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Latest health and behavior news and advice from the veterinarians at Tufts University.

Features April 2014 Issue

The Eyes Have It — But They Shouldn’t

Recognizing signs of serious eye problems.

If the gook in your dog’s eye is white to clear and in the eye’s inner corner, “that’s normal,” says veterinary ophthalmologist Nancy Bromberg, VMD, MS, DACVO, chair of the public relations committee for the American College of Veterinary Ophthalmology. “Almost all dogs have that.

“I recommend just using good old warm water on a cotton ball to get out the ‘gook,’ comments the doctor, who treats pets’ eyes at her practice in Fairfax, Virginia, a suburb of Washington, DC. “You don’t want to rub the eye and get cotton into it. Just go along the lower lid. Usually the discharge will be thick and tenacious and stick to the cotton ball. It will then pull right out.

“Only start worrying if it becomes excessive,” Dr. Bromberg cautions. “If you clean it away and it’s back in five minutes, something’s going on that shouldn’t be” and a trip to the veterinarian is in order.

Excessive discharge is just one sign that your dog’s eye health — and vision — may be at risk. There are a number of other signs in the eye that mean a prompt visit to the vet, sometimes straight to a veterinary ophthalmologist as opposed to your dog’s usual doctor, is in order. Herein, a look at the most common warning signals.

Red eye. “Red eye is a red flag,” says Dr. Bromberg. It’s non-specific, meaning it can be indicative of a lot of different conditions. If it resolves on its own within 24 hours, “it was probably just a minor irritant causing the discoloration,” she says. “But some conditions signified by red eye are serious and require prompt treatment. Among the potential maladies: anything from an allergic reaction to a corneal ulcer — trauma in the form of a tear or other disfiguration in the cornea, which is the transparent, protective covering over the eye.

In some cases, red eye can be indicative of intra-ocular inflammation — inflammation somewhere within the eye. Some of the causes of that include blunt trauma and tick-borne diseases, including Lyme disease. “If there’s acute onset red eye,” Dr. Bromberg notes, meaning it comes on all of a sudden, “I would probably not wait more than a day to see a veterinarian if it doesn’t resolve on its own.” Especially if the condition is accompanied by discomfort or decreased vision — the discomfort may come in the form of the dog keeping her eye closed or going off by herself as if she has a bad headache — you should not delay going to the veterinarian, and in that case, perhaps straight to an ophthalmologist. The pain could be a sign of sudden onset cataract or glaucoma — high pressure in the eye that has to be treated very fast to avoid blindness. With glaucoma (the eye may look very inflamed), the pain might be so bad that it can cause a dog to lose her appetite and even vomit.

Pus-like discharge. The typical white-to-clear discharge dog owners commonly see is not pus. Pus, to use the vernacular, is generally what people think of as green to greenish-yellow, and it’s often about inflammation, just like with red eye, but it tends to mean that the situation is more severe.

Why the green or yellow color? “If an eye is inflamed for some reason,” Dr. Bromberg says, its response is to produce discharge. Since bacteria are always all around the eye, they make their way into the discharge and “set up house” there, changing it from a clear-to-white mucus to the yellow-green ugly-looking stuff.

“People think discharge is always about an infection,” adds Dr. Bromberg, “but it doesn’t mean infection as much as it means inflammation. Yes, there’s a bacterial component, but not necessarily a true infection. If you see this type of discharge, assume inflammation, not automatically†an infection.”

One of the main causes for inflammation characterized by thick, colored discharge in a dog is dry eye, known in medical circles as keratoconjunctivitis sicca. If the eye is not getting enough tears, the glands that produce mucus and oils start to over-produce in an effort to compensate, and bacteria migrate to the viscous material. Dry eye is actually “one of the major causes for green-to-yellow discharge in a dog’s eye,” Dr. Bromberg says. Other causes include foreign bodies either in the cornea or under the dog’s third eye lid or embedded in the conjunctiva — a thin membrane that covers the inner surface of the eyelid and the white of the eye. Foreign bodies tend to get stuck in different parts of a dog’s eye if she “runs through tall grasses or likes to push her face into bushes,” Dr. Bromberg says.

Then there are the non-foreign bodies that cause problems. Sometimes the green-to-yellow discharge is about entropion: the lids roll inward so that hairs normally on the outside are now rubbing on the cornea. It requires a surgical solution.

“Extra lashes growing in the wrong direction can also poke into the cornea,” Dr. Bromberg says. “Instead of curling away from the eye, they curl toward the eye.” These extra lashes should never be plucked, but, rather, permanently removed with electroepilation or cryosurgery.

A corneal ulcer can also come with a lot of bacteria-laden discharge. In the case of a corneal ulcer, Dr. Bromberg notes, “there is potentially an infection setting in.”

Swollen area around the eye. Most commonly, swelling around the eye comes from either trauma or an acute allergic reaction. But sometimes it’s part of an autoimmune reaction. For instance, says Dr. Bromberg, there can be autoimmune problems involving the muscles of the eye, a condition called myositis. That can cause the eyes to look “very bulgy,” she says — “Marty Feldman eyes.”

Acute onset glaucoma can also make the eyes look very swollen. “Definitely have it looked at by a veterinarian sooner than later,” Dr. Bromberg cautions.

Sudden color change. If the pupil goes from black to white, it means a cataract is forming. (Grayish is usually an age-related change.) And if the eye looks red — not just the white of the eye but the whole eye, pupil and brown or blue iris included — it means there has been hemorrhaging. “All you’ll see is red,” Dr. Bromberg notes. “The eye will look like an 8 ball.” Inflammation of the tissue that lines the eye — conjunctival tissue — can make that area look red, too.

Along with changes in color can come changes in transparency. In cases of glaucoma, the cornea, instead of being crystal clear and see-through, can look cloudy — as opposed to white, as is the case with a cataract. That’s “truly a medical emergency,” Dr. Bromberg says. The surface of the eye becomes hazy because of edema, or fluid in the cornea. It’s the pressure that causes the change, and it has to be treated right away to save the dog’s vision.

Closed lid. As indicated above, if a dog holds her eye closed (“blepharospasm” in medical terms), it’s usually indicative that there’s discomfort, if not outright pain. Sometimes it’s light sensitivity. Or it could be an indication of entropion or extra lashes. “Every time the dog blinks, the hairs on the lid or the extra lashes rub on the eye, which is very uncomfortable,” Dr. Bromberg points out. A dog will also keep her eye closed if she has a corneal ulcer or inflammation somewhere inside the eye.

Other signs of pain or discomfort: lethargy; coming over to you and pressing against you; and an itchy eye. If a dog keeps rubbing at her eye, it can be a sign of any the conditions discussed.†

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