Dry Eye (KCS) in Dogs: Causes, Symptoms, and Treatment

Dry eye, scientifically known as Keratoconjunctivitis sicca (KCS) or canine dry eye syndrome, is a common eye condition in dogs that can lead to discomfort and even vision problems if left untreated. Keratoconjunctivitis sicca occurs when a dog's tear glands fail to produce an adequate amount of tears or when the tears they produce are of poor quality. Tears are essential for maintaining the health of a dog's eyes. They provide moisture, nourishment, and a protective barrier against dust, debris, and harmful microorganisms.

When a dog's eyes lack sufficient tears, the cornea (the transparent outermost layer of the eye) can become dry, leading to irritation, inflammation, and potential corneal ulcers. 

Just like humans, dogs can experience dry eyes, and it's essential for pet owners to understand this condition, its causes, symptoms, and available treatments to ensure their furry friend's well-being.

Symptoms of Dry Eye in Dogs

Common signs of canine dry eye include:

• Redness: Bloodshot eyes or redness in the whites of the eyes.
• Squinting or Blinking: Dogs with dry eyes may blink or squint excessively to try and alleviate discomfort.
• Discharge: A thick, yellowish-green discharge may accumulate in the corners of the eyes.
• Eye Rubbing: Dogs may rub their eyes with their paws or against objects to relieve itching or discomfort.
• Cloudiness: The cornea may appear cloudy or hazy, indicating a lack of moisture.
• Visible Third Eyelid: Sometimes, the third eyelid, located in the inner corner of the eye, becomes more prominent when a dog has dry eye.

Stages of Dry Eye in Dogs

The stages of dry eye in dogs, also known as keratoconjunctivitis sicca (KCS), typically progress as follows:

Stage	Symptoms
Stage 1: Mild	In the early stages, you may notice slight redness, occasional squinting, and increased tearing due to irritation. The dog's eyes may appear slightly dull, but there is no noticeable damage to the cornea.
Stage 2: Moderate	As the condition progresses, the dog may develop a thick, mucous-like discharge from the eyes. The eyes may become more red, and there might be some corneal cloudiness or opacity. Blinking and squinting may become more frequent.
Stage 3: Severe	In severe cases, the eyes will show significant corneal damage. The cornea may become ulcerated or pigmented, and the dog may develop corneal vascularization (blood vessel growth into the cornea). Vision loss can occur at this stage, and the eyes may appear very red and painful.
Stage 4: Chronic	In chronic cases, the condition is long-standing and has caused permanent damage to the cornea. Scarring and pigmentation can be extensive, and the dog may experience severe discomfort and vision impairment.

What Causes Dry Eye in Dogs?

Several factors can contribute to dry eye in dogs:

• Autoimmune Disorders: The most common cause of dry eye in dogs is an autoimmune disorder known as immune-mediated adenitis. This condition affects the tear glands, leading to reduced tear production.
• Medications: Some medications, such as sulfa drugs, can affect tear production in dogs. If your dog is on long-term medication, consult with your veterinarian to monitor their eye health.
• Genetics: Certain dog breeds are more predisposed to dry eye due to genetic factors. These breeds may have smaller or underdeveloped tear glands.
• Infections: Eye infections can damage the tear glands or the cornea, leading to dry eye as a secondary condition.

What Are the Dog Breeds That Are Prone to Dry Eye?

Some breeds may be more prone to developing dry eye due to their genetic predisposition or anatomical factors. Here are a few dog breeds that are known to be more susceptible to dry eye:

• Cavalier King Charles Spaniel: This breed is known for a higher risk of dry eye, possibly due to their large, prominent eyes.
• Shih Tzu: Shih Tzu are also prone to dry eye, which may be related to their brachycephalic facial structure.
• Pug: Like Shih Tzus, Pugs have a flat face and prominent eyes, which can make them more susceptible to dry eye.
• English Bulldog: Bulldogs, with their brachycephalic features, can be at risk for dry eye.
• Pekingese: Pekingese dogs have a pushed-in face and can be prone to dry eye.
• Lhasa Apso: This breed has long hair that can irritate the eyes and contribute to dry eye.
• American Cocker Spaniel: Cocker Spaniels, especially those with long hair around their eyes, can develop dry eyes.
• Boston Terrier: Boston Terriers may have a genetic predisposition to dry eye.

How to Diagnose Dry Eye in Dogs

Diagnosing dry eye in dogs, also known as canine keratoconjunctivitis sicca (KCS), requires a thorough examination by a veterinarian. Left untreated, it can lead to discomfort, corneal damage, and vision problems. Here are the steps typically involved in diagnosing dry eye in dogs:

The veterinarian will begin by conducting a general physical examination of your dog to rule out other potential causes of eye problems. They may also inquire about your dog's medical history and any symptoms you've noticed.

Schirmer Tear Test

Here's how it's done:

• The vet will place a small strip of special filter paper or a Schirmer tear test strip along the lower eyelid of one eye. This strip will absorb tears for a specific period, usually 60 seconds.
• After the allotted time, the vet will measure how much moisture has been absorbed by the strip. If the amount of tear production falls below a certain threshold, it may indicate dry eye.

Fluorescein Staining

To assess the condition of the cornea (the clear outer layer of the eye), the vet may perform a fluorescein stain test. A fluorescent dye is placed in the eye, and a blue light is used to examine the cornea for any signs of damage or ulceration. Dry eye can cause corneal problems over time.

Ocular Examination

The veterinarian will also examine the eye's overall health, including the conjunctiva, eyelids, and any discharge. This helps in assessing the extent of damage and any complications related to dry eye.

Assessment of Schirmer Tear Test Results

The vet will compare the results of the Schirmer tear test to established reference ranges for tear production. A value below the normal range may indicate dry eye.
The normal value for the Schirmer tear test in dogs can vary depending on the reference range used by the veterinary clinic or laboratory conducting the test. However, in general, a Schirmer tear test result below 15-20 millimeters of wetting per minute is often considered indicative of dry eye in dogs.

If your dog is diagnosed with dry eye, the veterinarian will discuss treatment options, which typically involve the use of artificial tears, medicated eye drops, or ointments to help manage the condition.

How to Treat Dry Eye in Dogs？

The first step is to have your dog evaluated by a veterinarian. They will perform a thorough eye examination, including tear production tests, to confirm the diagnosis of dry eye and determine its severity.

Medications

• Artificial Tears: Lubricating eye drops or ointments (artificial tears) are often prescribed to help moisturize the eye and provide relief from dryness. These drops may need to be administered several times a day.
• Neomycin Sulfate: Neomycin Sulfate drops can help stimulate tear production. They are usually administered once or twice daily.
• Tacrolimus: Tacrolimus ophthalmic ointment (e.g., Protopic) is another immunosuppressive medication that may be used to increase tear production.

Antibiotics

If your dog's eyes have become infected due to dryness, your veterinarian may prescribe antibiotics to treat the infection. Untreated infections can exacerbate dry eye symptoms.

Anti-Inflammatory Medications

Inflammation in the eye may worsen dry eye symptoms. Non-steroidal anti-inflammatory drugs (NSAIDs) or corticosteroids may be prescribed to reduce inflammation.

Eye Cleaning

Keeping your dog's eyes clean is essential to prevent further irritation. Your vet may recommend a saline solution or eye cleanser to remove discharge and debris.

Environmental Changes

Make environmental adjustments to minimize potential irritants:

• Avoid exposure to smoke or other pollutants.
• Ensure your dog is not exposed to wind or drafts.
• Use a humidifier to increase the humidity in the home, especially in dry climates.

Diet

Omega-3 fatty acids, such as those found in fish oil supplements, may help improve the quality of your dog's tear film. Consult your vet before adding any supplements to your dog's diet.

Surgical Options

In severe cases that do not respond to medical treatment, a surgical procedure called parotid duct transposition may be considered. This surgery redirects saliva flow into the eyes to help maintain moisture.

When to Call Your Vet?

Detecting dry eye in dogs early and promptly seeking treatment is crucial. If you observe any issues with your dog's eyes, the recommended course of action is to consult your veterinarian. They will perform a thorough diagnosis and develop a treatment plan as needed.

 Here are some signs and symptoms that should prompt you to call your vet:

• Thick or Opaque Discharge: A thick, yellow, or green discharge from your dog's eyes can indicate an infection or inflammation, which may be associated with dry eye.
• Excessive Blinking or Squinting: If you notice your dog blinking frequently, squinting, or showing discomfort in their eyes, it could be a sign of dry eye.
• Redness and Swelling: Inflamed or red eyes, along with swelling or discharge, can indicate a problem with your dog's eye health.
• Pawing at the Eyes: If your dog is repeatedly pawing at their eyes or rubbing them against objects, it may be a sign of eye discomfort.
• Cloudiness or Ulcers on the Cornea: A dry eye can lead to corneal ulcers or cloudiness. If you notice changes in the clarity of your dog's cornea, seek veterinary attention promptly.

How to Prevent Dry Eye in Dogs?

To prevent dry eye in dogs, it's important to maintain their eye hygiene by gently cleaning their eyes regularly, and ensure they receive a balanced diet with essential nutrients like omega-3 fatty acids. Regular veterinary eye check-ups are crucial, especially for predisposed breeds, to detect and treat issues early. Protecting their eyes from trauma and irritants such as smoke and dust, as well as keeping facial hair trimmed, is essential. Providing constant access to clean water and using humidifiers in dry indoor environments, particularly during winter, can also help maintain proper moisture levels and prevent dry eyes in dogs.

FAQs

Can dry eye cause blindness in dogs?

Yes, if left untreated for an extended period, it can lead to complications such as corneal ulcers and scarring, which can affect a dog's vision and potentially lead to blindness. The primary concern with dry eye is the discomfort and potential damage it can cause to the dog's eyes.

Is the dry eye in dogs hereditary?

As for whether dry eye in dogs is hereditary, it can have a genetic component. Some dog breeds are more predisposed to developing dry eye, and it can be more common in certain bloodlines. Breeds like the Shih Tzu, Cocker Spaniel, Bulldog, and Pug are more prone to dry eye. While genetics can play a role, environmental factors and other underlying health conditions can also contribute to the development of dry eye in dogs.

Is the dry eye in dogs contagious?

Dry eye in dogs is not contagious. It is not a condition that can be transmitted from one dog to another or from dogs to humans. It is primarily a medical condition related to the dog's tear production and eye health.

Can dry eye in dogs be cured?

Mild to moderate dry eye can be effectively treated and potentially cured with timely control and treatment. However, when it progresses to the third or fourth stage, it transforms into a chronic condition that can only be managed through extended care and medication.

Conclusion

In conclusion, dry eye in dogs is a treatable condition, but early diagnosis and proper management are crucial. If you suspect your dog may be suffering from dry eye, don't hesitate to seek veterinary care. With the right treatment, your furry companion can enjoy a lifetime of clear and comfortable vision.