Red eye in the dog - What causes it and what can be done about it?

Red eye in the dog - What causes it and what can be done about it?

Health & Safety

Red eye or pink eye is the term used for a condition in which the mucous membranes of the eyes of the dog appear pink, red or inflamed, or otherwise look sore and uncomfortable. It is relatively common within our canine companions, but can be caused by a variety of different things, running from the minor to the more serious.

In this article, we will look into red eye in the dog in more detail, plus cover what causes it, and what can be done to resolve the problem. Read on to learn more.

What causes red eye in the dog?

The potential reasons for red eye in the dog can be very varied, and in some breeds with protruding eyes such as the pug and other brachycephalic breeds, their prominent eyes make them much more likely to sustain damage to their eyes or pick up debris that can irritate the eyes than other breeds. Some of the other potential reasons for red eye in either one or both eyes can include:

  • Injuries to the eye itself, such as if another dog or a cat has scratched the eye.
  • Allergies that lead to inflammation and irritation of the eye tissue.
  • A foreign body such as a grass seed trapped in the eye.
  • Conjunctivitis.
  • Entropion or distichiasis.
  • Bacterial, fungal or viral infections of the eyes.
  • Keratoconjunctivitis sicca, also known as “dry eye.”
  • Glaucoma.
  • Some forms of cancer.

Narrowing down the problem

If your dog had one good eye and one sore or inflamed eye, the issue is most likely caused by a trauma to that eye, such as if they have been scratched by the cat, or have picked up a grass seed or other tiny piece of debris in their eye. This will usually also be accompanied by squinting, and possibly scratching at the eye, you should get your vet to look at their eye as soon as possible.

If both eyes are affected, the condition can probably be narrowed down to a problem that is apt to affect both eyes at once, such as dry eye, allergies or an infection.

Either way, it is wise to take your dog along to the vet for a full eye check-up, which will usually involve examination with an ophthalmoscope as well as a range of other tests depending on what is found and what your vet suspects the problem to be.

Can red eye in the dog be treated?

What can be done about the underlying problem and associated redness will largely depend again on the cause of the problem. Some of the most common problems of the eyes can be treated or managed as follows, in conjunction with your vet:


Conjunctivitis can usually be resolved relatively simply with an antibiotic eye cream, and while conjunctivitis is mucky, unsightly and irritating for your dog, it is actually a minor problem that can usually be cured without a lot of difficulty.

Conformation problems

Conditions such as entropion (in which the lids of the eyes turn inwards and rub on the cornea) or distichiasis (in which the eyelashes grow a second row, which rub on the eye) can be problematic and painful for the dog in the long term, and while infections and problems can be treated on a day to day basis, such conformation flaws will often require surgery to correct and prevent future problems.

Trauma to the eye

Damage to the eye itself, such as if the eyeball has been scratched by a cat, can generally be treated with a topical antibiotic cream, assuming that the damage is only superficial and not severe. In the case of more serious injuries, the lids of the eye may need to be stitched closed temporarily, in order to allow the eye to heal.

Eye infections

Infections of the eyes can be caused by bacteria, viruses or fungal causes, and treating the red eye will rely upon finding the right medications to resolve the issue with.

Foreign bodies in the eye

Grass seeds and other small pieces of debris can lodge in the eye and be very irritating for your dog, which is likely to make them scratch at and otherwise bother their eye, potentially making the problem worse. Finding the object and removing it or flushing it out with a saline solution, plus antibiotics if the debris has caused an infection, will normally promote healing.


A diagnosis of cancer of the eye is understandably worrying and potentially serious, but many forms of eye cancers can be treated if they are caught early enough. Some common eye tumours include mast cell tumours and lymphosarcoma, and your vet will need to biopsy the tumour itself to establish what it is, and work out how best to proceed.

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