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Keratoconjunctivitis sicca (KCS) or dry eye syndrome is defined as aqueous tear film deficiency over the eye surface. This is also seen in the lid lining. The result is inflammation and severe drying of cornea and conjunctiva. Dry eye is quite common in canines, especially cocker spaniels, Lhasa Apsos, Shih-Tzus, bulldogs, and West Highland white terriers. It is a widely kept belief that females are susceptible to dry eyes than males of the species.
That your dog suffers from dry eye syndrome is a possibility when it blinks excessively and the conjunctival blood vessels get swollen. There could also be a prominent nictitans or third eyelid or chemosis. The eye could discharge pus or mucus and there may be changes in the cornea. This is a chronic disease in the blood cells. There could be ulceration and pigmentation. The incidence of severe disease may lead to complete vision loss, or at best an impaired one.
KCS may occur due to immune-mediated adenitis. This is the most common and it is frequently linked with a number of other immune-mediated diseases. The dry eye syndrome is a congenital defect in Yorkshire Terriers and Pugs. It is also occasionally observed in a number of other breeds. The disease is also observed if the pet suffers traumatic proptosis, a condition which the eyes are displaced from sockets. This happens to post a neurologic disease which interrupts the tear gland nerves.
It is frequently observed that a dry nose is seen on the same side as dry eyes. The condition could be drug induced like the application of atropine and general anesthesia. Toxicity of drugs could also be a cause. A few drugs containing sulfa or etodolac may cause a transient or permanent condition. KCS may also be induced by the physician if the third eyelid is removed. The chances of this occurring rise in the case of susceptible breeds.
Any X-ray machine may also cause dry eye in pets. This happens if the eye comes in close contact with any primary beam that has its origination from a radiology device. Canine distemper virus or chlamydia conjunctivitis due to bacteria could also lead to KCS. The incidence of chronic blepharoconjunctivitis or breed linked predisposition could also be the cause.
The veterinarian will conduct a complete ophthalmological and physical examination on the dog. The doctor will include the background symptoms history and the possible incidents which may have led to such a condition. A non-invasive dye like the fluorescent stain could be used to analyze your pet's eye for ulcerations and abrasions.