Dog Eye Infection: Signs, Causes and What to Do

What an eye infection usually means

Red, runny eyes in dogs are commonly grouped as conjunctivitis, inflammation of the pink tissue lining the eyelids. VCA Animal Hospitals explains that bacteria and viruses can be responsible, but so can allergies, dry eye, blocked tear ducts, eyelid or eyelash problems, smoke, trauma and foreign material. In many dogs the bacteria are a secondary problem on top of one of those.

Corneal scratches and ulcers are another cause that can look like an infection at first. The AKC lists rubbing, sand, thorns, sticks and shampoo in the eye as common ways the surface gets damaged. This is why a discharging eye should not be treated as a simple infection at home. The right fix depends entirely on the cause, and only an eye exam can tell them apart.

Signs to watch for

The AKC lists excess tearing, squinting or blinking, a third eyelid that shows, yellow-green discharge, pawing at the eye, keeping it closed and light sensitivity. VCA adds red, swollen tissue around the eyes and cloudy, yellow or greenish discharge. Both eyes may be affected, or only one.

The pattern gives a clue, though not an answer. The AKC says that when only one eye is affected, infection or injury is more likely, while allergies usually involve both eyes. Thick yellow or green mucus can point to dry eye, where too few tears let bacteria build up. Cloudiness, a visible change on the surface of the eye or obvious pain are worth treating as more serious, so compare with our pages on red eyes in dogs and dog eye boogers.

When to call your vet, and when it is urgent

Call your vet today if your dog is squinting, holding the eye shut, pawing at it, or has thick colored discharge, a cloudy surface or a swollen eyelid. The AKC says an infection that is not clearing within about 24 hours needs veterinary care, a suspected allergic reaction should be seen in the first day because rubbing causes more damage, and a corneal scratch needs prompt attention.

Go to an emergency vet right away after any injury to the eye, if the eye looks bulging or out of position, if there is bleeding, or if your dog seems in severe pain. Eyes can deteriorate quickly, and an ulcer left alone can damage vision. Phone ahead, and have someone gently stop your dog from rubbing the eye on the way.

What you can do at home, and what to avoid

The AKC suggests that before you reach the vet you can gently flush the eye with a cotton ball soaked in lukewarm water, wiping from the inner corner outward and using a clean piece each time. Keep your dog from pawing or rubbing the eye. If your vet advises a cone while it heals, that usually helps. Our dog cone range is there if you need one.

Do not use human eye drops, and do not use leftover drops from an earlier problem. The AKC warns these may be inappropriate and could worsen the infection, and VCA says medication that helped before may not help, or may be harmful, this time. Avoid smoke, dust and sprays near your dog's face while the eye is sore, and do not let your dog hang its head out of a moving car window.

How a vet finds the cause

Your vet will start with the history and a full eye exam, often with an ophthalmoscope. VCA lists common tests: a Schirmer test of tear production, a pressure measurement to rule out glaucoma or inflammation inside the eye, and fluorescein dye to spot corneal ulcers. Cultures, cytology, tear duct flushing or allergy testing may be added.

Treatment follows the cause. VCA says bacterial cases may get topical antibiotic ointments or drops, dry eye needs tear-stimulating medication and lubricants, and eyelid or eyelash abnormalities may need surgery. Ulcers, glaucoma or inflammation inside the eye can require several medications. Most simple cases have a very good outlook, while dry eye and immune-related conditions may need lifelong therapy.

Keeping your dog's eyes healthy

Prevention is mostly about avoiding injury and irritation. The AKC suggests trimming bushes around your yard, keeping the hair around the eyes trimmed and clean, and not letting your dog ride with its head out of the window. Rinse out dust after windy walks, and ask your vet before using any drops, even artificial tears.

Learn your dog's normal. A little clear tearing or a dry crust in the morning is common in many dogs, but a change in color, amount or comfort is a reason to call. Dogs with prominent eyes or droopy lids need extra attention, because they pick up irritation more easily. If you notice swelling or a pink mass in the corner, see our page on cherry eye in dogs.

This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.