Prolapsed third eyelid (nictitating membrane) in Dogs
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
ORANGE for eye pain, corneal cloudiness, impaired vision, trauma, or if the eye looks sunken (dehydration/pain).
Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity
Definition
Prolapse of the third eyelid, also called a prolapsed nictitating membrane, is a condition in which the dog’s third eyelid—normally hidden in the inner corner of the eye—becomes visible and protrudes over part of the eye.
Can Occur with the Following Diseases:
- Brachial Plexus Avulsion in Dogs (Brachial Plexus Injury)
- Inner Ear Infection in Dogs (Otitis Interna)
- Eosinophilic Muscle Inflammation in Dogs (Eosinophilic Myositis)
- Dysautonomia in Dogs (Key-Gaskell Syndrome)
- Eye and Facial Nerve Disorder in Dogs (Horner Syndrome)
- Medical Condition in Dogs (Ceruminous Gland Tumors)
Basics and possible causes
The third eyelid, also called the nictitating membrane, is a thin membrane in the inner corner of a dog’s eye that has a protective function. It helps protect the eye from foreign bodies, distributes tear fluid evenly, and can protrude in the event of injury or irritation.
Prolapse of the third eyelid can have various causes. A common cause is inflammation or irritation of the eye, which causes the nictitating membrane to protrude to protect the eye. Infections, allergies or foreign bodies can cause irritation.
Another possible cause is so-called “cherry eye,” in which the gland of the third eyelid protrudes. This gland is responsible for producing part of the tear fluid and can become inflamed or loosen, leading to a visible prolapse.
A prolapsed nictitating membrane can also be a symptom of systemic diseases such as dehydration, neurological disorders, or certain infectious diseases. Sometimes the prolapse occurs in connection with other eye diseases such as corneal ulcers or conjunctivitis.
Typical accompanying symptoms
- A visible pink to reddish tissue that partially or completely covers parts of the eye, often in the inner corner of the eye. This can occur suddenly.
- Increased blinking or winking of the affected eye, which may indicate discomfort or irritation.
- Tearing or discharge from the eye, which can be clear, yellowish, or greenish, depending on the underlying cause.
- Redness or swelling of the eye or surrounding tissues, indicating an inflammatory condition.
- The dog may rub its paw over the eye more often or rub its face on furniture, which is a sign of itching or pain.
- In some cases, there may be reduced vision if the third eyelid partially blocks the field of vision.
When to see a vet?
A visit to the vet is essential if prolapse of the third eyelid occurs suddenly or is accompanied by other symptoms such as heavy discharge, redness, or obvious pain. These signs may indicate a serious infection or injury that requires immediate treatment.
If the dog shows signs of systemic disease such as lethargy, loss of appetite, or Fever, a vet should also be consulted as soon as possible. These symptoms may indicate that the prolapsed nictitating membrane is part of a broader health problem.
Even if the prolapse does not appear immediately threatening, it is advisable to have the situation clarified by a vet in order to determine the underlying cause and start appropriate treatment.
Symptom recognition for the pet owner and veterinary diagnostic procedure
For pet owners, prolapse of the third eyelid is relatively easy to recognize because the tissue that is normally hidden suddenly becomes visible. It is important to monitor the affected eye carefully and watch for additional symptoms such as discharge or redness.
The vet will perform a thorough examination of the eye to determine the cause of the prolapsed nictitating membrane. This may include an examination with a special light source and a magnifying glass to check the eye for foreign bodies, injuries, or signs of infection.
In addition, the vet may perform special tests such as a Schirmer tear test to measure tear production, or fluorescein staining to detect corneal ulcers. In some cases, blood tests or other diagnostic tests may be necessary to rule out systemic diseases.
What the pet owner can do and professional therapy options
Until the veterinary examination, pet owners should try to keep the affected eye clean and avoid further irritation. A soft, damp cloth can be used to gently remove discharge around the eye.
It is important to prevent the dog from rubbing the eye, as this could worsen the problem. A protective collar, also known as an Elizabethan collar, can help protect the eye until veterinary treatment is possible.
Avoid using over-the-counter eye drops or ointments without veterinary advice, as they could worsen the situation or be unsuitable for the underlying cause. The best course of action is to see a vet as soon as possible to get an appropriate diagnosis and treatment.
Outlook on current research
Current research on prolapse of the third eyelid in dogs focuses on various aspects to develop a better understanding and effective treatment options. Scientists are investigating the exact mechanisms that lead to prolapse of the third eyelid. In particular, the role of genetic factors and breed predispositions is being analyzed. Studies show that certain dog breeds such as Cocker Spaniels, Beagles and Basset Hounds have a higher susceptibility to this symptom. Genetic studies aim to identify specific genes associated with this susceptibility. These findings could support targeted breeding programs in the future to minimize the risk.
Another focus of research is the development and evaluation of new treatment methods. Traditionally, surgery has been regarded as the standard treatment to return the third eyelid to its normal position. However, there is a growing number of studies looking at conservative treatments such as special eye medications and therapeutic massage. These approaches could be less invasive and more suitable for certain cases. The effectiveness and long-term stability of such treatments are being studied to determine whether they are a viable alternative to surgery.
The role of environmental factors is also being investigated to understand how external influences can affect the occurrence of a prolapsed nictitating membrane. Researchers are analyzing whether environmental conditions such as air pollution or allergens increase the risk or worsen symptoms. Such information could lead to preventive measures that reduce the occurrence of this symptom. In addition, innovative diagnostic methods are being tested to enable early detection. Advances in imaging technology and molecular diagnostics could enable more accurate and less invasive diagnosis.
Overall, research aims to provide more comprehensive information on the causes and best treatment approaches for prolapse of the third eyelid in dogs. By integrating genetic, therapeutic and environmental findings, scientists hope to sustainably improve the quality of life of affected dogs.