8 Potential Causes of Bloodshot Eyes in Dogs
Bloodshot eyes in dogs may or may not be cause for concern. There are numerous reasons why your dog’s eyes are red. For example, some naturally have red in their eyes.4
Here are some other common causes of bloodshot eyes in dogs, including their symptoms, potential treatment options, and when to see a veterinarian:
1. Corneal ulceration
Corneal ulcers happen if your dog gets a scratch on their eye or a foreign object stuck in it. As a result, the cornea can appear red.1
Other Symptoms
- Squinting with one or both eyes
- Discharge from the tear glands in the inner corner of the eyes
- Scratching or “pawing” at the eyes
- Excessive blinking
Treatment
To treat a corneal ulcer, your vet might prescribe antibiotic eye drops to prevent infections from developing in your dog’s eye.
2. Eye trauma
Eye injuries are common in dogs, especially if they get a foreign body stuck in their eye while playing.
For example, if your dog fights with another dog or animal, that leads to an eye scratch or injury, it might appear red.
Other Symptoms
- Bleeding
- Discharge
- Watery eyes
- Bacterial infection from wounds
- Squinting
- Swelling
- Sensitivity to bright light
Treatment
The best treatment for an eye injury depends on the type. Your dog will need a proper diagnosis from a veterinary ophthalmologist.
In severe cases of physical trauma, your dog might need surgical treatment or stitches. The vet may prescribe pain medications.
3. Conjunctivitis
Conjunctivitis (pink eye) can occur in people and dogs. A viral or bacterial infection causes this condition and leads to your dog’s eyes reddening.2,3,8
Other Symptoms
- Itchiness
- Swelling
- Watery discharge
Treatment
You can usually treat conjunctivitis with eye drops. Eye drops can also treat other symptoms of pink eye beyond eye redness. For example, they help lubricate your dog’s eyes and prevent pain and itchiness.
4. Environmental irritants
Certain environmental irritants can affect your dog’s eyes. These include dust or other allergens in the air.2
Other Symptoms
- Itchy eyes
- Scratching or “pawing” at the eyes
- Watery eyes
- Dry eye
- Inflammation
- Swelling
Treatment
If seasonal allergies are causing your dog to have bloodshot eyes, ointments or oral medications might help. In the case of seasonal allergies, bloodshot eyes and other symptoms typically subside on their own.
Allergy testing, such as blood tests, can help determine or rule out specific food and pet care product allergies.
5. Infection
Redness is a common symptom if your dog’s eye has an infection. If left untreated, the condition and symptoms can worsen and become painful.
Other Symptoms
- Enlarged blood vessels
- Watery discharge
- Itchiness
- Pain
Treatment
If your dog has an eye infection, the vet may prescribe an ointment or medication to kill the bacteria causing the infection.
6. Eyelid problems
Eyelid problems can also cause red eyes in dogs. It can happen if the eyelids fold out (ectropion) or in (entropion). When they fold out, your dog’s eyes are left unprotected. When they fold in, the eyelashes can irritate the eye's surface.
Other Symptoms
- Folded eyelids
- Itching
- Dry eye
Treatment
Many long-haired and flat-faced breeds have trouble with their eyelids due to fur and skin obstructing their vision. Keeping your dog’s eyes healthy by maintaining proper pet care is important.5,7
7. Glaucoma
Glaucoma is a common condition that affects many older dogs. It can lead to red eyes and other symptoms.6
Other Symptoms
- Difficulty seeing
- Cloudy eyes
- Dry eyes
Treatment
Glaucoma in dogs can get worse with age. Oral or injected medications can help treat glaucoma.
8. Dry eye syndrome
Dry eye syndrome is a health condition that can affect people and dogs. It happens when the eyes do not produce enough moisture and feel very dry, causing redness.2
Some breeds of dogs are more prone to dry eye syndrome than others.
Other Symptoms
- Dry eyes
- Difficulty seeing
Treatment
If your dog suffers from dry eye syndrome, your vet might prescribe artificial tears to help induce tear production and lubricate their eyes.
When to See a Veterinarian
Talk to your veterinarian if your dog’s red eyes seem to come on out of nowhere or get worse over time. Call the veterinarian if your dog’s eyes do not improve with treatment.
While a dog’s red eyes aren’t typically a cause for concern, they can be due to underlying health conditions.
Summary
The recovery timeline depends on why your dog’s eyes are red. The outlook is generally positive since most cases resolve independently or with eye drops. However, if a more severe condition like glaucoma is the cause, your dog might require lifelong treatment.
If you’re concerned, talk to your veterinarian so they can determine a proper treatment plan for your dog.
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