There are many causes of eye infections in dogs. If your canine pal is exhibiting discomfort, redness, or even sensitivity to light, it's a good idea to consult your veterinarian. Left untreated, eye infections can spread or lead to vision loss. These are some of the basic types of infection, including:
- Conjunctivitis, also known as pink eye or red eye, is an inflammation of the conjunctiva, a thin mucous membrane covering the front of the eye and lining the inner surface of the eyelid.
- Inflammation of the cornea
- Uveitis, which is inflammation in the interior portion of the eye, consisting of the iris, ciliary body (a circular structure just behind the iris), and the choroid (tissues behind the iris)
- Abnormalities in the eyelids and tear glands
Causes of Dog Eye Infections
As in humans, there are many causes of dog eye infections. These include:
- Viruses, such as distemper, herpes, hepatitis, canine influenza
- Bacteria, such as canine brucellosis, leptospirosis, and such tick-borne diseases as canine ehrlichiosis, and Lyme disease
- Irritants, like smoke or shampoo
- Foreign matter, like dirt, grass seed, or a dog's own hair
- Scratch or a cut on the cornea
Other problems can provoke symptoms that look like an eye infection, including:
- Tear duct problems, more common in Cocker Spaniels and Poodles
- Dry eye
- Vitamin deficiency
- Eyelid abnormalities, including entropion (the eyelid rolls in and irritates the surface of the eyeball) and cherry eye (when the dog's third eyelid protrudes)
Symptoms of Dog Eye Infections
- Watery or thick, smelly discharge
- Holding eye closed
- Light sensitivity
- Pawing at the eye
How Veterinarians Diagnose a Dog Eye Infection
According to the American College of Veterinary Ophthalmologists, eye exams for dogs are very similar to those for humans. "The exception is it's very hard to get veterinary patients to read an eye chart," the ACVO noted in a fact sheet. A dog's eye exam may consist of the following tests:
- Schirmer Tear Test—measures the eye's tear production and will be conducted when there is redness or discharge.
- Visual examination with a focal light source of the eyelids and front half of the eye
- Intraocular pressure (IOP), measured with an instrument called a tonometer, to look for signs of glaucoma
- Dilation with special eye drops allow the vet to examine the back of the eye, including the condition of the optic nerve and retina and the reflectivity of the tapetum, a layer of tissue in the canine eye that reflects light and improves night vision.
- Corneal staining with a fluorescein dye that will reveal ulcers or other breaks in the surface of the cornea.
- Bacterial culture
- Allergy tests
Steps for Applying Your Dog's Eye Medication
Your vet will pinpoint the cause of your dog's eye discomfort and create a treatment plan. Sometimes this will involve treating an underlying condition, such as an allergy, autoimmune disease, or tumors. Issues related to the eyes alone may require both systemic (involving the whole body) and topical medications. In many cases, eyedrops or ointments are required. (Do not use over-the-counter eyedrops designed for humans, such as Visine.)
Preventing Dog Eye Infections
There are a few steps you can take to prevent eye infections in your dog:
- Avoid trauma to the eye or the introduction of foreign bodies. One good way to protect them is to close the window when you are driving. Dust, seeds, and other foreign bodies can fly into the eye on the wind.
- Trim hair around the eye so that it won't irritate the eyeball.
- Keep your dog's face clean.
- Protect the eyes with goggles designed for dogs.
Sources: Merck Veterinary Manual; VCA Hospitals; American College of Veterinary Ophthalmologists