Dog Eye Infections: Signs, Treatment and When to Worry

Signs of an Eye Infection in Dogs

• Yellow, green or thick mucus-like discharge^1,3
• Red eyes or eyelids, and swollen lids^1,3
• Squinting, blinking a lot, or holding the eye closed^1,3
• Pawing or rubbing at the eye¹
• Watery eyes, sensitivity to light, or the third eyelid showing¹

Yellow, green or heavy discharge is worth a vet visit.^1,8

Is It Really an Infection?

Several conditions look like an infection but need very different treatment:^1,3,2

• Corneal ulcer: a scratch or sore on the clear front of the eye, usually from an injury. It is painful, so dogs squint, and the eye may look cloudy. Ulcers can get worse quickly.^6,1 See eye ulcers in dogs.
• Dry eye (KCS): too few tears, which causes red eyes with thick, sticky discharge, usually in both eyes. It's common in Cavalier King Charles Spaniels, English Bulldogs, Lhasa Apsos, Pugs, Shih Tzus and West Highland White Terriers.⁹
• Allergies: red, watery, itchy eyes, often in both eyes, sometimes with itchy skin.^1,2
• Glaucoma: high pressure inside the eye, causing pain, redness, a cloudy cornea and a dilated pupil. It can cause permanent blindness quickly and is an emergency.^4,5
• Eyelid and lash problems such as inward-rolling lids (entropion) or extra lashes rubbing the eye, and foreign bodies such as grass seeds^3,1
• Cherry eye: a red lump in the inner corner of the eye. See cherry eye in dogs.

What Causes Eye Infections in Dogs?

Bacteria live on the surface of healthy dog eyes, and true infection usually happens when the eye's defenses are damaged, for example by an ulcer, dry eye or an eyelid problem.^2,1 Viruses such as canine distemper, canine herpesvirus and canine adenovirus can also cause eye inflammation, often along with other signs of illness; vaccination protects against distemper and adenovirus.^3,10,11 Infection can also follow an injury or spread from the eyelids.¹

How Vets Diagnose Eye Problems

• Fluorescein stain: an orange dye that turns green where the cornea is scratched or ulcerated^6,12
• Schirmer tear test: a small paper strip that measures tear production, to check for dry eye^9,3
• Eye pressure (tonometry) to check for glaucoma^3,1
• Sometimes a culture, cytology or allergy testing^3,8

How Dog Eye Infections Are Treated

• Antibiotic drops or ointment for bacterial infection, and to protect an ulcer while it heals. These need a prescription.^3,6,13
• Treating the underlying cause: tear-stimulating medicine (cyclosporine or tacrolimus) for dry eye, allergy treatment, or surgery for eyelid and lash problems^3,9
• Anti-inflammatory drops, but only once the vet has confirmed there's no ulcer. Steroid drops, and some anti-inflammatory drops, can make an ulcer deepen and "melt."^12,6
• A cone to stop rubbing^1,6

Most simple cases improve within days. Recheck as your vet advises, and call right away if the eye looks worse or more painful.^6,14

Home Care and What to Avoid

There's no safe way to cure a true eye infection at home, but these steps help while you arrange a vet visit:^1,15

• Gently wipe away discharge with a cotton ball or soft cloth soaked in lukewarm water, wiping away from the eye.^1,15
• Rinse with plain sterile saline eye wash, not contact lens solution.^15,16
• Use a cone if your dog is rubbing the eye.¹

Don't use:

• Human eye drops, especially redness-relief drops such as Visine. Their decongestant ingredients can be toxic to dogs, and swallowing even a small amount (for example, by chewing the bottle) can cause a dangerously slow heart rate and collapse. If your dog chews or swallows eye drops or nasal spray, call your vet or a pet poison hotline right away.¹⁷
• Leftover eye medicine from a past problem or another pet. Drops containing a steroid can make an ulcer much worse.^1,3,12
• Homemade eye rinses or remedies. Vets advise against them, because the wrong treatment can make some eye problems worse.^14,18

Antihistamines such as Benadryl don't treat infections and only help some allergy-related eye problems; ask your vet before giving any medicine.^1,14

Our guide to dog eye wash explains how to clean your dog's eyes safely.

Frequently Asked Questions

Can a dog's eye infection heal on its own?

Mild irritation sometimes settles, but a true infection usually needs prescription treatment, and the cause, such as an ulcer or dry eye, needs to be found. Don't wait if your dog is squinting or the eye is cloudy.

How can I treat my dog's eye infection at home?

You can gently clean away discharge with lukewarm water or sterile saline and use a cone to stop rubbing, but your dog needs a vet exam and, if there's an infection, prescription drops or ointment.

Can I use human eye drops on my dog?

No. Redness-relief drops such as Visine can be toxic to dogs, and other human drops may make the problem worse. Use only drops your vet prescribes.

Are there over-the-counter antibiotic eye drops for dogs?

Not in the US. Since June 2023, animal antibiotic products, including oxytetracycline products such as Terramycin eye ointment, need a prescription. Your dog needs an exam anyway, because a stain test shows whether there's an ulcer, which changes which drops are safe.

How do I know if my dog's eye problem is an emergency?

Squinting, a cloudy or bulging eye, sudden vision loss, a very red eye, or an injury all need a vet the same day.

Will Benadryl help my dog's eye infection?

No. Antihistamines don't treat infections. They may help some allergy-related eye problems, but ask your vet first.

Can a dog eye infection spread to people?

It's rare. Most causes of red eyes in dogs aren't contagious to people, but wash your hands after cleaning your dog's eyes or giving drops.