Neurotrophic Keratitis

Causes, Symptoms, Diagnosis, and Treatment Options of Neurotrophic Keratitis

Neurotrophic Keratitis (NK) is a rare degenerative disease of the cornea, primarily caused by impaired corneal innervation. The disease can lead to progressive damage to the corneal surface, with significant implications for vision and quality of life.

The cornea – the clear part in the front of the eye – is a unique biological tissue in that it has no blood vessels and is optically clear. The clarity of the cornea is a fundamental aspect of vision; without this clarity, good vision is impossible.

While the cornea lacks blood vessels and mostly obtains its oxygen supply directly from the air, it is very rich in innervation. It is among the most highly innervated tissues in the body, and even minor injuries to the cornea can be terribly painful (e.g. corneal scratch).

Fortunately, the cornea is also the fastest-healing tissue in the body. The ability of the cornea to heal requires special biological signals from the nerves. These signals – neurotrophic molecules – stimulate the cells of the cornea to divide and reform the damaged tissue.

Neurotrophic keratitis is a disorder in which the cornea has lost its nerves.

There are many causes to neurotrophic keratitis, including chronic trauma from dry eyes, chronic inflammation, herpes infection, and even congenital absence of the nerve.

A major medical advance of the past decade has been the development of techniques to reinnervate the cornea. These include both medical (eye drops) and surgical (corneal neurotization).

The eye drops (cenegermin-bkbj, known as Oxervate) are most useful when the denervation is distal and fairly recent, caused by chronic dry eyes. Otherwise, surgery is required.

Causes of Neurotrophic Keratitis

The cornea is among the most highly innervated tissues in the body. Corneal innervation is required for maintaining corneal health, including the unique transparency of corneal tissue.

Neurotrophic keratitis refers to corneal damage in patients with damaged corneal nerves. 

Causes include:

  • Herpes Zoster and Herpes Simplex viruses: These viral infections can damage corneal nerves.
  • Neurological disorders: Conditions like diabetes, multiple sclerosis, or brain tumors can affect the nerves.
  • Surgical procedures: Some brain and eye surgeries can inadvertently damage corneal nerves.
  • Contact lens use: Long-term use can reduce corneal sensitivity.
  • Topical medications: Prolonged use of certain eye drops can impair nerve function.

Symptoms and Diagnosis

Neurotrophic keratitis symptoms vary, often depending on the stage of the disease:

  • Stage 1 (mild): Reduced corneal sensitivity, mild redness, and blurred vision.
  • Stage 2 (moderate): Persistent epithelial defects, moderate pain, and increased tearing.
  • Stage 3 (severe): Corneal ulcers, significant vision loss, and potential scarring.

Early diagnosis is crucial. It typically involves:

  • Patient history: Assessing previous eye conditions, surgeries, and systemic diseases.
  • Slit-lamp examination: Detailed inspection of the corneal surface.
  • Corneal sensitivity test: Evaluating the sensitivity of the cornea to touch using a Cochet-Bonnet Aesthesiometer.
  • Fluorescein staining: Highlighting defects in the corneal epithelium.
  • Confocal microscopy: Imaging to assess corneal nerves.

Treatment Options

Treatment strategies focus on promoting healing, protecting the cornea, and preventing progression:

  • Artificial tears and ointments: To keep the eye lubricated and protect the corneal surface.
  • Therapeutic contact lenses: To shield the cornea and retain moisture.
  • Antibiotic eye drops: To prevent secondary bacterial infections.
  • Serum eye drops: Containing growth factors and nutrients to promote healing.
  • Neurotrophic factors: Eye drops that contain nerve growth factors.
  • Surgical options: Surgeons in our practice are pioneers in the field of corneal neurotization surgery. In this surgery, a new nerve is created to innervate the cornea. Growth of new nerves takes 6-12 months following the surgery.

Neurotrophic Keratitis presents a significant challenge due to its potential to impair vision severely.

While traditional treatments focus on symptom management and protecting the cornea, surgery to restore corneal innervation and epithelial homeostasis is necessary to treat the underlying cause.

At Kahana Oculoplastic and Orbital Surgery, we offer a full range of treatments, including corneal neurotization surgery. We work closely with Cornea specialists on tailoring treatment.

Many patients have seen their corneas stabilize and their vision improve following treatment. In patients with corneal scarring related to neurotrophic keratitis, corneal neurotization can allow them to become candidates for corneal transplant surgery that can restore corneal clarity.

Dr. Kahana is the most experienced corneal neurotization surgeon in Michigan and among the most experienced in the world, modifying the technique to improve outcomes.

 

 

Great doctor and great person. He truly cares about the patient and will not rush when evaluating your situation. When he says that he treats the patient with the consideration that he would give his own family, he truly means it.
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