Eye infections in dogs

Watching your beloved pet paw at red and swollen eyes is upsetting. While eye infections in dogs aren’t always dangerous, they can be extremely serious. Because of this, it’s important to consult your vet when you notice symptoms. Putting off treatment isn’t just delaying relief for your dog’s discomfort — it can lead to more significant issues, like pain, loss of vision, and the need to surgically remove the eye.

Conjunctivitis, or pink eye, targets the mucous membrane lining the eyelids and eyeball. Keratitis affects the eye’s clear outer layer, the cornea. Uveitis affects the eye’s inner structures. Blepharitis is an infection or inflammation of the eyelids. The eyelids and tear glands may also become infected. Tear gland issues, eyelid abnormalities, and trauma can also lead to infections.

Spotting the first signs of an eye infection makes getting early vet care for your pup possible. Some common symptoms to watch for:

• Squinting, blinking, and light sensitivity
• Keeping the eye closed
• Pawing or rubbing at the eye
• Redness and swelling
• Excessive tearing
• Thick, colored discharge

Dogs commonly experience eye infections, which may result from any of the following:

• Bacterial infections. Staphylococcus and Streptococcus species are frequent bacterial triggers of an infection and may cause a thick, greenish discharge.
• Viral infections. Distemper and canine herpesvirus are common culprits of eye issues. They often cause eye infections along with other respiratory problems.
• Allergies. Pollen, dust mites, and smoke can trigger redness, itching, and watery eye discharge.
• Foreign objects or trauma. Debris in the eye or physical trauma can cause inflammation, corneal ulcers, and secondary infections. 
• Tumors.  Eyelid tumors in dogs may be malignant or benign and tend to be easily removed surgically. Tumors that affect the conjunctiva of dogs grow faster and require more extensive surgery to remove. Orbital tumors in dogs are more serious but not as common. They can push the eyeball forward and cause swelling throughout the eye structures. Treatment includes extensive surgery or even removal of the eye as well as the possibility of chemotherapy. 
• Parasites and fungus.  Occasionally, dogs experience eye problems when spores of fungi such as Aspergillus or Cryptococcosis invade the eyeball. Flies can transmit the eyeworm (Thelazia californiensis) to a dog’s tear ducts or conjunctiva. This parasite is found only in the western U.S., as well as in Europe and Asia. 
• Eyelid abnormalities.  Injuries and infections may cause eyelid and eyelash abnormalities, including entropion. Entropion occurs when the edges of the eyelid turn inward, causing eyelashes and fur to rub against the eye surface. It is the most frequently inherited eyelid defect in certain dog breeds.

The cause of your dog’s discomfort may be simple or complex, but only a vet can diagnose the problem. A vet will conduct a thorough eye exam and may perform some (or all) of these tests based on your dog’s symptoms:

• Fluorescein stain.  Your vet applies a yellow dye in each eye, then uses a fluorescent blue light to look for a corneal ulcer.
• Schirmer tear testing (STT). The STT tests for a decrease in tear production (dry eye syndrome), which may lead to inflammation of the surface of the eye as well as the tear glands. Your vet will insert a small piece of paper under the lower eyelid and hold it in place for one minute, then measure the amount of tear production. 
• Tonometry. Tonometry measures the amount of pressure inside the eye using a tonometer. Elevated pressures in the eye can result in glaucoma, which is painful and may result in blindness. 
• Bloodwork. Bloodwork may be recommended depending on the issue and severity of the other tests, or to look for underlying diseases like distemper. 

Treatment for eye infections depends on the underlying cause. Vets will remove any foreign bodies and treat any resulting irritation or infection. Topical antibiotic eye drops and ointments can effectively treat most bacterial infections. In contrast, viral infections need supportive care to manage symptoms until the virus runs its course.

In some cases, topical corticosteroids may be used to help decrease inflammation in the eye (but should never be used in dogs with corneal ulcers). It can be tricky to get drops into your dog’s eyes, especially when they have pain and irritation, but the tips in this video can increase the odds of being successful. Many dogs must wear a plastic cone around their head and neck to prevent them from rubbing their eyes and causing more problems.

Allergies are an infrequent cause of eye issues in dogs and are more likely to lead to skin issues. If your dog’s itchy, red eyes are linked to an allergen, however,  your vet may prescribe antihistamines, corticosteroids, or newer and more effective meds such as Apoquel and Cytopoint.

Don’t let eye problems cloud your pup’s vision. Get prompt vet care once you spot the first signs of an eye infection to ensure your furry friend gets proper treatment for a swift recovery.