Red Eyes

This seems like a good time of year to talk about red eyes.  Certainly mine are!  My excuses might be staying up late at night, or having one glass of wine too many.  But my cat’s eyes are red too, and I’m sure he does not share those extravagances.  Red eyes come from so many different causes.

We think of blepharitis - an inflammation of the lids.  Or conjunctivitis, where the delicate tissue surrounding the eye is irritated.  Then there’s Cherry Eye, the protrusion of the third eyelid gland which gets stuck out of place in breeds like cockers or English Bulldogs.   We all know what bloodshot eyes look like and many of the causes - fatigue, allergy, or irritants on the surface of the eye. 

Sometimes we catch a glimpse of the shimmering red/gold/green reflection of an animal’s tapetum, the reflective part of the retina.  That demonic glow is normal anatomy in lightly pigmented individuals. 

As you can see, many structures in and around the eye can be red.  But it’s rarely normal.  With the exception of the retina, eyes should not be red.  So what are the causes of the color change?

Every one of us has rubbed his or her own eyes when we shouldn’t have, creating or responding to an irritation.  Wind-blown particles can damage delicate ocular tissues.  So please don’t drive down the road with your dog’s head all the way out of the car window!  Road debris can act like projectiles striking the eye.  We’re all aware of the havoc pollen can wreak on conjunctival membranes.  And this time of year, with our houses closed up and windows rarely open, indoor air can stagnate.

Whether from cigarette smoke, perfumes, scented candles or plug in fresheners, indoor air can be heavy with particulates. Carpets also trap dust mites and dirt, which exacerbate allergies.   Hepa filters and humidifiers go a long way to restoring the freshness of the air quality and assuage irritated ocular and respiratory tissues. 

My cat Chewbacca’s eyes are red because of allergy.  He suffered no such distortion when he lived in New England.  After his arrival in Maryland, his allergies started:  his eyes became red, his ears produce more wax, he sneezes and snorts.  All allergic symptoms in cats.  Topical steroids will ameliorate these signs and give comfort.

When it comes to cherry eye however, the treatment is surgical.   Since the problem often appears when pups are less than one year old, the repair can be combined with spay or neuter surgeries.   Effecting the repair is a good idea since an everted third eyelid can cause decreased tear production and dry eye later in life.  Cherry eye rarely occurs in cats, but when it does the Burmese typically is the affected breed.

The gorgeous tapetum is a colorful area of the retina which improves low light vision.  That’s the reason it’s more prominent in cats who are more nocturnal than people or dogs.  It allows them to see better at night.

There are many reasons for color variations in eyes.  But red is one we shouldn’t see too often.