It may not be pretty, but the good news about the condition known as “cherry eye” is that it is typically more of a nuisance than a medical emergency.
Dogs and cats have, in each eye, a nictitating* membrane, which is commonly referred to as a “third eyelid.” You may have noticed the thin, white sheet of tissue that appears to cross the eye diagonally, when your pet blinks.
*Nictitating means winking.
The third eyelid is positioned at the inside corner of the eye, between the outer lids and the eyeball. It helps protect the eye, as a physical barrier and by spreading tears over the surface of the cornea with each eye blink.
The third eyelid also has a gland which produces tears. It is this tear gland that sometimes falls out of place (an event known as a prolapse), swells, and assumes the appearance of a cherry, due to irritation and poor blood circulation.
Cherry eye is more commonly seen in dogs than in cats. Dogs most often affected by cherry eye are Bulldogs, Cocker Spaniels, Beagles, Boston Terriers, and ShihTzus. Burmese and Persian cats are thought to be more at risk than other cat breeds. In either species, cherry eye can appear in one or both eyes.
In some pets, a cherry eye will appear and disappear on its own, at intervals. In others, once the tear gland has prolapsed, it will not return to its proper size and position without surgical intervention.
A popular current surgical technique is the tuck, in which the prolapsed gland is tacked into place with a suture. No surgery is without risk, however; in this case, the tuck may not hold, leading to repeat surgeries.
In the past, when the role of the third eyelid was not as well understood, surgeons removed the gland altogether, which carried the risk that the pet would develop “dry eye” from a lack of sufficient tear production. In the current tuck technique, the gland remains attached, so that it can continue producing tears, which protect the eye.
Although cherry eye is not life-threatening, it can lead to further problems if left untreated. The prolapsed gland may become injured or infected, since it was not designed to be exposed to elements outside the body. As a result of injury or infection, the pet’s eyesight could be harmed.
If you notice a red swelling at the inside corner of your pet’s eye, it could be a prolapsed tear gland. Have your vet check it out to be sure; if it is a cherry eye, your vet will recommend the proper treatment.
Note: This article is for informational purposes and is not meant to diagnose or suggest a course of treatment for any pet. As always, your veterinarian is the best source of information, and he or she can provide a professional medical opinion upon examining your pet.
This article originally appeared on January 10, 2013.