KCS in dogs is also known as dry eye because the condition involves the lack of sufficient tear production. Tears are produced by glands around the eyes to protect the eyes from debris, bacteria, allergens, etc., and they help to lubricate the structures around the eye. Without sufficient tears, eyes can become reddened, dry, and painful. Thick green or yellow mucoid discharge develops due to the lack of the watery component in tears.
KCS can be inherited and affects many dog breeds such as Shih Tzus, Lhasa Apsos, Cocker Spaniels, Boston Terriers, English Bulldogs, Pugs, and Yorkies. There are also certain immune-mediated disorders that attack the tear glands and thus limit tear production. Viral infections like distemper and certain medications like sulphonamide drugs can also impair tear production.
KCS is easily diagnosed via Schirmer tear testing. A small piece of paper is placed near the lower lid of the eye, and then an assistant will close your dog’s eye. The paper is left in place for 60 seconds, and when tears are naturally produced, a small blue dye line on the metered paper strip will move downward.
If the dye line does not move past 15 millimeters, your dog may have a dry eye. Treatment involves the twice-daily use of an ointment to help increase tear production. Eye lubricants are also essential.