Pittsburgh Veterinary Specialty & Emergency Center
INDUSTRY INSIGHT
VETERINARY SERVICES
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DRY EYE IN DOGS
Kara Gornik, DVM, DACVO Ophthalmologist at Pittsburgh Veterinary Specialty and Emergency Center( PVSEC)
Keratoconjunctivitis sicca( KCS), commonly known as dry eye, is a relatively common condition in dogs. Dry eye can occur in any breed, but the Cavalier King Charles Spaniel, English Bulldog, Lhasa Apso, Shih Tzu, West Highland White Terrier, Pug, and Cocker Spaniel are considered to be at the highest risk.
Dry eye occurs when the lacrimal( tear) glands are unable to provide adequate moisture. There are several causes of dry eye in dogs. Most cases are considered immune-mediated, where the animal’ s body destroys the glands because it sees them as foreign, making the glands no longer capable of producing an adequate amount of tears. However, destruction of the glands can also occur secondary to infection, drug toxicity, or a problem with the nerve that goes to the lacrimal gland.
To diagnose the condition, a Schirmer tear test is performed, which involves placing a small strip of paper underneath the eyelid to wick tears along the paper. The paper is left in place for one minute and the distance the water line travels is measured. If the line does not travel far enough, a diagnosis of dry eye is made.
Dry eye causes the eye to become irritated because the tears normally lubricate and protect the eye. Dogs with dry eye often have a red conjunctiva. Many also have a thick mucus discharge. Dogs with this condition are more susceptible to eye infections and corneal ulcers. With prolonged dry eye, the cornea may become scarred and pigmented. Blood vessels invade the cornea as well. All of these components lead to reduced vision, and eventually blindness may occur.
In an effort to stimulate tear production, control secondary infections, and decrease scarring, veterinarians often prescribe several medications to treat all aspects of the disease process. One of the cornerstones of therapy is an immune-modulating drug, a medication that prevents the patient’ s immune system from destroying the glands. An additional benefit of these medications is that they help reduce the number of blood vessels on the cornea and reduce the severity of corneal pigmentation, allowing for better vision as the cornea becomes clearer. Other medications such as topical antibiotics may be used, especially if there is a concurrent corneal ulceration or scratch on the eye. Topical steroids are chosen in some cases to help with the redness, discharge and corneal scarring. Artificial tear gel is extremely important in the management of dry eye, as replacing tears and keeping the eye moist can help minimize the risk of further eye problems. Finally, in cases where the nerve that stimulates tear
production has been damaged, an eye drop, generally placed onto the food, can help improve nerve function.
In cases of dry eye that do not respond to the above treatments, surgery may be recommended. A parotid duct transposition( PDT) is a surgery that can help improve tear production. In this procedure, the duct from one of the salivary glands is moved from the mouth to the eye, so that when saliva is delivered from the gland, it helps to moisten the eye as a tear replacement. This surgery is generally considered a last resort for patients whose dry eye continues to persist despite being appropriately treated. Even after a PDT, patients still require ongoing medical therapy.
Frequent rechecks with a veterinarian are recommended to continue to monitor the dry eye and response to therapy. Routine monitoring of the Schirmer tear test as well as regular fluorescein staining to monitor for corneal ulcerations are required for patients with dry eye. Dry eye generally requires medical management for the duration of the dog’ s life.
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Figure 1: Redness of the conjunctiva around the eye as well as a few corneal blood vessels and mild brown pigmentation on the cornea in a dog with early dry eye.
Figure 2: Severe corneal pigmentation and discharge in a dog with chronic, untreated dry eye.
This Industry Insight was written by Kara Gornik, DVM, DACVO, Ophthalmology Specialist, Board Certified in Veterinary Ophthalmology
On the Job Always interested in veterinary medicine, Dr. Kara Gornik decided to become an ophthalmologist after receiving a research grant in veterinary school to study immunologic receptors in equine eyes. She is published in a number of professional journals and has spoken at many conferences and continuing education events. Her particular clinical interests include golden retriever pigmentary uveitis, the genetics related to ocular conditions, and inherited retinal conditions.
Education Diplomate, American College of Veterinary Ophthalmology Residency, Ophthalmology, Tufts University, Medford, MA Fellowship, Comparative Ophthalmology, Michigan State University, East Lansing Internship, Small Animal Medicine & Surgery, Michigan State University, East Lansing Doctor of Veterinary Medicine, University of Georgia, Athens Bachelor of Science, West Virginia University, Morgantown
Pittsburgh Veterinary Specialty & Emergency Center
South Hills location: 1535 Washington Road, Washington, PA 15301, 724.809.2000 North Hills location: 807 Camp Horne Road, Pittsburgh, PA 15237, 412.536.5248 Web site: PVS-EC. com
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