Cherry eye in dogs is caused by weakness in the connective tissue that holds a small tear-producing gland in place behind the third eyelid. When that tissue stretches or gives way, the gland pops out of position and bulges into view as a pink or red, rounded mass in the inner corner of the eye. This is considered a structural defect that dogs are born with, and certain breeds face dramatically higher risk than others.
The Anatomy Behind Cherry Eye
Dogs have a third eyelid, sometimes called the nictitating membrane, tucked in the inner corner of each eye. Most owners never notice it. This membrane has its own tear gland attached to its base, responsible for producing a significant portion of the eye’s tear film. In a healthy eye, a band of connective tissue anchors this gland firmly to the cartilage of the third eyelid, keeping it hidden from view.
Cherry eye happens when that anchoring tissue is too loose or too weak to do its job. The gland slips out of position and prolapses, pushing forward and appearing as a smooth, round, pink or red lump. It’s not a tumor or a growth. It’s normal tissue that has simply moved to the wrong place. The condition is thought to be a juvenile, probably hereditary defect in the connective tissue itself, which is why cherry eye overwhelmingly appears in young dogs, typically under two years old.
Why Certain Breeds Are at Much Higher Risk
Genetics play the biggest role in determining which dogs develop cherry eye. A large study found that Neapolitan Mastiffs are 34.3 times more likely to develop the condition compared to mixed-breed dogs. English Bulldogs aren’t far behind at 24.1 times the risk. Other high-risk breeds include the Lhasa Apso (12.4 times), American Cocker Spaniel (11.6 times), Puggle (9.5 times), Great Dane (6.2 times), and Saint Bernard (5.3 times).
A clear pattern runs through that list: many of these breeds have flat faces. The same research found a significant correlation between skull length and cherry eye risk. Brachycephalic breeds (those with shortened skulls and pushed-in faces) are up to seven times more likely to develop the condition than dogs with normal skull proportions. The compressed facial anatomy in these breeds likely changes the shape and depth of the eye socket, putting extra strain on the already vulnerable connective tissue holding the gland in place. No single gene responsible for cherry eye has been identified, but the strong breed predisposition points to inherited structural traits rather than any environmental trigger.
What Cherry Eye Looks and Feels Like
The hallmark sign is hard to miss: a smooth, pink or red mass of tissue protruding from the inner corner of the lower eyelid. It can range from the size of a small pea to something much more prominent, and it may appear suddenly. Some dogs have cherry eye that comes and goes early on, with the gland popping in and out before eventually staying prolapsed.
Cherry eye can affect one eye or both. When it shows up in one eye, there’s a reasonable chance the other eye will eventually follow, since the underlying connective tissue weakness is present on both sides. The exposed gland can become irritated and swollen from contact with air and debris, which may cause your dog to paw at the eye, produce excess tears, or develop discharge.
Conditions That Look Similar
Not every red lump in a dog’s eye is cherry eye. A condition called scrolled cartilage can look nearly identical. In this case, part of the cartilage within the third eyelid grows abnormally, bending or curling to create a pink or red swelling in the same location. Scrolled cartilage can occur on its own or alongside cherry eye, and distinguishing between the two sometimes requires an exam under anesthesia. In rare cases, tumors of the third eyelid can also mimic cherry eye. A veterinarian will typically diagnose cherry eye based on a physical exam and may perform a tear production test to check gland function and look for any cartilage abnormalities.
Why the Gland Should Be Saved, Not Removed
Decades ago, the standard treatment for cherry eye was simply cutting the prolapsed gland out. This solved the cosmetic problem but created a much worse one. The third eyelid gland produces a substantial share of your dog’s total tear output. Removing it leaves the eye permanently short on moisture, often leading to chronic dry eye, a painful condition that requires lifelong daily eye drops and can damage the cornea over time.
Modern veterinary practice strongly favors surgical repositioning, where the gland is tucked back into its normal position and secured there. The two most common techniques are the pocket method, where the gland is enclosed in a small pouch of tissue sutured around it, and anchoring, where the gland is stitched to deeper structures near the eye socket rim. Both approaches have similar success rates, with surgical failure (the gland popping back out) occurring in only about 2 to 3 percent of cases. When performed by a veterinary ophthalmologist, the overall success rate is approximately 92 percent, with proper post-operative care improving outcomes further.
What Recovery Looks Like
After repositioning surgery, expect the eye to be noticeably red and swollen for about 10 to 14 days. Your dog will need to wear a protective cone for the first one to two weeks to prevent rubbing or scratching at the surgical site. Post-operative care typically involves oral pain relief and antibiotic or anti-inflammatory eye drops or ointment. Most dogs bounce back quickly once the initial swelling fades.
Recurrence is the main concern after surgery. While the 2 to 3 percent failure rate is reassuring, young dogs and certain high-risk breeds are more prone to re-prolapse. If cherry eye does recur, a second surgery using the same or a different technique is usually successful. Even with a repeat procedure, preserving the gland remains the priority to protect long-term tear production and eye health.
What Happens If Cherry Eye Goes Untreated
Cherry eye is not a medical emergency, but leaving it alone indefinitely is not a benign choice. The longer the gland sits exposed outside its normal position, the more irritated and swollen it becomes. Chronic inflammation can damage the gland tissue, reducing its ability to produce tears even after it’s eventually repositioned. That puts the eye at risk for the same dry eye complications that come with gland removal, just through a slower process of damage rather than surgery. Early repositioning, while the gland is still healthy and functional, gives the best chance of preserving full tear production for the rest of your dog’s life.