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

Cornea nigra, also known as black corneal necrosis 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 that manifests as dark spots on the cornea. It commonly occurs in breeds with short faces such as Persians and Himalayan cats. The exact cause is unclear, but chronic irritation, mechanical stress, and possibly insufficient tear production play a role. Symptoms include black spots on the cornea, increased tearing, and potentially corneal ulcers.

Diagnosis is made by a thorough eye examination with a slit lamp microscope and fluorescein staining to detect damage. Treatment often involves surgical removal of the sequestrum, followed by drug therapy to support healing. In mild cases, conservative treatment with artificial tears may be sufficient. The prognosis 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 prevention methods, including genetic studies and new surgical techniques. Early diagnosis 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 epithelium, stroma, and Descemet’s membrane. Cornea nigra affects the stroma, where necrotic tissue accumulates, forming the characteristic black spots.

Cornea nigra occurs mainly in breeds with brachycephalic features, such as Persians and Himalayan cats, although other breeds may also be affected. These breeds often have flat faces and protruding eyes, making them susceptible to injuries and chronic irritation.

The exact causes of black corneal necrosis are not fully understood. It is believed that a combination of chronic irritation, mechanical stress, and possibly insufficient tear production plays a role. Injuries, eye infections, and genetic predispositions may also contribute.

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

Symptoms

Very common symptoms:

Common symptoms:

The most noticeable 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 be of varying sizes. They are usually sharply defined and may increase in size 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 an attempt by the eye to cleanse itself.

In addition to the obvious spots, cats may also show decreased vision in the affected eye, especially if the sequestrum is large or affects the central visual axis. In severe cases, an ulcer may develop if the cornea is weakened by the necrotic processes.

Diagnosis

The diagnosis of Cornea nigra is usually made by a thorough ophthalmological examination. The veterinarian will examine the eye with a special instrument, the slit lamp 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 staining 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 to identify areas where the corneal barrier is damaged.

In some cases, an ultrasound examination of the eye may be performed to assess the posterior structures of the eye and rule out other conditions that may affect the cornea. A thorough history and discussion of the symptoms and breed of the cat can also provide valuable clues.

Therapy

Treatment of Cornea nigra often requires surgical intervention, especially if the sequestrum is large or causes significant discomfort. The most common method is keratectomy, in which the sequestrum and surrounding necrotic tissue are removed. This surgery is performed under general anesthesia and requires skill and experience to avoid further damage to the cornea.

After surgery, drug therapy may be necessary to support healing and prevent infection. This often includes antibiotic eye drops or ointments, as well as pain relievers to improve the cat’s well-being.

In some cases, especially if the sequestrum is small or does not cause major discomfort, conservative treatment may be chosen. This often involves the use 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 full recovery 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 postoperative care and regular follow-up examinations are crucial for successful healing.

In cats predisposed to this condition, repeated episodes may occur, and it is important to identify and treat the underlying causes, such as chronic irritation or insufficient 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 examinations. Especially in breeds such as 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. Be sure to keep your cat’s eyes clean and free of dirt or debris. If your cat is prone to watery eyes, gently cleaning them with a soft, damp cloth can help prevent irritation.

A balanced diet rich in essential vitamins and nutrients supports your cat’s overall health and can strengthen the immune system, which in turn can help prevent eye problems. Make sure your cat’s environment is safe to avoid injuries or trauma to the eyes.

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

Outlook on current research

Cornea nigra, or black corneal necrosis, is an eye disease that occurs primarily in 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 chronic irritations of the cornea can lead to necrosis, with certain breeds such as Persian cats being particularly susceptible. Genetic predisposition plays an important role, and researchers are currently investigating which genes in the affected breeds are responsible for the susceptibility.

Another important area of research is the prevention and improvement of treatment. Scientists are working to find effective methods to protect the cornea and promote healing. This involves exploring the use of drugs that reduce inflammatory conditions and support the regeneration of the cornea. The role of nutrition 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 use 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.

In the long term, the goal of research is to develop early diagnosis 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 genomics and the development of biomarkers could bring decisive breakthroughs here.

In summary, research on Cornea nigra in cats is on a good path, but there are still many questions 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 necrosis, i.e. the death of corneal tissue.
Which cats are most often affected? Particularly susceptible are breeds with a flat face such as Persian cats and Exotic Shorthairs. These breeds have a higher tendency to eye problems due to their facial structure.
What are the causes of the disease? The exact cause is not fully understood, but mechanical stimuli, chronic irritations, 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 diagnosis is usually made by a thorough eye examination by a veterinarian, which includes slit lamp 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 therapy based on the severity of the disease.
Can the disease be cured? A complete cure is not always possible, but the symptoms can be significantly improved with appropriate treatments. Early diagnosis significantly improves the chances of success.
How can I prevent it? Regular eye examinations and good care of the eyes can reduce the risk. In susceptible breeds, special attention should be paid to signs of eye irritation.
What complications can occur? Without treatment, it can lead to a deterioration of vision or even loss of the eye. Chronic 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 drug and surgical approaches as well as genetic factors to develop better diagnostic and treatment methods. These advances could significantly improve treatment outcomes in the future.