If a White Film Covers Your Cat’s Eye — Causes of Third Eyelid Prolapse and When to Visit the Vet

Feline third eyelid prolapse may look like a protruding inner eyelid, but in most cases it’s a treatable condition. Here’s the key information every pet owner should know.

What Is Feline Third Eyelid Prolapse?

The most common form of third eyelid (nictitating membrane) prolapse in cats is "cherry eye," where the tear gland (lacrimal gland) located on the inner side of the third eyelid protrudes outward. The protruding gland appears as a smooth, pink to red mass bulging from the posterior surface of the third eyelid. While it may occur in only one eye, it is not uncommon for both eyes to be affected simultaneously. - Tear Gland Prolapse: If the connective tissue that holds the tear gland in place within the third eyelid is congenitally weak, the gland can slip out. If this condition persists, it may lead to conjunctivitis, ocular discharge, and reduced tear production, potentially resulting in secondary inflammation, bacterial infection, or corneal ulcers. - Common Age Group: This condition tends to occur primarily in young cats. - Treatable: In most cases, it can be managed through accurate diagnosis and surgical treatment by a veterinarian. This information is crucial for determining whether an immediate veterinary visit is necessary.

Why Does the Third Eyelid Prolapse in Cats?

The root cause of feline third eyelid gland prolapse (cherry eye) is a congenital failure of the connective tissue that anchors the gland in place, leading to laxity and displacement of the gland. - Congenital predisposition: This condition is more common in certain breeds, with the Burmese reported to have a predisposition in cats. - Young age: This condition tends to occur primarily in young cats. - Secondary changes: Once the gland prolapses, secondary issues such as conjunctivitis, decreased tear function, and corneal ulcers may develop. - Third eyelid prolapse due to pain: Cats may also reflexively protrude the third eyelid when experiencing ocular pain, so it is important to differentiate this from other painful eye conditions. Early identification of the underlying cause is essential.

What Are the Main Symptoms of Third Eyelid Prolapse?

The most characteristic sign of cherry eye (prolapse of the third eyelid gland) in cats is a smooth, pink-to-red mass protruding from the inner corner of the eye. - Conjunctivitis and redness: If the prolapsed gland becomes irritated, it can cause inflammation of the conjunctiva, leading to redness of the eye. - Increased discharge and crusting: Irritation of the eye may result in increased tear production or the formation of eye discharge and crusts. - Reduced tear function: If the gland of the third eyelid fails to function properly, tear production may decrease. - Corneal ulcers and vision impairment: Secondary corneal ulcers may develop due to exposure of the tissue or friction, potentially affecting vision. Early detection and treatment are essential.

How Is the Diagnosis Made?

Veterinarians typically diagnose the condition through clinical examination, directly observing the eye to assess the shape and position of the pink to red mass protruding from the third eyelid. - Ophthalmic examination: The vet examines whether the protruding tissue is the lacrimal gland and checks for curling of the third eyelid cartilage. - Tear testing: Tests such as the Schirmer tear test are used to evaluate tear production function (note that normal cats may also show low values). - Differential diagnosis: If other conditions, such as a third eyelid tumor, are suspected, a tissue biopsy may be performed for confirmation. Additionally, if the protrusion of the nictitating membrane is accompanied by miosis (pupil constriction) and ptosis (drooping eyelid), neurological issues such as Horner’s syndrome must be ruled out. - Consultation with a specialist recommended: In complex cases, diagnosis by an ophthalmology specialist is necessary. An accurate diagnosis is the first step toward effective treatment.

What Are the Treatment Options?

The primary goal of treatment is to return the prolapsed lacrimal gland to its proper position. - Surgical reduction (repositioning): The standard treatment involves placing the prolapsed gland back into the pocket of the third eyelid and securing it in place. The "Morgan Pocket" technique is the most widely used method. - Avoid gland removal: Excision of the lacrimal gland itself should be avoided whenever possible, as it can lead to complications such as decreased tear production. - Adjunctive medication: Topical or systemic anti-inflammatory drugs and antibiotics may be used before and after surgery to prevent inflammation and infection. - Post-operative care: An Elizabethan collar (protective cone) should be worn to prevent the cat from scratching its eye and causing self-injury. - Regular check-ups are essential: Chronic, severe, or previously failed surgical cases can be more complex and may require revision surgery, making regular veterinary examinations important.

Home Care Methods

Even after surgery for a cat’s third eyelid gland prolapse, consistent post-operative care is essential. - Clean around the eyes: Gently wipe away discharge from around the eyes on a regular basis using a soft cloth. - Use prescribed eye drops: Administer prescribed anti-inflammatory or antibiotic eye drops exactly as directed, following the correct dosage and frequency. - Prevent self-injury: Keep your cat’s nails trimmed to avoid scratching the eyes, and use an Elizabethan collar during the recovery period to protect the eyes. - Minimize stress: Provide a quiet, calm environment and maintain a consistent daily routine. - Monitor closely: Regularly check the eye for any changes. If you notice signs of abnormality such as redness or increased discharge, contact your veterinarian immediately.

The standard treatment is surgical repositioning that returns the prolapsed tear gland to its original place. Excision that removes the tear gland is avoided as much as possible due to the risk of complications, and treatment varies depending on the cat's condition and the veterinarian's judgment.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Related Guides

Top 5 Dog Tear Supplements Recommended for 2026

The Ultimate Guide to Managing Excessive Tearing and Tear Stains in Dogs: Top Recommendations and Selection Criteria

What is Lutein? Effects on Dog Eye Health

Checklist for Preparing to Raise Your First Puppy

Rescue Dog Adoption Procedures and Precautions – What You Must Know Before Adopting

A Complete Guide to Cat Vaccination Costs

Pros and Cons of Raw Diets for Dogs and Precautions

What is Grain-Free Food? Pros, Cons, and Selection Criteria

Spaying Female Dogs: Surgical Process and Recovery Care

How to Bathe Your Cat and Precautions