Dogs use their eyes for many tasks, like navigating the outdoors, chasing a ball during a game of fetch, and staring deeply into your eyes when it’s dinnertime. Therefore, when a dog’s eyes are red, it’s a serious problem.
Red eyes in dogs have many causes, which are discussed below. Regardless of the cause, eye redness warrants a trip to the veterinarian for prompt diagnosis and treatment.
Causes of Red Eyes
When we talk about red eyes, we’re referring to the blood vessels in the sclera, which is the white of the eye. In a healthy eye, these blood vessels are barely visible. However, when there’s a problem in the inner or outer parts of the eye, these blood vessels engorge with blood, making the eyes look red.
When a dog’s eyes are red, there are often other symptoms, such as excessive blinking and squinting, to indicate a problem.
Here are some common causes of red eyes in dogs.
Allergies Dog allergies, particularly environmental allergies, irritate the eyes and cause them to turn red. Common environmental allergens (substances that cause allergies) are dust and pollen. As in people, environmental allergies in dogs are typically seasonal but can be year-round.
Corneal ulcers The cornea is the clear, round covering over the eye. Sometimes, the cornea can develop an ulcer from causes like infections or trauma. With dog eye ulcers, new blood vessels form on the cornea to try to heal the ulcer. These new blood vessels make the eye look red. Corneal ulcers can be superficial but may become deep if left untreated. Deep corneal ulcers can ultimately result in blindness.
Conjunctivitis Conjunctivitis, commonly known as “pink eye,” is inflammation of the conjunctiva, which lines the inner eyelids and sclera. It is commonly caused by an underlying systemic infection or eye disease. Conjunctivitis is contagious, so dogs in relatively close quarters, such as at dog parks or in doggie day cares, are prone to developing this condition. It causes conjunctival swelling and redness, making the eyes look red.
Glaucoma Glaucoma in dogs is elevated pressure in the eye, caused by impaired fluid drainage. This drainage problem is primary or secondary. Primary glaucoma is genetic, with certain breeds, such as Basset Hounds and Shar-Peis, being predisposed. Secondary glaucoma is due to an eye disease or injury, such as a tumor. If left untreated, glaucoma damages the retina and optic nerve, leading to blindness.
Keratoconjunctivitis sicca (KCS) KCS, or dry eye, is a common eye ailment in dogs. Some breeds, such as Bulldogs and Cocker Spaniels, are prone to KCS. It occurs when the tear glands do not produce enough tear film, causing corneal dryness. A dry cornea can become ulcerated. KCS is very painful and uncomfortable, necessitating prompt treatment.
Infections Viruses, such as canine distemper and herpes, commonly cause dog eye infections and eye redness. Certain bacterial infections, such as leptospirosis and kennel cough also cause eye redness in dogs. Vaccines are available to prevent these infections.
Trauma Isn’t it annoying when something gets stuck in your eye? Well, the same thing can happen to dogs. A foreign object, such as a small chip of wood, can cause major eye irritation and redness. If you notice something stuck in your dog’s eye, don’t try to take it out yourself! Take your dog to your veterinarian right away.
What You Can Do
The list of causes of red eyes in dogs is long. You don’t have to be an expert in the causes, but you do need to recognize when your dog’s eyes are red. Take your dog to your veterinarian promptly. Your veterinarian will perform diagnostic tests to determine the cause of the redness, then prescribe the appropriate treatment.