Cherry Eye in Dogs: Recognizing Prolapse of the Nictitating Membrane Gland
Cherry Eye in Dogs: Recognizing Prolapse of the Nictitating Membrane Gland
What is cherry eye in dogs?
Cherry eye (nictitating membrane gland prolapse, prolapse of the nictitating membrane gland) is the protrusion of the gland of the third eyelid from its normal position. The gland prolapses over the edge of the nictitating membrane cartilage and appears as a reddish, fleshy, round lump in the medial canthus (inner corner of the eye)—characteristically resembling a red cherry, hence the English term.
Cherry eye is not a disease of the gland itself, but rather a positional abnormality: the connective tissue that anchors the gland to the periorbital region is too weak or tears, causing the gland to protrude outward. The gland is intact and functional—which is why preserving it is the goal of treatment.
Background + Scientific Context
Gelatt (2013, *Veterinary Ophthalmology*, 5th ed.) describes the anatomy and pathogenesis: The nictitating gland (Harder’s gland) produces approximately 30–35% of the precorneal tear film in dogs. Its attachment to the periorbital region via retinacular ligaments is genetically weak in certain breeds—a predisposition that can also occur bilaterally. Predisposed breeds: Cocker Spaniel, English Bulldog, Beagle, Lhasa Apso, Boston Terrier, Rottweiler, Shar Pei. Untreated prolapse leads to chronic exposure, dryness, secondary conjunctivitis, and fibrosis of the gland.
Mazzucchelli et al. (2012, Veterinary Record, https://pubmed.ncbi.nlm.nih.gov/22438310/) conducted a retrospective study of 155 cases over an 8-year period: Cocker Spaniels and brachycephalic breeds were overrepresented. In 38% of cases, a bilateral prolapse developed. The pocket technique (Morgan technique) showed the lowest recurrence rate (approx. 12%). Gland removal was associated with a significantly increased incidence of keratoconjunctivitis sicca (dry eye).
Kaswan and Martin (1985, Journal of the American Veterinary Medical Association, https://pubmed.ncbi.nlm.nih.gov/4038375/) described the surgical repositioning method involving the placement of the gland into a conjunctival pocket (pocket technique): The gland is repositioned and secured with a conjunctival suture—without removal. This technique forms the basis of today’s surgical standard and preserves lacrimal gland function.
Vitomalia-Position
A cherry eye must be repositioned—never removed. The gland produces over 30% of the tear film. Removal increases the risk of keratoconjunctivitis sicca (dry eye), a chronic, painful condition that requires lifelong use of eye drops. Surgical repositioning by a veterinarian with expertise in ophthalmology is the only treatment recommended by guidelines.
When does cherry eye become a concern?
- A red, fleshy lump in the inner corner of the eye — on one side or both sides
- Breeds prone to the condition (Bulldog, Cocker Spaniel, Beagle, Boston Terrier)
- Red eye, increased tearing, or rubbing the eye
- Young dogs are more commonly affected (under 2 years of age)
- Recurrence following spontaneous reduction (incomplete fixation)
Practical application
A Comparison of Surgical Methods:
| Method | Principle | Recurrence rate | Recommendation |
|---|---|---|---|
| Pocket Technique (Morgan) | Gland sutured into the conjunctival sac | ~12% | gold standard |
| Anchor Technology (Kaswan) | Gland attached to the periorbital region | 5–15% | Alternative |
| Interlocking (Raffnaht) | Cartilage-conjunctival flap | ~15–20% | Less common |
| Gland removal | Excision of the gland | — | Contraindicated |
Post-operative care: - E-collar for 10–14 days: no rubbing, no scratching - Eye drops (antibiotic + corticosteroid) for 2–3 weeks - Check the contactor after 7–10 days - Long-term: Monitor tear production (Schirmer tear test) — even after a successful surgery
Risks without treatment: - Chronic exposure of the gland → fibrosis → permanent gland dysfunction - Secondary conjunctivitis and corneal irritation - Increased risk of developing keratoconjunctivitis sicca later on, even without removal
Common Mistakes & Myths
- “You can simply remove the gland—and the problem is gone.” Wrong—the gland produces more than 30% of the tear film. Removing it significantly increases the lifetime risk of keratoconjunctivitis sicca. Repositioning is the only method recommended by clinical guidelines.
- “Cherry eye usually resolves on its own.” Spontaneous repositioning occasionally occurs—but it is unstable and incomplete. Without surgical fixation, the gland will prolapse again. Gland fibrosis caused by chronic exposure is irreversible.
- “Cherry eye is a minor issue.” If left untreated, cherry eye can lead to permanent gland damage, eye irritation, and an increased risk of KCS. Early surgical treatment significantly improves the long-term prognosis.
Current State of Research (2026)
Cherry eye is well understood in veterinary ophthalmology. Current research is examining genetic factors underlying connective tissue weakness in predisposed breeds and the long-term outcomes of various surgical techniques. Consensus: Preservation of the gland using the pocket or anchor technique is the standard of care—excision is contraindicated. There are no preventive measures; selective breeding in heavily affected breeds is under discussion.
Frequently Asked Questions
What is cherry eye in dogs, and what does it look like?
Cherry eye is the prolapse of the nictitating membrane gland—it protrudes from its normal position and appears as a red, round lump in the inner corner of the eye. It can occur on one or both sides and is common in certain breeds.
Does a cherry eye require surgery?
Yes—surgical repositioning is the treatment of choice. The gland must be preserved (it produces over 30% of the tear film). Removal of the gland is contraindicated and increases the risk of permanent dry eye.
Which breeds are particularly prone to cherry eye?
Cocker Spaniels, English Bulldogs, Beagles, Boston Terriers, Lhasa Apsos, Shar Peis, and Rottweilers are at increased genetic risk. Brachycephalic breeds are generally overrepresented. The condition usually develops before the age of 2.
Related terms
Sources & Further Reading
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Gelatt, K. N. (Ed.) (2013). Veterinary Ophthalmology (5th ed.). Wiley-Blackwell. ISBN 9780470960875.
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Mazzucchelli, S., Vaillant, M. D., Wéverberg, F., Arnold-Tavernier, H., Honegger, N., Payen, G., … Chahory, S. (2012). Retrospective study of 155 cases of prolapse of the nictitating membrane gland in dogs. Veterinary Record, 170(17), 443. https://pubmed.ncbi.nlm.nih.gov/22438310/
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Kaswan, R. L., & Martin, C. L. (1985). Surgical correction of third eyelid prolapse in dogs. Journal of the American Veterinary Medical Association, 186(1), 83–84. https://pubmed.ncbi.nlm.nih.gov/4038375/