Cherry eye is a frightening sight. It happens when a cat's third eyelid becomes inflamed and red, resembling a small cherry. Also seen in dogs and rabbits, this condition is more than just a cosmetic issue, Cherry eye is often painful, particularly if a cat aggressively rubs the eye with its paw, and it can lead to ulceration or infection. Treatment is not always necessary, but eye drops are often helpful. In rare cases, surgery is required to repair the eyelid and prevent recurrence. Brachycephalic (flat-faced) cats like Persians are more susceptible to cherry eye because of their large, protruding eyes.
What Is Cherry Eye?
Cherry eye is a nickname for a prolapsed nictitating membrane. This membrane, commonly called the third eyelid, is the innermost layer of eyelid tissue that helps protect a cat's eye. When functioning properly, it's rarely seen because it is tucked against the corner of the eye socket. If it gets enlarged and protrudes or prolapses, the membrane swells and reddens into a visible "blob" of tissue along the edge of the eye.
Symptoms of Cherry Eye in Cats
A pink or red, fleshy protrusion coming from the inner corner of a cat's eye is likely cherry eye. It is often described as a pink bubble or swelling and may be large enough to block part of a cat's eye. It can also come and go or be present permanently.
WIth cherry eye, the cat's eye may be dry due to a non-functional nictitating membrane, decreased tear production from the membrane, or the inability to close the eyelids completely. If the eye is dry, it will become inflamed, feel irritated, and itch. A corneal ulcer can form as a result. Dry eye, also known as keratoconjunctivitis sicca (KCS), may need to be treated habitually to avoid corneal ulcers. A corneal ulcer is very painful and can lead to permanent eye damage.
Causes of Cherry Eye
Cherry eye most often occurs due to abrasion (rubbing, pawing) due to an external irritant. The third eyelid swells up, turns inside out, and flips out in front of the eye. Other contributing factors include:
- Foreign particles: Dirt, grass, or other material get caught in the eye and cause irritation.
- Size of the eye socket: Brachycephalic cats may be more prone to experiencing cherry eye because their large eyes crowd the eye sockets, making the third eyelids more visible with the least bit of inflammation.
- Weak retinaculum: The retinaculum stabilizes the tendons that help hold the third eyelid in place. Sometimes, it is weak from birth or becomes too weak to do its job, so the membrane pops out.
Diagnosing Cherry Eye in Cats
Cherry eye is very recognizable by a veterinarian. Once the condition is identified, the real diagnostic challenge is finding the cause. Your vet may closely examine your cat's eye to check for any foreign particulate matter. If the cause is eye socket size or a weak retinaculum, your vet will likely warn you that recurrence of cherry eye is likely.
Depending on the severity of the cherry eye, treatment may not even be necessary. Some cherry eyes will come and go on their own while others will pop out and stay out. Your vet may carefully tuck the membrane back into the eye socket. Manual, gentle pressure on the gland may replace it, but it will often come back out.
But if the cherry eye is chronic and causing ongoing problems, surgery might be recommended to correct the physical abnormality. A surgical procedure can "stitch" the gland back into place to allow the inflammation to subside so that the membrane can resume lubricating the eye. Occasionally, the gland will be removed if it is no longer serving its function of providing tears to the eye.
If secondary problems have developed due to a cherry eye, ophthalmic ointments or eye drops may need to be applied to help heal corneal ulceration.
Prognosis for Cats with Cherry Eye
Cherry eye isn't a critical condition, but chronic cases indicate an inflammatory issue with the eye that will require treatment to resolve. The worst-case scenario is loss of vision due to severe corneal scarring, but this is a rare occurrence.
How to Prevent Cherry Eye
Unfortunately, there is no reliable way to prevent cherry eye in cats. If a cat is born with a weak retinaculum or a small eye socket, there is nothing you can do to prevent a cherry eye from happening. You can, however, be vigilant about making sure your cat's eyes do not get too dry by using eye drops as recommended by your vet.