Home » Diseases » In cats » Cornea Nigra, Black Corneal Necrosis (Dark Spots on the Eye, Corneal Sequestrum)

Cornea Nigra, Black Corneal Necrosis (Dark Spots on the Eye, Corneal Sequestrum) in cats

Occurrence: common
Location of illness: Head/Neck

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

When to visit the vet?

Urgent see a veterinarian within 24 hours

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

Definition

Cornea nigra, also known as black corneal necrosisNecrosis is the Death of tissue in a living organism, caused by factors such as injury, infection, or lack of blood supply. Necrotic tissue can cause Inflammatory conditions and further health problems. or corneal sequestrum, is an eye disease in cats characterized by the formation of dark, necrotic spots on the cornea. These spots can lead to discomfort and Visual disturbances and often require surgical treatment to restore normal eye function.

The most important facts at a glance

Cornea nigra, also known as black corneal necrosis, is an eye disease in cats characterized by dark spots on the cornea. It frequently occurs in short-faced breeds like Persians and Himalayan cats. The exact cause is unclear, but chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation, mechanical stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., and possibly insufficient tear production play a role. Symptoms include black spots on the cornea, increased tearing, and potentially corneal ulcers.

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 a thorough eye examination with a slit lampA slit lamp is a special microscope used in veterinary ophthalmology to examine the anterior structures of the eye in detail, including the cornea, the iris, and the lens. Examination with a slit lamp can aid in the diagnosis of eye diseases in dogs and cats. microscope and fluorescein stainingFluorescein staining is a diagnostic technique that uses fluorescein, a fluorescent dye, to make tissues, cells, or microbiological samples visible under a microscope, especially in ophthalmology to detect damage to the cornea. to detect damage. Treatment often involves surgical removal of the sequestrum, followed by medication to support healing. In mild cases, conservative treatment with artificial tears may be sufficient. 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 if the disease is detected and treated early, although there are risks of complications such as infections.

To prevent the disease, regular veterinary check-ups and good eye hygiene are crucial. Research focuses on understanding the causes and developing better treatment and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. methods, including genetic studies and new surgical techniques. 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 personalized therapies could help minimize the risk and impact of the disease in the future.

Causes

The cat’s cornea is a transparent layer that protects the eye and is responsible for clear vision. It consists of several layers, including the EpitheliumEpithelium is a type of tissue that lines the surfaces of the body, as well as internal cavities and ducts. Epithelial tissue serves as a protective barrier, is involved in secretion, and can have sensory functions., the stroma, and Descemet’s membrane. Cornea nigra affects the stroma, where necrotic tissue accumulates, forming the characteristic black spots.

Cornea nigra primarily occurs in breeds with brachycephalic features, such as Persian and Himalayan cats, although other breeds can also be affected. These breeds often have flat faces and protruding eyes, making them susceptible to injuries and chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation.

The exact causes of black corneal necrosisNecrosis is the Death of tissue in a living organism, caused by factors such as injury, infection, or lack of blood supply. Necrotic tissue can cause Inflammatory conditions and further health problems. are not fully understood. It is believed that a combination of chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation, mechanical stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., and possibly insufficient tear production plays a role. Injuries, eye infections, and genetic predispositions could also contribute.

Some theories suggest that repeated microtraumas or constant irritation of the cornea, possibly due to insufficient eyelid closure or tear flow, lead to an accumulation of dead tissue that becomes visible as a sequestrum. Some scientists also suspect that insufficient blood supply to the cornea could play a role.

Symptoms

Very common symptoms:

Common symptoms:

The most striking symptom of cornea nigra is the appearance of one or more dark spots on the cornea. These spots are often brown or black and can vary in size. They are usually sharply defined and can grow larger over time.

Cats with cornea nigra may show signs of Eye pain, including increased blinking, squinting, or closing the affected eye. Increased tear production or eye discharge may also occur, often as the eye’s attempt to clean itself.

In addition to the obvious spots, cats may also show reduced vision in the affected eye, especially if the sequestrum is large or affects the central visual axis. In severe cases, an ulcerAn ulcer is an open wound or erosion of the skin or mucous membrane that often heals poorly and can be caused by a variety of factors, including infections and chronic inflammatory conditions. may develop if the cornea is weakened by the necrotic processes.

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 cornea nigra is usually made through a thorough ophthalmological examination. The veterinarian will examine the eye with a special instrument, the slit lampA slit lamp is a special microscope used in veterinary ophthalmology to examine the anterior structures of the eye in detail, including the cornea, the iris, and the lens. Examination with a slit lamp can aid in the diagnosis of eye diseases in dogs and cats. microscope, to view the condition of the cornea in detail. The dark spots are usually clearly visible, but the doctor will assess the entire structure of the cornea to determine the extent of the problem.

Fluorescein stainingFluorescein staining is a diagnostic technique that uses fluorescein, a fluorescent dye, to make tissues, cells, or microbiological samples visible under a microscope, especially in ophthalmology to detect damage to the cornea. can be used to detect ulcers or other damage to the cornea that may be associated with the presence of a sequestrum. This staining helps identify areas where the corneal barrier is damaged.

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. examination of the eye may be performed to assess the posterior structures of the eye and rule out other conditions that could affect the cornea. A thorough medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and discussion of the cat’s symptoms and breed can also provide valuable clues.

Therapy

The treatment of cornea nigra often requires surgical intervention, especially if the sequestrum is large or causes significant discomfort. The most common method is keratectomy, where the sequestrum and surrounding necrotic tissue are removed. This surgery is performed under general anesthesiaGeneral anesthesia is a medical procedure that induces unconsciousness and eliminates pain during surgical procedures. It involves the use of anesthetics to temporarily shut down the body's overall perception. and requires skill and experience to avoid further damage to the cornea.

After surgery, medication may be necessary to support healing and prevent infections. This often includes antibiotic eye drops or ointments, as well as Pain medication to improve the cat’s well-being.

In some cases, especially if the sequestrum is small or causes no major discomfort, conservative treatment may be chosen. This often involves the application of lubricants or artificial tears to keep the cornea moist, as well as regular check-ups to monitor progress.

Prognosis and follow-up care

The prognosis for cats with cornea nigra is generally good, especially if the condition is detected and treated early. Surgical removal of the sequestrum often leads to a complete restoration of vision and relief of symptoms.

However, there is always a risk of complications, such as infections or scarring, which could permanently impair vision. Careful postoperativePostoperative refers to the time after a surgical operation. This phase includes recovery and the management of possible complications after the procedure. care and regular follow-up examinations are crucial for successful healing.

In cats that have a predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. for this disease, repeated episodes may occur, and it is important to identify and treat the underlying causes, such as chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation or inadequate tear production, to minimize future problems.

Prevention

To reduce the risk of cornea nigra, also known as corneal sequestrum, in cats, it is important to perform regular veterinary check-ups. Especially for breeds like Persian cats or other brachycephalic breeds that are more prone to eye problems, the eyes should be checked regularly.

Good hygiene around the eye area is also crucial. Make sure to keep your cat’s eyes clean and free of dirt or debris. If your cat tends to have watery eyes, gentle cleaning with a soft, damp cloth can help prevent irritation.

A balanced diet rich in essential vitamins and nutrients supports your cat’s general health and can strengthen the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., which in turn can help prevent eye problems. Ensure your cat’s environment is safe to prevent injuries or traumas to the eyes.

At the first signs of an eye problem, such as excessive blinking, redness, or changes in corneal transparency, you should consult a veterinarian immediately. Early intervention can help prevent the development of more serious problems and protect your cat’s eye health long-term.

Outlook on current research

Cornea nigra, or black corneal necrosisNecrosis is the Death of tissue in a living organism, caused by factors such as injury, infection, or lack of blood supply. Necrotic tissue can cause Inflammatory conditions and further health problems., is an eye disease that primarily affects cats and is characterized by the formation of dark spots on the cornea. Current research focuses on better understanding the exact causes and mechanisms of this disease. It is suspected that mechanical stimuli or chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation of the cornea can lead to necrosisNecrosis is the Death of tissue in a living organism, caused by factors such as injury, infection, or lack of blood supply. Necrotic tissue can cause Inflammatory conditions and further health problems., with certain breeds like Persian cats being particularly susceptible. Genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. plays an important role, and researchers are currently investigating which genes in affected breeds are responsible for susceptibility.

Another important area of research is preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. and improvement of treatment. Scientists are working to find effective methods to protect the cornea and promote healing. This involves researching the use of medications that reduce Inflammatory conditions and support corneal regeneration. The role of diet and environmental factors is also being investigated to determine whether certain nutrients or living conditions can reduce the risk of the disease.

In the experimental phase, new surgical techniques are also being tested to repair or replace the cornea. This includes the transplantation of corneal tissue or the application of biomimetic materials that mimic the natural structure and function of the cornea. These approaches are promising but still require extensive studies to confirm their safety and effectiveness.

Long-term, the goal of research is to develop 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 personalized treatment options. This would make it possible to detect the disease at an early stage and offer individually tailored therapies based on the genetic and physiological characteristics of the affected cat. Advances in genomic research and the development of biomarkers could bring crucial breakthroughs here.

In summary, research into cornea nigra in cats is well underway, but many questions still remain to be answered. The findings from current research could not only benefit cats but also improve the general understanding of eye diseases in pets.

Frequently asked questions (FAQs)

What is Cornea nigra? Cornea nigra is an eye disease that occurs in cats and is characterized by dark spots on the cornea. These spots are caused by local necrosisNecrosis is the Death of tissue in a living organism, caused by factors such as injury, infection, or lack of blood supply. Necrotic tissue can cause Inflammatory conditions and further health problems., i.e., the death of corneal tissue.
Which cats are most often affected? Breeds with flat faces, such as Persian cats and Exotic Shorthairs, are particularly susceptible. Due to their facial structure, these breeds have a higher tendency for eye problems.
What are the causes of the disease? The exact cause is not fully understood, but mechanical stimuli, chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. irritation, and genetic factors play a role. Eye injuries and infections can also contribute to the development of the disease.
How is Cornea nigra diagnosed? 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. is usually made through a thorough eye examination by a veterinarian, which includes slit lampA slit lamp is a special microscope used in veterinary ophthalmology to examine the anterior structures of the eye in detail, including the cornea, the iris, and the lens. Examination with a slit lamp can aid in the diagnosis of eye diseases in dogs and cats. microscopy and possibly additional tests to assess the corneal structure.
What treatment options are there? Treatment can range from the use of eye drops to relieve symptoms to surgical procedures to remove the necrotic tissue. The veterinarian will recommend the most appropriate therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. based on the severity of the condition.
Can the disease be cured? Complete healing is not always possible, but symptoms can be significantly improved with appropriate treatments. 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. significantly improves the chances of success.
How can I prevent it? Regular eye examinations and good eye care can reduce the risk. For susceptible breeds, particular attention should be paid to signs of eye irritation.
What complications can occur? Without treatment, vision may worsen or even lead to loss of the eye. ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Pain and Inflammatory conditions are also possible complications.
Is the disease painful for the cat? Yes, cornea nigra can cause Pain and discomfort. Symptoms such as increased blinking, tearing, and light sensitivity indicate Pain.
Are there new developments in research? Yes, research is investigating new medical and surgical approaches, as well as genetic factors, to develop better 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 methods. These advances could significantly improve treatment outcomes in the future.

Frequently asked questions (FAQs)

1. What is Cornea nigra?

Cornea nigra is an eye disease that occurs in cats and is characterized by dark spots on the cornea. These spots are caused by local necrosis, i.e., the death of corneal tissue.

2. Which cats are most often affected?

Breeds with flat faces, such as Persian cats and Exotic Shorthairs, are particularly susceptible. Due to their facial structure, these breeds have a higher tendency for eye problems.

3. What are the causes of the disease?

The exact cause is not fully understood, but mechanical stimuli, chronic irritation, and genetic factors play a role. Eye injuries and infections can also contribute to the development of the disease.

4. How is Cornea nigra diagnosed?

The diagnosis is usually made through a thorough eye examination by a veterinarian, which includes slit lamp microscopy and possibly additional tests to assess the corneal structure.

5. What treatment options are there?

Treatment can range from the use of eye drops to relieve symptoms to surgical procedures to remove the necrotic tissue. The veterinarian will recommend the most appropriate therapy based on the severity of the condition.

6. Can the disease be cured?

Complete healing is not always possible, but symptoms can be significantly improved with appropriate treatments. Early diagnosis significantly improves the chances of success.

7. How can I prevent it?

Regular eye examinations and good eye care can reduce the risk. For susceptible breeds, particular attention should be paid to signs of eye irritation.

8. What complications can occur?

Without treatment, vision may worsen or even lead to loss of the eye. Chronic Pain and Inflammatory conditions are also possible complications.

9. Is the disease painful for the cat?

Yes, cornea nigra can cause Pain and discomfort. Symptoms such as increased blinking, tearing, and light sensitivity indicate Pain.

10. Are there new developments in research?

Yes, research is investigating new medical and surgical approaches, as well as genetic factors, to develop better diagnosis and treatment methods. These advances could significantly improve treatment outcomes in the future.