Keratoconjunctivitis Sicca - aka "Dry Eye"
by Kathy Thom
Kippin was diagnosed with KCS earlier this summer, (Keratoconjunctivitis sicca) buy a board certified opthamologest. We caught it early, and her treatment is going well. Initially we had to use drops to dissolve the ulcers on her corneas, then two types of drops (5 times a day) to help regain natural tear production. (Cyclosporine-A and Ocusol-C with vitamin A.) Her tear production has increased greatly in her right eye and were still working on the left, but that one has gone from a tear production of #2 to #14, normal is above #20.
If dry eye is not treated, usually the cornea will develop ulcers, which are very painful, and the eyeball itself can ulcerate to a point where fluid from the inside of the eye will spill out and the eye can "deflate". Then blindness occurs of course.
Here is a copy of the printed information I was given. by the "Eye Clinic For Animals" in Phoenix, AZ.......
Keratoconjunctivitis sicca (KCS) describes the changes in the eye which result from lack of aqueous tear secretion. To understand the "dry eye" syndrome, it is necessary to understand the normal health of the cornea as it relates to the tear film. The cornea is the clear, outer windshield of the eye but like all living tissue, requires a ready and ample supply of oxygen and nutrients. This is not supplied through blood vessels but through the three layered tear film. The outer most layer is an oily layer supplied by glands in the eyelids. The middle layer is the liquid (aqueous) layer produced by the Lacrimal gland in the upper eyelid and in the third eyelid. This is the layer most often affected in KCS. The inner most layer that is in direct contact with the cornea is a mucus layer produced by glands located in the conjunctival membrane which lines the inner eyelid and covers the globe. KCS allows a break down in the corneal tear film and results in patchy, dry areas across the corneal surface or, in more advanced cases, widespread and severe corneal drying. The dried cornea, deprived of oxygen and nutrients through the tear film, rapidly undergoes destructive changes. This can result in brown pigmentation, scarring, ulceration, and vessel growth across the surface of the normally clear window of the eye.
Diagnosis of KCS
Diagnosis is based on history, clinical signs, and a number of diagnostic procedures. These include the Schrirmer Tear Test which measures the production of liquid tear and florescein stain (a bright green stain) which is used to define breaks in the corneal surface and the rate of tear film breakup. In addition, Rose Bengal Stain (a reddish pink stain) may be used to evaluate the health of the outer layer of the cornea called epithelium. Cytology is always recommended to define the state of health of the conjunctival cells; this has both prognostic and therapeutic value.
Causes of KCS
A number of causes have been documented for KCS. These include hypothyroidism, infections of the lacrimal glands like canine distemper virus, immune-immediated disease complexes that attack the tear secreting glands, and others. In many cases, the cause of the dry eye condition remains elusive but, in general, treatment can still be instituted. Another frequent cause of KCS is a toxic effect produced by some sulfa-containing drugs. Because some of these drugs, however, may be necessary for the treatment of other diseases, it may not be possible to change the patient's medications and, therefore, occasionally the KCS must be controlled despite being caused by other therapies.
Treatment of KCS
There are several considerations in treating KCS. A prime consideration is to reduce the overgrowth of bacteria that is common in the dry eye syndrome. The dry eye patient frequently has buildup of mucous in the cul-de-sacs of the eyelids which is no longer being washed with the balance of liquid tears. This mucus is a media for bacterial growth. These bacteria may not be disease causing bacteria. Topical anti-inflamatories are indicated when corneal staining shows no ulceration. This medication helps reduce inflammation of the conjunctival and corneal surfaces and reduces the long term scarring effects. Corticosteriods cannot be used in the face of ulcers because they may decrease healing speed and enhance the ulcerative process. Artificial tear preparations are always indicated to supplement the deficient tear film; a number of products are available and some products may be recommended over others. In addition to watery preparations, artificial tear ointments are sometimes used to provide prolonged corneal contact overnight and during times that the patient cannot be treated frequently.
New drugs recently developed for the use of treatment of KCS include immune-suppressive agents such as cyclosporine. These preparations have provided some symptomatic relief while other patients have resulted in marked increase in tear secretions. At this point, these drugs are considered to be investigational but offer hope for the future.
Forms of KCS
There are several forms of the dry eye syndrome that we commonly treat. These include partial KCS which results from a slight reduction of tear production, intermittent KCS which is a result of the temporary cessation's of tear secretion followed by periods of normal tear production, complete KCS which is a complete absence of tear secretion, and tempory KCS which is the transient loss of tear production due to a variety of causes.
Most patients with KCS will do well if medications are administered on a timely basis. In cases where medicines cannot be given regularly, surgical technique, such as a "parotid duct transposition", must be considered. In general, with good owner compliance and diligent treatment, no patient need lose eyesight due to the dry eye condition in most cases.