When people use their eyes too much, or are too tired and don’t rest well, their eyes will produce red bloodshot eyes. The same symptoms will also appear in dogs. If your dog’s eyes have red bloodshot eyes, this may be a sign of inflammation or infection. .

In some cases, environmental exposure, such as allergens, smoke, dust, or other irritants, can cause your pet's eyes to become red and inflamed.

Sometimes abnormally long eyelashes may rub against the dog's cornea, causing eye redness, inflammation, and pus discharge.

Here are some of the most common causes of red eyes in dogs.

1. Dry eye syndrome

Red, swollen eyes coupled with yellow discharge may be dog keratoconjunctivitis (Kcs), also known as dry eye.

This condition can cause your dog’s eyes to become very dry and painful. The dog may blink frequently or squint, and his eyelids may become swollen.

Certain breeds, including Shih Tzus, Boston Terriers, English Bulldogs, Cavalier King Charles Spaniels, and West Highland White Terriers, are more susceptible to dry eye syndrome than others.

Treatment of dry eye syndrome is very necessary. If left unchecked, the dog will be very painful and may even lead to blindness.

　2. Pink eyes

Conjunctivitis, or pink eye, can cause redness, swelling, and discharge from the eyes. Conjunctivitis is usually caused by bacteria, and eye infections can cause your pet to paw at his eyes because of itching or pain.

If the symptoms of pink eye do not resolve within a day or two, or are accompanied by corneal clouding, you should see your veterinarian.

In some cases, especially in Cocker Spaniels and Bulldogs, pink eyes and swollen eyes may be caused by allergies. Other eye conditions, including glaucoma, corneal ulcers, dry eye, or inflammation within the eye may also cause this condition. The underlying cause must be treated to prevent eye damage.

3. Glaucoma

If your dog’s eyes appear red and bloodshot along with gray or blue corneas, glaucoma may be the culprit. This condition occurs when intraocular pressure increases. The eyes will discharge watery eye stains, and the eyeballs will become painful, swollen, or even bulging.

Primary glaucoma is hereditary and occurs in many breeds, including Cocker Spaniels, Bassets, Chow Chows, Jack Russell Terriers, Shih Tzus and Siberian Huskies.

Primary glaucoma usually starts in one eye and progresses to the other and is considered a medical emergency.

Secondary glaucoma is usually caused byCaused by other eye diseases, including uveitis, advanced cataracts, eye cancer, lens displacement, and chronic retinal detachment. Glaucoma can cause permanent blindness. If you suspect your dog has glaucoma, take your dog to the veterinarian immediately.

4. Cherry Eyes

There is a third eyelid at the corner of each eye of the dog, located under the lower eyelid. When it's healthy, it's hidden from view. When glands protrude or fall out, resulting in red bumps, this is commonly known as cherry eye.

Some breeds seem to be more prone to cherry eye than others, possibly because their third eyelids have a weaker attachment to their lower eyelids. Breeds most affected include cocker spaniels, bulldogs, Boston terriers, beagles, bloodhounds, Lhasa Apsoos, Shih Tzus and other brachycephalic dogs.

Although cherry eye does not cause severe pain in dogs, once the gland pops up, it can become increasingly red and swollen, making it susceptible to infection.

Doctors sometimes recommend removing the glands to treat cherry eye, but this often results in lifelong dry eye syndrome, requiring owners to help keep their dogs' eyes moist to prevent eventual blindness.

Any changes in your dog’s eyes should be checked

Eyes are a window into your dog’s overall health, and many potential diseases can cause eye symptoms.

If you notice changes in your dog's eyes, including redness, graying, decreased vision, excessive eye scum, and other symptoms, it's important to get them checked out as soon as possible. Often, the eye condition is treatable, and it should be treated early before it progresses to permanent vision loss. Article source: Paite Angel public account