dry eye in dogs

Also called keratoconjunctivitis sicca (KCS), dry eye is a common problem in some dogs. Because it has many underlying causes, a proper diagnosis is essential before it can be effectively treated.  

Dry eye is a relatively common condition in dogs that’s frequently overlooked during routine exams. Its medical name is keratoconjunctivitis sicca (KCS), and it occurs when your dog doesn’t make enough tears to keep his eyes lubricated. Without tears, the dog’s eyes become irritated, leading to redness and discharge. If left untreated, KSC can cause damage to the eyes and eventually even vision loss. Dry eye has many causes, so a correct diagnosis is vital to successful treatment.

Why do dogs get dry eye?

“The most common cause of KCS in dogs is immune-mediated disease,” says holistic veterinarian Dr. Cornelia Wagner. “From a holistic standpoint, it is almost always associated with Blood Deficiency and often coexists in a patient afflicted by allergic dermatitis.” Dry eye arising from immune-mediated disease causes destruction to the tear-producing gland tissue, and although we don’t know why this type of inflammatory reaction occurs, certain breeds are predisposed to it, including the American cocker spaniel, the miniature Schnauzer and the West Highland white terrier.

Although immune-mediated conditions are most often at the root of dry eye, it also has quite a few other potential causes (see below).

Clinical signs of KCS

According to an article in Today’s Veterinary Practice, called “Diagnosis & Treatment of Keratoconjunctivitis Sicca in Dogs”, common clinical signs of dry eye are mucus discharge, mild corneal neovascularization (the invasion of new blood vessels into the cornea from the limbus) and blepharospasm or twitching eyelids. When dry eye is immune-mediated, the eyes look extremely red and your dog may have trouble opening his eyelids. This can often look like a simple case of conjunctivitis.

“Any dog with red eyes and/or discharge from the eyes needs to be seen by a veterinarian,” says Dr. Wagner. “Acute KCS is very painful and could lead to the loss of the eye(s) if not recognized and treated properly.” Other signs of KCS can include recurring eye infections, and a dull or cloudy look to the eye.

Diagnosing dry eye

Because dry eye can have many causes, and may lead to eye damage and vision loss if left untreated, an early diagnosis is of vital importance. In order to determine how dry your dog’s eyes are, your veterinarian will use the Schirmer Tear Test (STT). This test is the cornerstone of quantitative KCS diagnosis.

To perform the test, a strip of specific paper is put just inside the lower eyelid in the outer corner of the eye and left for 60 seconds. The eye’s moisture will wet the paper. At the end of the 60-second period, the height of the moistened area on the paper is measured. A height less than 5mm mean the eye is severely dry.

Treatment varies depending on cause and severity

“Depending on the severity [of a patient’s dry eye], we treat it either with Chinese herbal formulas addressing Blood Deficiency, along with homeopathic eye drops to stimulate tear production; or we combine the herbal therapies with topical treatment, using cyclosporine ointment,” says Dr. Wagner. “We also use acupuncture to influence tear production and address the inflammation and Blood Deficiency.”

“We also use acupuncture to influence tear production and address the inflammation and Blood Deficiency.”

Dry eye should not be treated topically at home without a proper diagnosis of the underlying cause. “I would not encourage anyone to use herbal eye washes or eye drops without talking to a holistic veterinarian first,” says Dr. Wagner. While herbal eye washes are great for preventing infections, they can’t correct dry eye on their own because they don’t address the underlying cause.

If your dog’s eyes are irritated, red, dull-looking and/or exuding a discharge of any kind, the first thing to do is see a veterinarian as soon as possible. Other eye problems can cause symptoms similar to KCS, but either way, a prompt diagnosis is needed before treatment can be determined. Your dog’s eye health and vision are too important to do otherwise.

“Any dog with red eyes and/or discharge from the eyes needs to be seen by a veterinarian.”

Symptom stages in canine KCS

There are typically three stages of clinical signs you should watch for:

  1. Initial – Typically, there is an ocular discharge with mucus and pus, followed by eyelid twitching. An increase in blood flow to the vessels in the eye can also occur, making the eye look extremely red.
  2. Intermediate – An intense mucoid ocular discharge may occur. The cornea may appear cloudy.
  3. Final – Pigmentation occurs, and is typically followed by recurrent corneal ulceration, leading to possible blindness.

Additional causes of dry eye

  • Canine distemper
  • A congenital lack of tear-producing gland tissue
  • Reactions to certain drugs like Sulfa derivative medications.
  • Anesthesia, which temporarily reduces tear function
  • Surgery for cherry eye, which removes the third eyelid’s tear-producing gland
  • Hypothyroidism

A congenital alacrima observed in the Yorkshire terrier, Bedlington terrier, English cocker spaniel, and Cavalier King Charles spaniel can also lead to dry eye.