Keratoconjunctivitis Sicca (KCS), commonly called chronic dry eye, is a common condition seen in dogs but unfortunately is often misdiagnosed. Chronic dry eye is a painful condition that can lead to blindness if not treated properly.[Tweet “Chronic dry eye is a painful condition that can lead to blindness if not treated properly.”]
The medical term keratoconjunctivitis Sicca means inflammation of the cornea and surrounding tissues due to dryness. KCS is caused by a lack of production of the tear film.
Normal tear film in dogs and cats is composed of :
1. Lipid (fatty liquid): Functions to limit tear evaporation, helps keep the tear film on the cornea and prevent it from flowing out of the eye. This layer is produced from glands that line the eyelids.
2. Aqueous (water): Functions to provide nutrition to the corneal, acts as a surface lubricant and removes waste material and bacteria from the cornea. This layer is produced from the lacrimal glands
3. Mucin (mucus): Functions to enhance the spread of the tear film across the cornea. This layer is produced from conjunctival goblet cells.
A deficiency in any one of these components will cause chronic dry eye. The most common deficiency is the aqueous (water) layer.
American cocker spaniel, Bloodhound, Boston terrier, Cavalier King Charles Spaniel, English bulldog, English springer spaniel, Lhasa Apso, Miniature schnauzer, Pekingese, Pug, Samoyed, Shih Tzu, West highland white terrier and Yorkshire terrier are all breeds that are prone to chronic dry eye.
Dogs with chronic dry eye have painful, red and irritated eyes. It’s common to see dogs with this disease squinting or blinking frequently. There is often a thick, yellowish mucous discharge due to a lack of the aqueous (water) portion of the tear film. Scarring of the cornea occurs frequently and looks like a dark film covering the eyes. Vision is reduced if the scarring is extensive. Scratches, ulcerations and infection of the cornea are frequent complications that can occur due to chronic dry eye.
Diagnosis is based on history ,physical exam and clinical signs. The Schirmer Tear Test (STT) is a simple test that can be performed in the exam room to diagnose chronic dry eye. This test uses a special paper to measure the tear production in one minute. Dogs with KCS should also be evaluated for corneal ulcers.
Stimulating tear production and replacing the tear film are the two main goals in the treatment of chronic dry eye.
1. Cyclosporine and Tacrolimus are the two main drugs that can be used to help stimulate tear production.
2. Tear film replacement helps provide lubrication to the cornea until tear stimulants are effective. These medications are available without a prescription and come as solutions, gels and ointments. Below are some examples of some products that can be purchased over the counter.
Artificial tear solutions: These products are helpful in removing debris and mucus from the eye. However, it’s not a great solution for long-term treatment because it needs to be applied frequently to provide adequate lubrication
Cellulose-based solutions: These products stay in the eye longer than artificial tears but still required applying every 4-6 hours. Examples include hydroxyproply and hyaluronate.
Artificial tear solutions containing petrolatum or mineral oil: These products provide long-term lubrication but can results in debris accumulation and are best for patients that have a deficiency in the lipid (fatty) tear film layer. This is a great product for owners that will be absent for long periods of time.
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Dr. Anna was born and raised in Guthrie, Oklahoma. As a teenager, Dr. Anna found her beloved pet dead on the side of the road left to die without any help. That was the moment she decided to become a vet and vowed to help other people and their pets. After a few years of practicing in New Hampshire, Dr. Anna became homesick and decided to return to Guthrie to be with her parents and five other siblings. Family and friends are a major part of our lives which is why we treat our clients at Guthrie Pet Hospital as family. Dr. Anna and her husband do not have children but are very proud pet parents and therefore, treat every four legged friend as part of the family.