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Dog with a red eye

What causes red eyes in dogs?

Red eyes are a worrying sight for pet parents, but not all cases are alike. Eye redness in dogs might mean an eye infection or disease, an allergy, or simply an irritant or object caught within the eye. Some eye problems in pups involve visible symptoms like excessive tears and rubbing or pawing at the eyes. However, eye redness can also be a sign of more serious underlying issues. Here are nine common causes of bloodshot or red eyes in dogs, and ways to recognize them.

1. Eye injury

Much like humans, dogs’ eyes are sensitive and prone to trauma. If you notice a wound or scratch accompanying your dog’s red eyes, an injury may be to blame. A visit to the vet can help confirm these suspicions.

2. Irritation from foreign objects

We all know the pain (and annoyance) of having something stuck in your eye, and dogs are no different. Objects like dirt, grass, or rocks can find their way into your dog’s eyes and cause redness until flushed out or removed.

3. Dry eyes (KCS)

Some dogs don’t produce enough tears to keep their eyes lubricated.  The medical term for “dry eye” in dogs is keratoconjunctivitis sicca (KCS). This can cause redness accompanied by excessive blinking, squinting, thick eye discharge, or infection. A vet can prescribe medication to help stimulate tear production.

4. Allergies

Dog allergies come in many forms, with various symptoms. If you notice red, runny eyes and excessive itching, especially in spring or summer, your dog may have seasonal allergies. Pollen, grass, plants, and mites are common seasonal allergy culprits.

5. Conjunctivitis

Also called pink eye, conjunctivitis is an inflammation of the conjunctiva i.e. the tissue covering the eye and inside of the eyelids. Symptoms include redness, inflammation of the eyelid and/or cornea, and discharge of mucus. Pink eye in dogs can typically be easily diagnosed and treated by a vet.

👉 Conjunctivitis is often itself a symptom of other eye conditions as well.

6. Glaucoma

Glaucoma is caused by fluid buildup, leading to increased pressure in the eyes. Unlike in humans, glaucoma in dogs progresses rapidly and can lead to blindness if unaddressed. Signs include redness, dilated or slow-moving pupils, and cloudy eyes. Suspected glaucoma cases should be referred to a vet or veterinary ophthalmologist (animal eye doctor) as soon as possible.

7. Cherry eye

Dogs have a third eyelid, called a nictitating membrane, to protect the eyeballs. Cherry eye occurs when the gland of this eyelid pops out or prolapses, causing a swollen red mass. Certain breeds, like American bulldogs, beagles, and cocker spaniels are genetically more prone to cherry eye. While many cases resolve on their own, some require surgery to correct.

8. Corneal ulcers

Most corneal ulcers in dogs are caused by injuries or foreign objects in the eyes. The resulting sores, or ulcers, can affect the surface of the cornea or deeper into the eye.  Pain, swelling, and redness are common symptoms of corneal ulcers. A vet visit is recommended in these cases for proper diagnosis, which involves staining the eye with a fluorescent dye. Treatment options for ulcers include eye drops or surgery in more severe cases.

9. Uveitis

Uveitis is an inflammation of the uvea, which includes the iris (colored part of the eye), ciliary body, and choroid. Symptoms include excess redness, tearing, blinking, and avoidance of bright lights, and can be similar to signs of glaucoma. A vet may perform tests to measure eye pressure to help diagnose uveitis.

Diagnosing the cause of red eyes

With some common reasons, like an injury, the cause of redness in your dog’s eyes may be pretty clear. With others like allergies or optical illnesses, you may need the help of a veterinarian. A vet or veterinary specialist can perform an ophthalmic exam of your dog’s eye to get to the root of the problem. There are also allergy tests for dogs to help determine causes of irritation. Depending on the testing outcomes, a vet may prescribe oral antibiotics or topical ointments or eyedrops to address your dog’s symptoms.

Why dog’s eyes are sensitive

In terms of design and function, dogs’ eyes are extremely similar to our human eyes. As a result, dogs are likely to have many of the same eye conditions as us people, especially age-related changes. However, there are a few factors, whether genetic or lifestyle-related, which may affect a dog’s likelihood to experience eye-related issues.

Dog eye anatomy

Anatomy of a dog’s eye highlighting areas commonly affected by eye conditions. Source:

When it comes to breeds, brachycephalic or flat-faced dogs like pugs, American bulldogs, and shih tzus are more prone to corneal exposure (damage to the cornea due to dryness). This can lead to greater risk of corneal dystrophy or ulcers, leading to vision loss if untreated.

Similarly, dogs with long hair around their eyes, like poodles or Maltese, are often at greater risk of eye irritation or infection. As with humans, no two dogs are alike, so it’s up to pet parents to monitor their dogs’ eyes for any noticeable changes which may require treatment.

How to treat your dog’s irrritated eyes at home

While some dog eye conditions require professional medical treatment, certain cases of red eyes can be managed at home. For example, if seasonal allergies to dust or pollen are causing the redness, a vet may recommend one of these effective at-home remedies to alleviate eye redness:

  • Non-medicated sterile saline rinses. The Nutri-Vet Eye Rinse will help flush the eye of irritants and stave off bacteria and infections with ingredients like boric acid.
  • Eye wipes. These wipes from Miracle Care are an easy way to keep the area around your dog’s eyes clean and free of dirt and secretions. A warm, damp washcloth can also work in a pinch.
  • Allergy supplements. Zesty Paws Aller-Immune Bites contains vet-approved ingredients like Colostrum and Astragalus Root. These act as anti-inflammatories and support the immune and digestive systems.

Tips to keep your doggie’s eyes healthy

Dogs’ eyes are vulnerable to a wide variety of injuries and diseases. It’s up to us as pet parents to always maintain our pet’s eye health and hygiene, and monitor any changes. Discovering an eye condition early on can go a long way toward treating the problem before it leads to serious conditions like blindness.

Keep eyes clean, clear, and free of yucky discharge You should always clean your dogs’ eyes with every bath, but a quick wipe down every few days is a good idea. Also, keep the hair around your pooches’ eyes trimmed to avoid irritation.

👉 Occasional eye discharge or drainage is normal, but if you start to notice it happening more you should consult a vet.

Watch for changes — You should recognize what your dog’s eyes look like when healthy. A noticeable change like excessive redness or tearing can be a sign of an irritant or illness and should prompt a vet visit.   

Don’t self-diagnose — Eye problems in dogs can be really complex, so it’s best to err on the side of caution. Before attempting to treat eye redness at home, check with your pup’s vet to ensure the problem isn’t a sign of something more serious.

Avoid eye trauma — This may be easier said than done, but there are some steps you can take. For example, if your pup likes to ride with their head out the window in the car, consider doggles (dog goggles) to minimize any foreign objects entering the eyes.

Frequently asked questions about red eyes in dogs

Are red eyes normal in dogs?

Bloodshot or red eyes aren’t generally normal in healthy dogs.

Why are my dogs eyes red all of a sudden?

Red eyes can be caused by a variety of factors, including injuries, foreign objects, allergies, and optical diseases like conjunctivitis or glaucoma.

Why are my dog’s eyes red after grooming?

Irritation to the area around the eyes during a grooming session may cause redness. Environmental or chemical irritants present at the groomer may also be at fault.

What if it’s red around my dog’s eyelids?

Red eyelids can signal a number of issues including cherry eye and entropion. In these cases, a vet visit is recommended to ensure a proper diagnosis.

Can I use human eye drops for my dog?

We never advise to use human eye drops, or any optical medication, without consulting a veterinary or specialist first.

When should I see a vet about my dog’s red eyes?

Some dog eye issues can progress rapidly, so it’s better to be safe than sorry. Any noticeable changes in your dog’s eye color or redness should prompt a visit to the vet sooner rather than later.