Like many animals, canines and felines have a third eyelid. In addition to upper and lower lids (similar to us humans’), they have another membrane that can close over the cornea to protect the pet from eye infection. This third eyelid is transparent in most animals, but if it’s injured or if your pet is suffering from an illness, it can become colored. If you can see the third eyelid, it’s usually a sign something is wrong with your cat or dog.
Sometimes, the eyelid doesn’t only become visible – it actually pops out and away from the cornea. In these instances, the delicate tissue bulges forth from the corner of your pet’s eye as a red bump, giving the condition the name “cherry eye.”
What Causes Cherry Eye in Dogs and Cats
In a healthy dog or cat, the third eyelid is connected to the lower rim of the eye. If the attachment is weaker than normal, the lid can stretch away and pop out.
This prolapse, or bulging, of the third eyelid is not related to any other medical condition or illnesses. And, unfortunately, there’s no way to prevent cherry eye in dogs or cats. Some pets (mostly canines) are simply genetically predisposed to the disorder. Dogs that are most at risk for cherry eye include Cocker Spaniels, Bulldogs, Beagles, Bloodhounds, Basset Hounds, Shar Peis, Maltese, Lhasa Apsos, Shih Tzus, and other brachycephalic breeds with flat faces. While cherry eye in cats is significantly less common, it does regularly affect certain breeds, especially Burmese and Persian cats.
While cherry eye seems to be most common in younger animals, a dog or cat at any age can develop it. Once a pet develops a prolapsed lid in one eye, the other eye often develops it too, although it may be months or even years later.
Symptoms of Cherry Eye
Once the eyelid pops out, you’ll immediately see the bulge, which will become a red, thick, irritated-looking bump inside the corner of your pet’s eye. Cherry eye isn’t just unsightly. This bump can be very uncomfortable for your pet, which might lead your dog or cat to rub and scratch at it; that can make the prolapsed lid increasingly more inflamed.
Cherry eye can lead to more serious eye problems if it’s not properly treated. A pet with cherry eye is at greater risk for conjunctivitis or other infection of the eye with prolapsed eyelids may also develop corneal ulcerations, which are tears on the surface of the eye. These can be very painful and itchy. Your pet will naturally want to rub and scratch at an ulcerated eye, which is dangerous since that can lead to further complications and long term problems to the health of your pet’s eye and vision.
In some circumstances the treatment of cherry eye in dogs and cats can also lead to keratoconjunctivitis sicca, or chronic dry eye, which you’ll need to manage with eye drops or other medications.
More on Eye Health
When Dogs Get Cataracts
Nuclear Sclerosis in Cats
This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.