If you’re wondering, “Why are my dog’s eyes red?” it’s important to be clear on what exactly “red eyes” means in dogs. When a pet parent says their dog’s eyes are red, they usually mean one of several things:

A dog’s eyes may become red for many reasons, ranging from episcleral injection to hyphema or periocular irritation. Redness of the eye can indicate mild irritation, severe ocular disease (e.g., glaucoma, uveitis, infection), or even systemic issues (e.g., blood clotting disorders). If your pet’s eye redness is new, it’s best to have it checked by a veterinarian. 

Here, we’ll talk about common causes of eye redness, what to do if you’re noticing eye redness, and when to see your pet’s veterinarian.

Dog Eye Irritation Causes: Why Are My Dog’s Eyes Red?

Eye issues can progress quickly and may affect your dog’s vision. Your veterinarian can show you what to look for at home to ensure the condition is improving. Some reasons your dog’s eyes may become red or irritated include:

Episcleral injection

The white of the eye is called the sclera. When blood vessels in the sclera become enlarged, you can see redness and prominent vessels in the outer part of the eye.

Conjunctival redness or hyperemia

The conjunctiva lines the inside of the eyelids and the sclera near the front of the eye. If your dog has conjunctival hyperemia, you may notice redness or swelling of the eyelids and/or a reddish tint to the whites of the eyes. Vessels are usually visible in the white of the eye, but are less pronounced than they are with episcleral injection.

Hyphema

Hyphema refers to the pooling of blood within the front of the eye.

Subconjunctival hemorrhage

 If a large section or the entirety of the white of the eye appears red without visible vessels, this is usually a subconjunctival hemorrhage, meaning bleeding beneath the conjunctiva.

Periocular irritation

When a dog has periocular irritation, they have inflammation around (“peri”) the eye (“ocular”). The eye itself may appear normal, or it may be irritated if the dog is rubbing or pawing at the eye, but it’s the skin around the eyes that is usually red and inflamed.

In corneal injuries, the corneal surface sometimes develops new blood vessels (i.e., corneal neovascularization). Generally, pet parents don’t note this as a “red eye,” but they may notice the red vessels crossing the eye. Corneal neovascularization can occur in conjunction with other types of red eye, depending on the cause.

Why Are My Dog’s Eyes Red?

Dog eye irritation causes range from mild to severe. Here, we’ll cover common causes of redness in dog eyes.

Allergic/Environmental Irritants: Just as allergens and environmental irritants can irritate our eyes, our dogs can develop conjunctival inflammation and redness from pollen, smoke, and dust.

Foreign Body/Trauma: Foreign objects, such as grass seeds or twigs, can cause trauma to the surface of the eye, most commonly resulting in scratches or ulcers on the cornea. Redness will usually be sudden, and the dog may struggle to keep their eye open.

Infectious Conjunctivitis: Certain bacterial and viral infections can cause swelling and inflammation of the conjunctiva. You may also notice discharge from the eye, which is usually clear with viral infections and green, yellow, or white with bacterial infections. In some cases, the dog may also have other respiratory symptoms, such as nasal discharge, sneezing, or coughing.

Dry Eye (Keratoconjunctivitis Sicca): Dry eye in dogs is usually caused by an autoimmune attack of the tear-producing structures in the eye. Dogs with KCS have reduced tear production, leading to irritation and redness in the eyes. You may notice discoloration or scarring on the cornea, and the dog will have thick discharge from the eye.

Glaucoma/Elevated IOP: If the pressure in your dog’s eyes (i.e., intraocular pressure or IOP) is high, this is called glaucoma. Dogs with glaucoma will have an episcleral injection, causing eye redness, pain in the eye, and vision changes. The eye may appear to bulge. Glaucoma requires urgent care or can result in permanent vision loss.

Uveitis (Anterior): Uveitis is inflammation inside the eye. With anterior uveitis, the inflammation occurs in the front of the eye, including the iris (colored ring in the eye). Uveitis is painful, and the dog may squint or paw at the eye, and an episcleral injection will cause redness. In some cases, the dog is sensitive to light (i.e., photophobia). Uveitis in dogs can be caused by eye changes, such as cataracts or glaucoma, or by systemic conditions, such as fungal infections or tick-borne diseases.

Corneal Ulceration or Keratitis: Injury or inflammation of the cornea causes redness, squinting, and discharge. You may see discoloration of the surface of the eye or an injury to the surface of the eye. Injury and inflammation of the cornea can occur due to trauma, infection, dry eye, and other causes. Without prompt treatment, the condition can cause serious eye problems, such as glaucoma or uveitis, leading to vision loss.  

Eyelid/Third-Eyelid Disorders: Disorders of the eyelids, including the upper, lower, and third eyelid, can result in corneal ulceration or inflammation. Entropion is when the eyelids roll in, causing the lashes to rub on the cornea. With ectropion, the eyelids are rolled out, exposing the conjunctiva and increasing air exposure. A prolapsed gland of the third eyelid (cherry eye) can also lead to eye inflammation. With cherry eye, you may notice a reddish mass at the inner corner of the eye.

Breed-specific Predispositions: Some breeds are predisposed to eye conditions or have facial conformation that affects their eye health. For example, some brachycephalic (flat-faced) breeds have large eyes and flat faces, which affects the ability of tears to drain from their eyes. This can result in inflammation around the eye. Some breeds, like Cocker Spaniels, are prone to glaucoma.

Systemic Disease Indicators: Some systemic health issues can cause redness in the eye. These include hypertension, autoimmune conditions (like uveodermatologic syndrome), tick-borne diseases (like Lyme or ehrlichiosis), blood-clotting disorders, and cancer.

In some cases, your dog’s red eyes may have more than one cause. A veterinary evaluation is the best way to get to the root cause of a dog’s red eyes.

When to Visit the Vet

When you’re wondering, “Why are my dog’s eyes red?” if it is the first instance of red eye for your dog, it’s always a good idea to get them checked out by a veterinarian. Signs that your pet needs to be seen include:

  • Acute onset of symptoms without a known allergic or environmental trigger
  • Evidence of pain, including squinting, light sensitivity, excessive blinking, pawing at the eye, rubbing the eye on the floor or against objects
  • Cloudy cornea, discolored cornea, bluish appearance to the eye, or new vessels visible on the cornea
  • Vision changes
  • Discharge from the eye, especially if thick, yellow, or green
  • Bulging appearance to the eye
  • Visible blood in or around the eye
  • Abnormal pupil size or differences in pupil size between the two eyes
  • Recent history of trauma

There are certain questions you’ll want to ask yourself, which will also be helpful for your veterinarian in determining the cause, if need be:

  • How quickly did symptoms start?
  • Is the condition affecting one eye or both eyes?
  • Is discharge present, and, if so, what type is it?
  • Is your dog showing any signs of pain?
  • Is there any blood present around or within the eye?
  • Are you noticing changes to your dog’s vision, including in the daylight or in the dark?
  • Does your dog have a prior history of eye redness?
  • What breed predispositions does your dog have?

At-home observation may be acceptable if:

  • You have had your dog examined for red eyes before and have discussed at-home monitoring with your veterinarian
  • Redness is mild, and your dog has no pain or discharge
  • Your dog was recently exposed to a known irritant, like pollen
  • The condition has been present for a short time (less than 24 hours) and is improving

If no improvement is seen within 24 to 48 hours despite your at-home supportive care, or if symptoms are worsening, your pet should be seen by a veterinarian.

At-Home Supportive Care for Mild Eye Irritation

If this is a case in which at-home supportive care is acceptable, consider the following tips.

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  1. Medications: Do not use topical medications like steroids or antibiotics unless you were directed to do so by a veterinarian. If given inappropriately, medications can worsen your pet’s eye condition.
  1. Soothing eye washes: Use vet-approved, soothing eye washes like TropiClean HomeVet Soothing Eye Wash to flush or rinse the ocular surface after known irritant exposure, such as pollen or debris. TropiClean HomeVet Soothing Eye Wash, a sterile solution used to flush irritants from the eyes, can help soothe mild irritation caused by wind, dust, pollen, or other debris. Pet parents should apply the product as directed by their veterinarian or on the product label. If the dog responds painfully to the eye wash, stop use and contact your veterinarian. Remember only to use this product if your veterinarian has ruled out serious ocular health issues.
Try HomeVet Soothing Eye Wash
  1. Use gentle wipes: If there is discharge around your dog’s eyes, you can use gentle dog-safe eye wipes or unscented baby wipes to help clean the area. This may help prevent infection of the skin around the eye.
  1. Environmental adjustments: If your dog’s eyes are sensitive to environmental irritants, you can take steps to reduce their exposure. Avoid smoky or dusty rooms, and do not smoke in the house. Consider helping your dog adjust to wearing protective eyewear on windy or dusty days. Avoid using air fresheners and harsh chemical cleaners in your home. Change air filters regularly and consider purchasing air purifiers. Keeping your windows closed can also help reduce pollen exposure.

Actionable Guidance

“Why are my dog’s eyes red around the outside?” This is a common concern among pet parents. Because red eyes in dogs can signal a wide range of causes from benign to urgent, it’s important for pet parents to know when their pet may need help. 

While at-home supportive care is appropriate for mild, low-risk cases, veterinary triage and assurance that there are no red flags must be completed before relying on at-home care. Pet parents should familiarize themselves with their dog’s “normal” and the warning signs, such as pain, swelling, discharge, or vision changes.

TropiClean HomeVet Soothing Eye Wash is a convenient, safe product for flushing debris from the eyes and soothing mild irritation. Still, it shouldn’t be used as a substitute treatment for serious ocular disease. This and other supportive products can be used responsibly with veterinary guidance.

Photo by Jacob Narkiewicz on Unsplash