. The disease is seen commonly in certain breeds such as the Cocker Spaniel, Shih Tzu, Lhasa Apso, Bulldog, Schnauzer, and West Highland White Terrier.
The clinical signs of dry eye include: heavy mucus production, redness, rubbing at eyes, cloudy eyes, corneal ulcers, and even general lethargy. After an extended period of dryness, the surface of the eye (cornea) begins to develop pigmentation and blood vessels, often causing diminished vision.
Treatment goals for dry eye include stimulation of tears, lubrication, and decreasing the scar tissue. In the last few years, the use of Cyclosporine and Tacrolimus has made an incredible difference in the successful treatment of KCS. New lubricants have also helped in keeping the patient comfortable. Often the renewed tear production is dependent on the presence of the medications, so once a medical treatment plan is started, it is important to continue the medications as directed, and crucial that you have your dog checked as directed to monitor treatment success.