Cherry eye is a common ocular condition in dogs characterized by the prolapse or protrusion of the gland of the third eyelid, also known as the nictitans gland or nictitating membrane gland. Dogs have a third eyelid, the nictitating membrane, located in the inner corner of each eye, which contains a tear-producing gland that contributes significantly to the eye's tear film. When the connective tissue holding this gland in its normal position weakens or fails, the gland pops out from behind the third eyelid and becomes visible as a pink or red, oval-shaped mass at the inner corner of the eye. The condition gets its name from the resemblance of the prolapsed gland to a small cherry. Cherry eye is most commonly seen in young dogs, typically developing within the first two years of life, and certain breeds are particularly predisposed.
The underlying mechanism of cherry eye involves weakness or congenital absence of the connective tissue attachments that normally anchor the nictitans gland behind the third eyelid. In healthy dogs, the gland is firmly attached to the orbital rim by fibrous connective tissue and remains hidden from view. When these attachments are weak, which is thought to be a hereditary trait in predisposed breeds, the gland can pop out of position, particularly when the dog is excited, stressed, or the eye is irritated. Once prolapsed, the exposed gland becomes swollen and inflamed from exposure to air and irritants, making it appear larger and redder than normal. The condition may affect one eye initially, but bilateral involvement occurs in a significant percentage of cases.
The impact of cherry eye on affected dogs extends beyond cosmetic concerns to potential effects on eye health and comfort. The nictitans gland produces approximately thirty to fifty percent of the aqueous portion of the tear film, making its proper function essential for maintaining eye lubrication. A chronically prolapsed gland may become damaged and produce fewer tears, potentially leading to dry eye later in life. The exposed, inflamed gland can cause discomfort, leading dogs to paw at their eyes or rub their faces. Secondary conjunctivitis and eye irritation commonly accompany the prolapse. While cherry eye itself is not a medical emergency, prompt veterinary attention helps ensure appropriate treatment and the best long-term outcomes for eye health.
Treatment for cherry eye has evolved significantly over the years, with modern surgical techniques focusing on preservation and repositioning of the gland rather than removal. Surgical correction is the treatment of choice and typically involves repositioning the gland to its normal location and securing it with sutures using one of several established techniques. When performed by an experienced surgeon, these procedures have high success rates and preserve the gland's tear-producing function. Early surgical intervention, before chronic changes develop in the gland, generally offers the best outcomes. Dogs that have undergone successful cherry eye surgery typically go on to have normal eye health, though follow-up monitoring is recommended to watch for recurrence or development of dry eye.
