Home » Diseases » In dogs » Persistent Pupillary Membrane, PPM

Persistent Pupillary Membrane, PPM in Dogs

Occurrence: very rare
Location of disease: Head/Neck

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Home care monitor at home and contact your vet if worse

If the condition worsens / symptoms persist, consult a veterinarian.

Definition

PersistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. pupillary membrane (PPM) is a congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. eye anomalyAn anomaly is a deviation from what is considered normal or expected. In medicine, it often refers to unusual physical or genetic characteristics that may be present at birth or develop later. in dogs in which remnants of the embryonic blood vessel membrane persist in the pupil and can impair vision.

The most important facts at a glance

Persistent pupillary membrane (PPM) is a condition in dogs where tissue remnants of the embryonic pupillary membrane persist and can impair vision. This membrane supplies the eye with nutrients during development and should dissolve before or shortly after birth. Causes of PPM are not fully understood, but genetic factors and developmental disorders play a role. Certain breeds are more commonly affected, but PPM can also occur sporadically. Typical symptoms include thread-like structures in the eye, lens clouding, and impaired vision. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through an eye exam, sometimes supplemented by special tests or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow.. In mild cases, treatment is often unnecessary, while more severe cases may require surgical intervention. Eye drops or ointments help to reduce inflammatory conditions. Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is important to avoid complications. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. varies depending on severity and treatment, but many dogs can lead a normal life. Preventively, responsible breeding practices can help minimize the risk. Research focuses on genetic causes, new treatment methods, and environmental factors during pregnancy. Advances in these areas could improve the treatment and management of PPM in the future.

Causes

During a dog’s embryonic development, a blood vessel membrane forms that covers the pupil and supplies the growing eye with nutrients. This membrane should normally regress completely before birth or shortly thereafter so that light can reach the retinaThe retina is the light-sensitive layer at the back of the eye that captures visual information and transmits it to the brain via the optic nerve. Retinal diseases can lead to vision loss in dogs and cats. unhindered. In dogs with PPM, however, parts of this membrane remain.

PPM occurs in various dog breeds and can be genetic. Breeds such as the Basenji, Mastiff, Chow Chow, and Pembroke Welsh Corgi show a higher prevalence, indicating a hereditary component. Nevertheless, PPM can also occur sporadically in other breeds and is not exclusively due to genetic causes.

The exact reason why the membrane does not completely disappear in some dogs is not fully understood. It is suspected that developmental disorders during embryonic development as well as genetic factors play a role. Environmental factors affecting the fetusThe fetus is a developmental stage of a mammal in the womb that follows after it has passed through the embryonic phase. In humans, the term fetus is used from the 9th week of pregnancy until birth. during pregnancy could also contribute to the development of PPM, although the influence of these factors has been insufficiently researched so far.

Symptoms

Very common symptoms:

Common symptoms:

Lenticular Opacity (Cataract)

Symptoms of PPM can vary depending on how much of the membrane remains and where it is located. In mild cases, symptoms are often inconspicuous and hardly affect the dog’s vision. In more severe cases, clouding of the lens or cornea can occur, which can significantly impair vision.

A common symptom is the presence of thin, thread-like structures in the eye that run from the irisThe iris is the colored part of the eye that surrounds the pupil. It consists of muscle tissue and adjusts the size of the pupil through its contraction or relaxation to regulate the amount of light that enters the eye. to the lens or cornea. These structures are often clearly visible during a veterinary examination. In severely affected dogs, other eye conditions such as cataracts or corneal ulcers may occur, further restricting vision.

In some cases, PPM can lead to increased sensitivity to light or eye irritation, which is noticeable through frequent blinking or tearing. Dog owners should watch for such signs and consult a vet if PPM is suspected.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of PPM is usually made through a thorough ophthalmological examination, where a vet examines the inside of the eye using special instruments. An ophthalmoscope is often used to look closely at the structure of the eyes and confirm the presence of the thread-like structures.

In addition to visual inspection, the vet may perform special tests to assess the impact of PPM on the dog’s vision. These tests may include measuring the pupil’s light response or examining the fundus of the eye. In some cases, an ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. of the eye may also be performed to determine the exact location and extent of the membrane remnants.

Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is important to prevent possible complications and initiate appropriate treatment measures. Therefore, dogs should be examined by a vet regularly, especially if they belong to a breed prone to PPM.

Therapy

Treatment for PPM depends on the severity of the condition and the associated symptoms. In many cases, especially if the membrane remnants are small and do not significantly affect vision, no specific treatment is required. The vet may recommend monitoring the condition regularly to ensure no complications arise.

In more severe cases where vision is impaired or additional eye conditions such as cataracts or corneal ulcers are present, surgical removal of the membrane remnants may be necessary. However, these procedures are complex and should be performed by a specialized veterinary ophthalmologist.

In addition to surgical treatment, eye drops or ointments may be prescribed to reduce inflammatory conditions and support eye health. It is important to follow the vet’s instructions exactly and perform regular check-ups to monitor the success of the treatment.

Prognosis and follow-up care

The prognosis for dogs with PPM largely depends on the severity of the condition and the effectiveness of the treatment. In many cases, especially if the membrane remnants are small and do not affect vision, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good, and the dogs can lead a normal, healthy life.

For dogs with more severe cases or additional eye conditions, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. can vary. Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment are crucial to prevent the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease and preserve vision. In some cases, a complete cure can be achieved through surgery, while in other cases, a permanent visual impairment may remain.

Regular veterinary examinations and careful monitoring of the dog’s condition are important to avoid complications and maintain the dog’s quality of life.

Prevention

Since PPM is a congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. condition, there are limited options for preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring.. An important measure is to promote responsible breeding practices and exclude dogs with known genetic predispositions for PPM from breeding. Breeders should be aware of the genetic risks and perform appropriate health screenings to minimize the risk of passing on the condition.

Furthermore, the health of the pregnant bitch can be supported through optimal care and nutrition during pregnancy to minimize developmental disorders in the fetusThe fetus is a developmental stage of a mammal in the womb that follows after it has passed through the embryonic phase. In humans, the term fetus is used from the 9th week of pregnancy until birth.. While this may not specifically prevent PPM, it contributes to the overall health and development of the puppies.

It is important for dog owners to watch for signs of eye disease in their dogs and see a vet if PPM is suspected. Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and regular eye exams can help avoid potential complications and improve the dog’s quality of life.

Outlook on current research

Persistent pupillary membrane (PPM) is a developmental anomalyAn anomaly is a deviation from what is considered normal or expected. In medicine, it often refers to unusual physical or genetic characteristics that may be present at birth or develop later. that occurs in dogs and is characterized by the presence of tissue remnants in the pupil. These remnants come from the embryonic pupillary membrane, which is normally resorbed after birth. PPM can range from small, harmless tissue remnants to pronounced membranes that can impair vision.

Current research aims to identify the genetic basis of this anomalyAn anomaly is a deviation from what is considered normal or expected. In medicine, it often refers to unusual physical or genetic characteristics that may be present at birth or develop later.. Scientists have made progress by identifying certain genetic markers and mutations associated with PPM. These discoveries could enable genetic testing in the future to identify at-risk dogs and support breeding decisions.

Another focus of the research is on the development of new treatment methods. While mild cases of PPM require no treatment, more severe cases can impair vision and require surgical intervention. Researchers are investigating minimally invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. techniques and improved surgical approaches to optimize treatment outcomes and minimize the risk of complications.

Additionally, the extent to which environmental factors during pregnancy may contribute to the development of PPM is being investigated. Studies on laboratory animals and epidemiological investigations in dogs are being conducted to identify possible external factors that could increase the risk of PPM. This research could provide valuable information for developing preventive measures.

Another area of research is investigating the effects of PPM on the long-term well-being of affected dogs. While many dogs with PPM lead normal lives, the long-term effects on eyesight and overall well-being in more severe cases are not yet fully understood. Long-term studies could help to better understand the quality of life and the necessary management strategies for affected dogs.

Research on persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. pupillary membrane is a dynamic and evolving field. As new technologies and genetic tools are developed, researchers expect significant progress to be made in the coming years. These advances could not only improve the understanding of PPM but also revolutionize the treatment and management of this condition.

Frequently asked questions (FAQs)

What is Persistent Pupillary Membrane (PPM)?

Persistent pupillary membrane is a developmental disorder in which tissue remnants from the embryonic phase remain in the pupil. Normally, these membranes disappear after birth, but with PPM they persist and can impair vision. -

How is PPM diagnosed in dogs?

PPM is usually diagnosed during an eye examination by a vet. The vet can use special instruments to examine the eye closely and determine if tissue remnants are present. -

Can all dog breeds be affected by PPM?

Yes, PPM can occur in all dog breeds, but some breeds tend to be more frequently affected. These breeds include Basenjis, Chow Chows, and Pembroke Welsh Corgis. -

What symptoms can occur in dogs with PPM?

Many dogs with PPM show no obvious symptoms. In more severe cases, however, visual disturbances can occur, which may be noticeable through behavioral changes or difficulty navigating the environment. -

Is PPM painful for the dog?

PPM is usually not painful. The tissue remnants do not normally cause pain unless they lead to other complications such as inflammatory conditions or ulcers. -

How is PPM treated?

Mild cases of PPM usually do not require treatment. In more severe cases that affect vision, surgical removal of the membranes may be necessary. The decision to treat depends on the severity of the symptoms and the impact on the dog's well-being. -

Can PPM be prevented?

There are currently no known methods to completely prevent PPM. Since genetic factors play a role, responsible breeding can help reduce the risk. Breeders can use genetic tests to identify dogs with an increased risk. -

Does PPM affect a dog's quality of life?

In most cases, PPM has no significant impact on a dog's quality of life. Dogs with mild cases of PPM often lead normal lives. In more severe cases that affect vision, adjustments may be necessary to ensure the dog's well-being. -

Is PPM heritable in dogs?

Yes, PPM has a genetic component and can be inherited. That is why it is important to watch for signs of PPM when breeding dogs and to consider genetic testing if necessary. -

Are PPM and cataracts the same thing?

No, PPM and cataracts are different conditions. PPM is the presence of embryonic tissue remnants in the pupil, while cataracts are clouding of the lens. Both can impair vision, but they have different causes and treatment methods.