KCS (Kertaoconjunctivitis Sicca)
By Dr. Karen Burgess
What is a KCS or dry eye?
KCS, otherwise known as keratoconjunctivitis sicca or dry eye, is a condition of decreased tear production. The eye has several associated glands that produce tears. Tears are necessary to remove foreign substances or debris and to keep the eye lubricated. With decrease in tear production, the eye can become dry leading to irritation and increased discharge surrounding the eyes.
Why do dogs develop KCS?
The most common cause of KCS in dogs is an autoimmune related disease. With immune system disease, the body starts inappropriately attacking something that is normal, in this case the tear producing cells. There may be a genetic predisposition to the development of KCS and many breeds are thus predisposed. Other potential causes of dry eye include a reaction to particular medications or hypothyroidism. Sometimes tear production will appear decreased due to inflammation in other parts of the eye; once the underlying disease is addressed the tear production may return to normal in these cases. Lastly there is a neurologic cause that typically causes a very dry nose on the associated side of the face with the diseased eye.
What does a KCS look like?
Owners may first notice increased ocular discharge with KCS. The eyes may be painful demonstrated as squinting, holding the eyes shut, or excessive blinking. Over time, dogs with KCS are more prone to developing corneal ulcers and scarring which often appears as black pigment on the cornea.
How is KCS diagnosed?
A Schirmer Tear Test (STT) is used to diagnose dry eye. This test involves placing a small strip of test paper under the eyelid and quantifying the amount of tears produced over a minute time. Previous application of any eye medication or drop can affect results of the STT. Additional testing may be done to evaluate the cornea for damage (fluorescein staining), to evaluated intraocular pressure (looking for associated glaucoma), and to evaluate the quality of tears being produced.
What are treatment options for KCS?
The first goal of treatment for dry eye is to replace tears artificially allowing protection of the delicate cornea. This is done by administering a topical tear replacer that is often applied every few hours throughout the day (the more the better). The second goal of treatment is to stimulate the body’s natural production of tears. Tacrolimus and cyclosporine are the most commonly used medications for this and are applied topically at least twice daily. These medications are often compounded or specifically made by the pharmacist for a specific pet. General hygiene is also important, gently wiping the face and eye area to help prevent buildup of debris. Ultimately there is surgery available to treat dry eye if topicals are not an option, but this is not without the possibility of complications.
What is the prognosis with KCS?
With the medications currently available dogs with KCS have a good prognosis for returning to a normal comfortable eye. It is important to understand that treatment is life-long and cure is not expected.