Cherry Eye in Cats: An Overview
Dog Breeds
Cherry eye in cats is a condition in which the third eyelid falls down or slips out of place and is then visible in the corner of the cat’s eye. Unlike people which only have 2 eyelids, cats have another eyelid that is normally invisible otherwise known as the nictitating membrane. The function of this third eyelid is to help protect and moisturize the eye through its tear gland.
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Definition
“Cherry eye” is an eversion of the ocular nictitating membrane (third eyelid) caused by hypertrophy and prolapse of the gland associated with that membrane. The nictitating membrane is a thin sheet of tissue that normally is well-anchored to surrounding eye tissue. When prolapsed, the third eyelid gland becomes visible and appears as a red mass bulging from the inside corner of the cat’s eye.
How “Cherry Eye” Affects Cats
“Cherry eye” is rare in cats. When it does occur, the red protrusion at the inner corner of the eye usually is the only noticeable clinical sign. Redness, swelling, excessive tearing and other signs of eye irritation can also occur. “Cherry eye” can occur in one or both eyes, at the same or at different times, and usually happens quickly. The primary function of the nictitating membrane is to moisturize and physically protect the eye - particularly the cornea. The gland within that membrane produces much of the fluid that makes up tear film. When this gland is prolapsed, the eyes become red, dry, irritated and inflamed from abnormal environmental exposure and disruption of normal tear production. “Cherry eye” should be treated promptly to prevent permanent ocular complications.
Causes of Feline “Cherry Eye”
The precise cause of “cherry eye” is not known. Some cat breeds are predisposed to prolapsed third eyelids, including the Burmese and the Persian, suggesting a genetic component. There is no known gender predisposition. It is suspected that this condition happens as a result of some hereditary or congenital weakness of the fibrous connective tissue that anchors the nictitating membrane to the periorbita (the eyeball).
Preventing “Cherry Eye” in Cats
There is no known way to prevent the occurrence of “cherry eye” in cats or in dogs. The condition typically appears suddenly and without warning. Surgical repositioning and permanent suturing of the third eyelid to underlying tissue is the best way to prevent further incidents.
Special Notes
If your cat develops what appears to be “cherry eye,” consult with your veterinarian as soon as possible. If you notice any unusual ocular discharge, you can gently remove it with a soft moistened tissue.
Symptoms and Types