Why Are My Dog’s Eyes Red?

If you have ever had eye issues, you know how uncomfortable it is, and your dog is no different. If you observe that your pup’s eyes are red, they could be experiencing severe itchiness or pain.

Your dog’s eyes could be red for many reasons, which could be anything from pink eye to glaucoma. It could also be a sign of environmental allergies or an injury caused by trauma.    

Getting your dog to the vet is essential, as early diagnosis and treatment may save their eyesight. Check out this article to know why your dog’s eyes are red.

Bulldog lurking with red eyes

Health Issues That Cause Red Eyes in Dogs Include:

If your dog has red eyes, you should not ignore the situation. Your pup’s eye health is at stake, and you do not want to overlook something that could turn into a serious issue. You need to know the symptoms of various eye conditions if you are going to help your dog. There are several explanations why your dog could have red eyes:


Conjunctivitis (Pink Eye)

Pink eye is common in dogs. It could be triggered by a viral or bacterial infection, allergies, or if your pup has an injury that gets infected. When a dog’s eyes are healthy and free of conjunctivitis, the eyelids are a pale pink color that is not so easy to see. The inflammation that is correlated with pink eye is what renders the membranes visible.

Pink eye presents as inflammation that coats the eye and the lining of the eyelids. Typically, only one eye is affected, but it could also be in both eyes. Dogs can have pink eye due to an underlying reason, such as infectious illness or a chronic eye condition. Pink eye comes with many symptoms:

  • Redness
  • Swollen or irritated eyelid
  • Mucus-like discharge
  • Watery eyes
  • Pawing at the eye
  • Squinting
  • Eyelids sticking together
  • Keeping eye closed
  • Cloudy cornea


Pink eye can seriously harm the eye if the condition is not treated quickly. Pink eye can also present with other symptoms, such as coughing, sneezing, and nasal discharge.

Corneal Inflammation (Keratitis) & Ulcers

The cornea of a dog’s eye is typically clear. However, if your pup has keratitis, it changes color. This change is because the surface of the eye becomes irritated. When inflammation is present, the eye becomes blurry. The eye develops a brownish coloring, and you can no longer see through it. It is the way that the eye protects itself.

The most common cause of a corneal ulcer in a dog is trauma to the eye. There are some symptoms you  to watch out for:

  • Cloudy eye
  • Discharge
  • Visible blood vessels in the cornea
  • Mucus-like discharge
  • Watery eyes and excessive blinking (if there are ulcers present)
  • Inflammation of the eye
  • Dry-eye


There are different types of keratitis. Your vet will be proficient in diagnosing which type your pup has. Many factors can cause non-ulcerative keratitis. Some include trauma to the eye, an eye infection, inability to close the eyes when sleeping, and glaucoma.

Dry Eyes

When your dog has dry eye, they cannot make sufficient tears to keep the eye lubricated—a thick layer of discharge forms in the eyes. The eyelid rubs against the cornea, which makes it appear cloudy. A dry eye can result from a bacterial infection due to the eye not being able to flush out the dirt and bacteria that it encounters. There are several symptoms of dry eye in dogs:

  • Thick whitish to yellow mucus-like discharge
  • Cloudy eye
  • Recurring eye infections
  • Excessive blinking
  • Redness, pain, or irritation of the eyeball
  • Holding the eyes shut


Your dog may also present with an abnormal number of blood vessels in the injured eye. In most cases, dry eye in dogs results from immune system dysfunction.

Dog Allergies

Dogs can get red-eye from breathing in environmental allergies like pollen, dust, or mold. Dogs with allergies can also present with problems related to their skin or intestinal tract. Dogs who develop skin-based allergy symptoms are more likely to suffer from allergic conjunctivitis than dogs who have no history of allergies.

Many dogs get seasonal allergies the same way humans do. There are several key symptoms you should watch for if your pup has allergies:

  • Tears or watery discharge
  • Red or irritated skin
  • Excessive itching or scratching
  • Itchy eyes
  • Hair loss
  • Sneezing
  • Coughing
  • Runny discharge from the nose


In addition to having environmental allergies, your dog could also have red eyes if they are allergic to certain foods. These foods include protein, corn, wheat, soy, and dairy.

Dog with allergies

Cherry Eye

Cherry eye is the general term for your dog having a prolapse of the third eyelid. The third eyelid acts as additional protection for the eye. The third eyelid also contains a special gland that generates a considerable portion of the eye’s protective film. If the gland pops out, it is called “cherry eye.” There are some symptoms:

  • Protruding third eyelid resembling a cherry pit
  • Red, itchy, swollen eye
  • Mucus like discharge from the eye
  • Inability to close eye
  • Dry eye

Typically, cherry eye is recognizable, even if no other symptoms are present.


Dogs get glaucoma when their eye fluid does not effectively drain, putting pressure on the eyes. It could be caused by debris or even scar tissue due to injury. Dogs can suffer from three different types of glaucoma. Congenital glaucoma is only seen in puppies 3 to 6 months old, and it is often seen with ocular abnormalities.

Certain breeds inherit primary glaucoma. It involves an interference with the outflow of fluid from the eye, which causes an increase in IOP. Secondary glaucoma occurs when there is another eye condition present. It could be anything from tumors in the eye to uveitis. Some of the indicators of glaucoma in dogs are:

  • Slight difference in pupil size (early onset)
  • Eyelid openings do not match (early onset)
  • Squinting
  • Tearing
  • Swollen eye veins in the white of the eye
  • Slight eye enlargement
  • Dilated pupils that do not respond to direct light
  • Redness in the whites of the eye
  • Swelling or inflammation of the eye
  • Elevation of the third eyelid
  • Scratching or rubbing of the eye
  • Lack of energy or sleeping more
  • Avoidance of being touched near the eye
  • Lack of appetite
  • Increased watery discharge
  • Sudden vision impairment or blindness


It needs to be stressed that glaucoma can lead to blindness. Still, the early diagnosis will provide a better outcome. If you observe that there may be something unusual with your pup’s eyes, get them to the vet immediately.

An Injury Caused by Trauma

If your pup has recently suffered trauma to their eye, it may become infected and lead to a condition like pink eye. In some instances, it may be evident that the eye is injured. You may see a scratch on the eyeball, a damaged eyelid, or contusions around the eye. Your dog may be holding their eye closed or squinting.

An eye injury can lead to a serious eye condition. If you see any signs of trauma or damage to your dog’s eye, take them to the vet as soon as possible.

Dog with pink eye



If your pup displays any or all of the symptoms above and has red or bloodshot eyes, make sure you get them to the vet right away. Early diagnosis and treatment are vital to prevent any further damage.




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