Have you noticed your dog squinting, blinking excessively, or developing red, goopy eyes? You might think it’s just allergies at first, but your pup could be dealing with dry eye. Also known as keratoconjunctivitis sicca (KCS), dry eye in dogs happens when glands around the eyes no longer produce enough natural tears.

KCS can be confused with many other diseases and conditions. Our VRC ophthalmology team explains what causes dry eye, how to spot the signs in your dog, and the treatment options available to restore your pup’s eyes to good health.

Causes of dry eye in dogs

The tear film has several layers, including oil, watery, and mucous layers, that protect and nourish the surface of the eye. When the tear film balance breaks down, the pink tissue lining the eyelids (i.e., conjunctiva) and the clear window over the pupil (i.e., cornea) become dry and irritated.

Dry eye is typically an immune-mediated condition, which means the dog’s immune system attacks and damages the tear-producing glands, decreasing tear production. KCS can happen to any dog, but is mainly seen in small breeds (particularly terriers and spaniels) and typically affects dogs in middle to older age. The condition rarely affects cats.

Other possible causes or contributing factors include:

• Hypothyroidism

• Diabetes

• Cushing’s disease

• Medications (e.g., sulfa drugs)

• Congenital abnormalities

• Chronic prolapsed third eyelid gland (i.e., cherry eye)

• Third eyelid tear gland removal

• Nerve damage

• Ear infections and certain ear medications

Signs of dry eye in dogs

Clinical signs of dry eye in dogs may include:

• Red eyes or visible blood vessels

• Thick, mucoid discharge that keeps coming back after cleaning

• Frequent squinting or blinking

• Pawing at the eyes or rubbing them on surfaces

• Dull, lackluster, or cloudy eye appearance

• Brown/black pigmentation on the cornea

• Red, inflamed conjunctiva (i.e., conjunctivitis)

• Recurrent corneal ulcers

Diagnosing dry eye in dogs

A Schirmer tear test (STT) can help diagnose dry eye and distinguish it from other causes of eye redness and irritation. The test uses a paper strip with a blue dye to quantify tear production over one minute. Results below the normal range indicate insufficient tear production.

Your primary veterinarian can diagnose dry eye and rule out or treat secondary ulcers. However, the STT isn’t perfect, and some dogs need further testing to confirm the diagnosis. A thorough history, physical exam, and blood work can help rule out other factors contributing to your dog’s low tear production.

If your vet suspects dry eye but tear testing appears normal, a referral to our ophthalmology service may be in order. Our team uses specialized equipment to examine the eye’s surface in microscopic detail and determine the root cause of your dog’s red, itchy eyes.

Treating dry eye in dogs

In most cases, dry eye is not curable and requires lifelong treatment. KCS caused by a nerve problem may resolve after several weeks or months. More often, dry eye is chronic but manageable, which means medication can control symptoms, but those symptoms return if you stop treatment.

Dry eye treatment depends on the cause and severity, and may change as your dog’s needs and eye health evolve. The goals are to encourage the body to produce its own tears and to prevent complications, such as corneal ulcers and pigmentation, that can threaten vision.

Treatment may include: – Artificial tears for temporary lubrication and protection – Cyclosporine or tacrolimus eye drops or implants to stimulate natural tear production – Oral or topical pilocarpine to address nerve-related tear issues – Anti-inflammatory eyedrops to soothe irritation and address scarring – Antibiotic eyedrops to treat secondary ulcers or change the eye’s bacterial microbiome – Medications to treat underlying disorders (e.g., diabetes or hypothyroidism) – Parotid duct transposition surgery to move a salivary duct near the eye, allowing saliva to supplement the tear volume – Eye removal or corneal grafting surgery if severe, deep, or infected ulcerations occur

Primary care veterinarians can handle mild and uncomplicated cases of dry eye. However, a veterinary ophthalmologist should direct and monitor treatment in moderate to severe cases, or when first-line treatments don’t work as expected.

Supportive care for dry eye in dogs

You can help care for your dog with dry eye at home by: – Sticking to your pet’s treatment, even if symptoms improve. – Gently cleaning discharge daily with buffered eyewash and a soft, damp cloth. – Keeping windows closed on car rides or using eye protection goggles. – Checking your dog’s eyes regularly for changes in appearance. – Adhering to the recommended recheck schedule. – Talking with your dog’s veterinary team if you have difficulty administering prescribed treatments.

Living with dry eye in dogs

Dry eye can be frustrating for pet owners, especially since treatment is a long-term commitment. With the right treatment plan and trust in your pup’s primary and specialist veterinary teams, most dogs with KCS enjoy reasonably clear vision and a good quality of life.

Schedule a visit with Dr. Zachary Badanes, head of the VRC ophthalmology team, if you notice changes in your dog’s eyes that could indicate a serious condition. Although the occasional red eye may seem minor, it’s important to determine the underlying cause and implement a treatment plan for your dog’s long-term eye health, comfort, and vision.