"Dry Eye” (Keratoconjunctivitis Sicca) in Dogs

Have you ever had dry eyes? Imagine what it must feel like to have them over the long term! As it turns out, tears are important – and not just for crying. Tears lubricate the eyes to help them stay comfortable, and protect the eyes by flushing away irritants, infectious agents and waste products. It follows that disruptions to tear production, as with dogs experiencing “dry eye”, are not only painful, but also compromise eyesight and can even lead to blindness.

To avoid confusion, the condition commonly called “dry eye” in dogs will be referred to in this article by its proper name, keratoconjunctivitis sicca (KCS). 

What is KCS?
KCS is a disease of the tear glands that leads to insufficient tear production. There are many possible causes of KCS, the most common being destruction of the tear glands by the dog’s immune system. 

Vets aren’t sure what causes this, but it is thought to have a genetic component as certain breeds are at higher risk for the condition. These include the Shih Tzu, American cocker spaniel, Pug, Cavalier King Charles spaniel and West Highland white terrier.

Less common causes include:
•    Certain medications
•    Disorders of hormones (e.g. diabetes, hypothyroidism)
•    Certain infections
•    Damage to the nerve that supplies the tear glands (e.g. from trauma) 

What are signs of KCS?
Common signs are listed below:
•    Squinting or holding eyes closed
•    Excessive blinking
•    Redness of the whites of the eyes
•    Dry, dull eye surface that may appear greyish or brownish (this is due to scarring of the eye surface, which contributes to loss of vision)
•    Yellow to green discharge that sticks to eye surface

How is KCS diagnosed?
Vets often start by taking your pet’s history and performing a physical examination. A Schirmer tear test, which utilises a small wicking piece of paper to measure tear production, is often performed if KCS is suspected.

Vets may also perform other specialised tests to evaluate your dog’s eyes:
•    They may examine your dog’s eyes with an ophthalmoscope to evaluate the deep structures within.
•    A special dye may be dripped into the eyes to check for corneal ulcers (scratches on the eye surface that are common in dogs with KCS).
•    Your vet may use a tonometer check the pressure inside your dog’s eyes.

How is KCS treated?
Dogs with KCS are frequently treated with cyclosporine or tacrolimus eye ointment to stimulate tear production. Artificial tears are often also prescribed to lubricate and protect the eyes. If concurrent infection is present, antibiotic eye drops or eye ointments may also be used.

Treatment is typically required for life. Surgery may be an option if your dog does not respond to medical treatment or if you are unable to apply the medications, although referral to a specialty facility may be required. 

It’s important to note that dogs who have already lost any amount of vision may not recover their sight even with treatment, as scarring of the eye surface cannot be reversed. However, with consistent treatment to minimise eye pain and discomfort, dogs with KCS can still enjoy a good quality of life.

Thank you for reading and we hope the information in this article has been useful for both you and your pet. Please speak with your veterinarian if you have any specific queries about your pet’s health.