The nictitating membrane is the third eyelid that many animals have. The small skin fold protects the eye from dirt and foreign bodies, the associated gland supplies the eye with tear fluid. Normally, the skin is hardly noticeable – this is different when there is a so-called nictitating skin prolapse, which restricts the animal’s vision and often has to be treated surgically.
The Most Important Things Summarized
- You can immediately recognize a changed nictitating membrane in your pet because a reddish structure suddenly pushes itself from the inside of the eye into the eye. This can occur unilaterally or bilaterally.
- If the nictitating prolapse persists, there is a risk of secondary diseases, so you should definitely consult a veterinarian. Appropriate treatment can then be initiated.
- While a prolapsed nictitating membrane in dogs is usually treated surgically, in cats the causes are more often due to other diseases, so medical treatment can be sufficient.
What is a Nictitating Prolapse?
An enlargement of the nictitating gland is referred to as a prolapsed nictitating skin or nictitating gland prolapse. The nictitating membrane is the third eyelid next to the upper and lower eyelids, which is located in the inner corner of the eye and is supported by cartilage. There is also a tear gland, the so-called nictitating gland. In a prolapsed nictitating gland, this gland protrudes beyond the edge of the eyelid. This phenomenon is also known under the terms nictitating gland hypertrophy, nictitating gland hyperplasia, or cherry eye.
You can visually recognize such an incident by a reddish structure that protrudes into the eye. After some time, redness or even inflammation of the gland and conjunctiva can form. If the incident lasts longer, the production of tear fluid decreases, and the eye becomes chronically dry.
But: A change in the nictitating membrane is not always a sign of abnormality. Even when the animals are asleep, the nictitating membrane can sometimes be clearly seen – but recedes immediately when they wake up.
The Nictitating Membrane Prolapse in the Dog
In dogs, nictitating prolapses are more common in young dogs and short-nosed breeds. Although the cause is not always clear, treatment is usually only possible with surgery.
Causes of nictitating membrane prolapse
What causes a nictitating membrane prolapse has not yet been fully clarified. However, it is assumed that the disease is genetic, especially in short-nosed dog breeds. It is particularly common
- American Cocker Spaniel
- English bulldog
- Lhasa Apso
Most animals are younger than two years when the nictitating membrane prolapse occurs. In older animals, the cause is often a dry eye or a tumor. It is not just the gland that can cause a prolapsed nictitating membrane – it can also be caused by a collapsed nuclear cartilage. This is especially the case with young dogs. Here, too, only an operation can usually help.
Other possible causes are neurological diseases such as ear or throat infections and injuries to the thoracic spine, which lead to impairment of the nerve tracts. But sometimes there is simply no rational explanation and a hazing incident happens out of the blue.
Symptoms in Dogs
The red structure protruding into the eye means that your dog can no longer see properly. In addition, the eye often waters, so that the result is a squinting of the eyes. Sometimes it is also itchy, so the dog scratches its eye. If the incident lasts for a long period of time, the eye usually dries out.
Treatment of nictitating membrane prolapse in dogs
The symptoms are usually clear, making it easy for a vet to diagnose them. Especially in older dogs, it makes sense to examine the eye for possible tumors.
Surgery is usually required to treat it. Pure drug treatment, however, is not enough. Two small incisions are made and the nictitating membrane is sewn into its original position. During the healing phase, eye ointments containing antibiotics and a neck brace are recommended so that the dog cannot scratch its eyes.
Whether another incident can be expected after an operation depends on how serious it was. The chances are good for minor and medium-sized incidents, but for a major incident, a new one can develop. To prevent the dry eye from developing, it is important not to completely remove the gland.
Nicking Skin Prolapse in the Cat
A prolapsed nictitating membrane can also occur in cats, although this is rarer. The British Shorthair, Persian, and other pedigree cats are particularly affected. The causes can usually be determined on the basis of the accompanying symptoms that also occur.
- as a side effect of cat colds, a prolapsed nictitating membrane is often accompanied by a strong discharge from the eyes or nose
- Parasitic infestations, dehydration from conditions such as diarrhea, and vomiting can also cause a nictitating membrane prolapse.
- In the so-called Haw syndrome, there is a bilateral incident without any other symptoms. The suspected causes here are toxins from endoparasites (e.g. tapeworms) and endotoxins in connection with a gastrointestinal disorder.
In addition, allergies, trauma, or injuries to the eye can cause a nictitating membrane prolapse. As in dogs, prolapses of the nictitating gland or a tumor are possible causes.
Different positions of the eyeball must also be distinguished. Animals with a reduced eyeball tend to prolapse, while if the eyeball sinks in at the same time, muscle atrophy or the so-called Horner syndrome can also trigger the nictitating membrane prolapse.
The nictitating skin prolapse in the cat does not go away
The causes of a prolapsed nictitating membrane in a cat can be varied. It is imperative that you visit a veterinarian who will diagnose and recommend the appropriate treatment. If despite this, the nictitating skin prolapse does not go away after 2-3 weeks, further tests in the laboratory are advisable in any case.