Q: My dog recently developed a red eye. What causes this? Should I try putting human eye drops in his eye?

A: A red eye can result from any number of diseases, some of which threaten vision if not addressed quickly. So, when you see a red eye, take your pet to the veterinarian immediately.

Glaucoma, increased pressure within the eyeball, is a common cause of red eye. In pets, the pressure can rise quickly and, if untreated, cause irreversible blindness.

The white of the eye turns red when the eye’s blood vessels become engorged; sometimes the pupil is dilated, too. Glaucoma is painful in pets — yet another reason to get your dog to the veterinarian immediately.

Uveitis, an inflammation within the eye, frequently causes red eye and pain — and, if left untreated, loss of vision. Sometimes the pupil is constricted, and sometimes debris collects in the normally clear front chamber of the eye.

A corneal ulcer, a defect on the surface of the eye, often appears red because of the blood vessels growing across the cornea in the direction of the ulcer. Corneal ulcers are painful, and they can worsen until the eye ruptures and the pet becomes blind. So, they, too, must be treated immediately.

Many other conditions cause eye redness. With luck, your dog’s red eye will have a more benign cause than those I described.

Still, the key to preserving vision and minimizing pain is to get your dog to the veterinarian immediately.

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Q: Can cats be right- or left-handed like humans? When I offer my Katie Kat a bowl of kibble, she almost always uses her right front paw to remove a few pieces from the bowl and then eats them from the floor.

A: Yes, most cats do have a dominant paw, though many are ambidextrous for easy maneuvers, such as batting a toy around the floor.

Research that assigns cats more difficult tasks, such as digging food from a jar, has demonstrated that 78% of cats do indeed prefer to use either the right or left front paw. One study found that cats with a strong preference for using one paw over the other do better on problem-solving tests than cats that are not clearly right- or left-handed.

Moreover, multiple studies show that almost all female cats are right-handed, while males are overwhelmingly left-handed.

Female and male cats exhibit the same paw preferences, called “lateral bias” by scientists, when stepping over and stepping down from an object. However, this lateral bias is not seen when cats lie on their sides.

Among purebred cats, Bengals are more likely to be left-handed than right-handed, regardless of sex. The other cat breeds tested did not show breed-related paw preference.

If you want to determine Katie Kat’s handedness, try these tests:

» Place a morsel of tuna in a glass and watch which paw she uses to dig it out.

» Hide some kibble under a bowl and see which paw she uses to push the bowl aside.

» Put a bit of sticky Laxatone, canned cat food or meat baby food on her nose and note which paw she uses to remove it.

Repeat each test many times over several days to confirm which of Katie Kat’s front paws is dominant.

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Lee Pickett DVM practices companion animal medicine in North Carolina. Click here to ask her questions for her weekly column. The opinions expressed are her own.