Dry Eye (KCS)

Hey Doc, my dog has red eyes that really itch. They look like the eyes are made from velvet. They are always dull or crusty or "goopy". Can you help him?

Approximately 1% in the dogs presented to veterinary colleges in North America have a condition called "dry eye". We see this condition in older dogs a few times a month. The $30 dollar name for "dry eye" is Keratoconjunctivitis sicca (KCS)

The causes:

Tears are required to lubricate the cornea and remove any debris or infectious agents that may contact the eye. The tear film is a mixture of mucus, fatty liquid and water and are produced in the lacrimal glands and nictitans glands.

Any condition that impairs the ability to produce adequate amounts of tear film can result in "dry eye". Some of the common causes of KCS include:

·         Immune-mediated diseases that damage the tear producing glands. This is the most common cause of KCS and is poorly understood. The body's immune system attacks the cells that produce a portion of the tear film resulting in decreased production. This is thought to be an inherited disorder.

·         Systemic diseases such as canine distemper virus or feline herpes virus infections.

·         Medications such as certain sulphonamides (sulfa drugs).

·         Hypothyroidism

The breeds most affected by dry eye are:

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

Yorkshire terrier

That doesn't mean other breeds can't be affected. Also consider "mixed breed" dogs that are partially part of the above breeds.

The Clinical Signs:

Most dogs have painful, red and irritated eyes. They often squint, blink excessively or hold the eyes shut. There is often a thick, yellowish, mucoid discharge present as a result of the decrease in the aqueous (watery) component of the tear film.

 
The eyes often have a dull, lusterless appearance due to the corneal drying. KCS most commonly affects middle aged to older dogs. Both eyes are usually affected although one eye may appear worse than the other.


The Diagnosis:

Diagnosis is based on medical history, clinical signs and decreased tear production tests. The most common tear production test is the Schirmer tear test (STT). This simple test uses a special wicking paper to measure the amount of tear film produced in one minute. Additional diagnostic tests that may be performed include corneal staining to check for corneal ulcers, intraocular pressure (IOP) to determine if glaucoma is present and tear duct examination or flushing to ensure normal tear drainage.

The Treatment:

The treatment of "dry eye" has two objectives: to stimulate tear production and to replace tear film, thereby protecting the cornea. There are two commonly used ophthalmic medications to stimulate tear production, cyclosporine and tacrolimus. Both are easily placed in the eyes once or twice daily. These drugs are very safe and most pets improve dramatically with their consistent use.

Gently cleaning the eyes several times a day with a warm, wet washcloth will help your dog feel better and may help stimulate tear film production. We will demonstrate the correct way to administer your pet's medications and address any questions you may have about caring for your pet's condition.


The Prognosis:

With today's tear stimulating drugs, the prognosis for dogs diagnosed with KCS has never been better. "Dry eye" requires life long medical care. With diligent attention and monitoring, most dogs are able to enjoy a pain-free life.

The Providence Veterinary Hospital Blog is a publication of Peter Herman, VMD, at the Providence Veterinary Hospital, 2400 Providence Ave. in Chester, PA. Contact Dr. Herman at 610-872-4000 or visit us at http://www.providencevet.com. Some of this Blog is based on material written by: Ernest Ward, DVM