Neurotrophic keratitis (NK) is a rare condition that affects the surface of your eye. It happens when the cornea (the clear front part of your eye) loses some or all of its ability to feel.
That loss of sensation may sound like a relief if you’re dealing with chronic eye pain, but it actually makes healing much harder. NK can quietly damage your vision without causing much discomfort, which is why getting diagnosed early is so important.
In this guide, we’ll explain what causes NK, how it’s diagnosed, what treatment options are available, and how you can protect your eyes going forward.
Why are Corneal Nerves Important?
Corneal nerves play a big role in keeping your eye healthy. They help your eye respond to irritants, stay lubricated, and heal after injury.
When those nerves are damaged, your eye may not blink enough or produce enough tears—two things that protect your eye and support healing. Over time, this lack of sensation can cause dry spots, slow healing, and even lead to wounds on the eye’s surface.
In NK, these changes may happen gradually, and without pain as a warning sign. That’s why even mild vision changes or chronic irritation should be taken seriously.
If you’ve had eye surgery, an eye infection, or a history of nerve issues, your doctor may want to check your eye’s surface sensation as part of your exam.
What Causes Neurotrophic Keratitis?
NK happens when the cornea loses its ability to feel, usually because of nerve damage. Sometimes the problem starts in the eye itself or in nearby tissue. For example:
- Herpetic eye disease. Herpes simplex or shingles (herpes zoster) can damage corneal nerves.
- Eye surgery or injury. Procedures like LASIK, PRK, or trauma to the eye may affect nerve function.
- Chemical or thermal burns. These can disrupt corneal nerve endings.
- Long-term contact lens use. This may reduce oxygen to the eye and irritate nerve endings.
- Toxic medications. Some preserved eye drops (like those with benzalkonium chloride) can damage nerves over time.
If you’ve had any of these, talk with your eye doctor about your risk for NK.
Other times, the issue starts in your body. Conditions that can reduce corneal sensation include:
- Diabetes. High blood sugar can damage nerves over time.
- Neurologic diseases. Multiple sclerosis and similar conditions may affect the nerves that serve the eyes.
- Rare genetic conditions. These include Riley-Day syndrome and other inherited disorders that impair nerve function.
Even if you haven’t noticed eye symptoms, your overall health may play a role in how your eyes feel and heal.
Symptoms and Red Flags for Neurotrophic Keratitis
NK doesn’t always cause obvious symptoms, especially in early stages. You might think your eye is dry, slightly irritated, or just “off.”
Some of the early signs include:
- Mild stinging or burning
- Fluctuating vision
- A gritty or foreign body sensation
- Light sensitivity
- Discomfort when wearing contacts
But here’s the tricky part: because the cornea can’t feel well, these symptoms may be faint even when damage is present. If you’ve had recent eye surgery, infection, or nerve issues, any of these signs deserve a closer look.
Urgent Signs to Heed
Sometimes, NK progresses without much warning. Watch for these signs that mean it’s time to get care right away:
- Sudden increase in redness or discharge
- New blurry or foggy vision
- A visible white spot on your eye
- Pain that wasn’t there before—or no pain with worsening vision
- Swelling or a change in the shape of your cornea
These may signal a corneal ulcer or thinning that needs urgent treatment. Don’t wait to see if they get better—call your eye doctor or go to urgent care.
Stages of Neurotrophic Keratitis
Doctors classify NK in three stages, based on what they see during your eye exam. This staging helps guide treatment and monitor progress.
Stage One
In the early stage, the surface of your eye may look slightly cloudy or dry. You might have reduced tear production or areas where the tear film breaks up too quickly.
Your doctor may use dyes such as fluorescein or Rose Bengal to highlight small areas of damage on the cornea. You may not feel much discomfort, even though the surface isn’t healing as it should.
Stage Two
At this stage, your eye may develop a persistent epithelial defect—an area where surface cells are missing that won’t heal properly. This is a warning sign that the cornea is struggling to repair itself.
Your physician might see signs such as swelling or folding in the deeper layers of the cornea. The edges of the defect may look smooth and round, which is typical in NK.
Stage Three
This is the most serious stage. Without healing, the cornea can develop an open wound, known as an ulcer. The deeper layer (stroma) may start to thin or “melt,” increasing the risk of corneal perforation—a small hole that can threaten vision.
At this point, urgent care is needed. Treatment typically involves both medication and protective measures to maintain corneal integrity and promote healing.
How Doctors Diagnose NK
Neurotrophic keratitis is diagnosed through a combination of your medical history and specific eye tests. There’s no single test for NK, but your doctor will look for key clues that point to it.
Exam and Stains
Your doctor will examine your eye under magnification (a slit lamp) and may apply special dyes like fluorescein or lissamine green. These help highlight surface damage that’s otherwise hard to see.
You’ll also be asked about previous eye infections, surgeries, injuries, or any history of nerve problems or systemic illness.
Sensation Tests
One of the most important clues is a reduced or absent feeling in your cornea. Your doctor may gently touch the surface of your eye with a soft filament or use a tool called an aesthesiometer to check sensation levels.
In some cases, a specialized imaging technique called confocal microscopy may be used to examine corneal nerves in detail.
Similar Conditions to NK
Several eye conditions can resemble NK but have different causes. These include:
- Dry eye disease
- Exposure keratopathy (when your eyelid doesn’t close fully)
- Infectious keratitis
- Blepharitis (eyelid inflammation)
- Autoimmune conditions like Sjögren’s syndrome
Your doctor may need to rule these out before confirming NK. If you’re not sure what your diagnosis means, don’t hesitate to ask for a clearer explanation.
Neurotrophic Keratitis Treatment by Stage
Treating NK depends on the disease stage. The primary goals are to protect the ocular surface, promote healing, and, when possible, restore nerve function.
Lubrication
In the early stages, treatment often begins with preservative-free artificial tears to maintain surface moisture. Ointments may be used at night for extra protection.
If the eye is very dry or slow to heal, your doctor may recommend autologous serum tears—drops made from your own blood—or other supportive treatments like platelet-rich plasma.
These therapies help mimic natural tear components and promote surface healing.
Biologic Therapies
For more advanced cases, treatments may include:
- Cenegermin (Oxervate). A prescription eye drop that contains a lab-made form of nerve growth factor. It supports nerve repair and promotes ocular healing.
- Topical insulin. Sometimes used to stimulate surface healing.
- RGTA therapy. A gel that mimics heparan sulfate (a natural component of the cornea’s healing matrix).
These medications are usually reserved for moderate-to-severe NK and may require multiple applications per day.
Protective Lenses
Your doctor may fit you with therapeutic soft contact lenses or scleral lenses that cover and protect the eye’s surface while it heals. These lenses also help keep moisture in.
Because lenses carry a small risk of infection, you’ll need careful follow-up and hygiene instructions.
Infection Care
Unlike NK, infectious keratitis is treated with antimicrobial agents (antibiotics, antivirals, or antifungals), depending on the cause. However, the two conditions sometimes overlap, especially if the eye is already compromised.
Your doctor may prescribe fortified antibiotic drops if they’re concerned about infection. But antibiotics aren’t a first-line treatment for NK alone, and overuse can make healing harder.
You should only use antibiotic drops when your provider confirms they’re needed.
Recovery and Self-Care After NK Treatment
Even if your eye feels better, it’s important to keep all follow-up appointments. Your symptoms might not reflect how well your eye is healing, so your doctor will want to check for changes you can’t feel. In many cases, multiple visits are needed to adjust treatment and monitor progress.
Protecting your eyes at home can also support healing. Some basics include:
- Avoid rubbing your eyes
- Use only the drops your doctor recommends
- Take breaks from screens to reduce dryness
- Wear sunglasses outdoors to block UV exposure
- Keep your hands clean before touching your eyes
Let your doctor know if any new symptoms develop, or if your drops cause burning or stinging.
