Dry Eye, Pink Eye, Cherry Eye, a Bluish Cornea — Eye Color Warning Signs

by Dr. Becker

If your dog has red eyes, it’s important to get them checked out by a veterinarian, as redness can be a sign of inflammation or infection. In some cases, environmental exposures, such as to allergens, cigarette smoke, dirt or other irritants can cause red, irritated eyes in pets.

Even eyelash hairs that grow from an abnormal spot, a condition known as distichiasis, can rub against your dog’s cornea, causing redness, inflammation and discharge from the eye. But assuming an external irritant isn’t to blame, the redness may signal a problem with your dog’s external eyelids, third eyelid, conjunctiva, cornea or sclera of the eye. Here are some of the most common causes of eye redness to be aware of.

Dry Eye Causes Redness, Thick Discharge
Redness combined with thick, yellow discharge from the eye may be due to keratoconjunctivitis sicca (KCS), otherwise known as dry eye. Estimated to affect about 5 percent of dogs at some point during their lifetime, the condition causes your dog’s eyes to become very dry and painful. You may notice your dog blinking or squinting a lot and the eyelid may swell.

Certain breeds, including Shih Tzus, Boston terriers, English bulldogs, Cavalier King Charles spaniels and West Highland white terriers, are more likely to suffer from dry eye than others and in some cases may be hereditary.

The condition may be autoimmune in nature, when your dog’s immune system attacks the lacrimal glands that help produce tears, or can be due to a problem with the nerve to the lacrimal gland.1 It’s essential to have the dry eye treated, as left unchecked it can be very painful and even may lead to blindness.

Pink Eye
Conjunctivitis, or pink eye, can cause red eyes along with discharge and swelling. Typically caused by bacteria, pink eye infections can cause your pet to squint or paw at his eyes due to itching or pain. If the pink eye doesn’t clear up after a day or two, doesn’t respond to treatment or is accompanied by cloudiness in the cornea, you should see your veterinarian for follow-up.

In some cases, especially in Cocker Spaniels and bulldogs, pink, swollen eyes can be caused by allergies. It can also occur along with other eye conditions, including glaucoma, corneal ulceration, dry eye or intraocular inflammation. In these cases, the underlying cause must be treated to prevent eye damage and even possibly vision loss.

Red Eyes and Cloudy Cornea Could Be Glaucoma

If your dog’s eyes appear red accompanied by a cloudy or bluish cornea, glaucoma could be the culprit. This condition occurs when there is inadequate drainage of fluid, leading to increased intraocular pressure. Watery discharge from the eye, swelling or bulging of the eyeball, or eye pain may also occur.

Primary glaucoma is inherited due to an abnormality with the drainage angle in the eye. It occurs in many breeds, including the Cocker Spaniel, basset hound, chow, Jack Russell terrier, Shih Tzu and Siberian Husky. Primary glaucoma typically starts in one eye and progresses to the other and is considered a medical emergency.

Secondary glaucoma occurs when other eye diseases are present that inhibit drainage of the aqueous humor inside the eye. These diseases include inflammation of the eye (uveitis), advanced cataracts, cancer of the eye, lens displacement and chronic retinal detachment. Glaucoma can cause permanent blindness, so take your dog to the veterinarian immediately if you suspect glaucoma.

Cherry Eye — Prolapse of the Third Eyelid

Your dog has a third eyelid in the corner of each eye, located underneath the lower lid. It houses a tear gland and, when healthy, remains tucked away and can’t be seen by looking at your dog. Sometimes, the gland may pop out or prolapse, leading to a bright red bulge known as cherry eye.

It may be large and very obvious or small and discrete. It may remain prolapsed or come and go. Certain breeds seem to be more prone to cherry eye than others, perhaps because of a weak attachment between the third eyelid and the lower inner eye rim. Breeds most affected include Cocker Spaniels, bulldogs, Boston terriers, beagles, bloodhounds, Lhasa Apsos, Shih Tzus and other brachycephalic breeds.

While cherry eye isn’t typically painful to dogs, once the gland pops out it can become increasingly inflamed and is vulnerable to infection. Further, because the gland is no longer seated in its normal position, it can prevent adequate lubrication of the eye.

Unfortunately, it’s sometimes advised to remove the gland in order to treat cherry eye, versus replacing the gland, surgically, even though it’s necessary for adequate lubrication of the cornea. Removing the gland very often results in lifelong dry eye, which requires owners to manually lubricate their dog’s eyes for the rest of their lives or face eventual blindness.

I strongly recommend you demand gland replacement if your dog is suffering from this condition. Removing the gland is unnecessary and ultimately can decrease quality of life for many years down the road.

Alternatively, an aggressive protocol of herbal eye drops, prescription-only homeopathics and nutraceuticals can often help control the inflammation and reestablish the integrity of the ligaments that are designed to hold the gland in place if the condition is addressed immediately by an integrative veterinarian.

Any Changes in Your Dog’s Eyes Should Be Checked Out
The eyes can act as a window to your dog’s overall health, and many underlying chronic conditions can cause symptoms that emerge in the eyes. If you notice any changes in your dog’s eyes, including redness or other discoloration, or vision, it’s important to get it checked out sooner rather than later. Often, eye conditions are treatable if caught early on but may progress to permanent vision loss if ignored or not discovered until it’s too late.