What is a Corneal Ulcer?

A corneal ulcer is an open wound on your cornea, which is the transparent outer layer of your eye. The cornea is responsible for maintaining clear vision, which is why corneal ulcers are a potentially vision-threatening condition. 

If you think you may have a corneal ulcer, see your eye doctor immediately. If left untreated, corneal ulcers can cause permanent scarring and vision loss.

What Are The Symptoms?

Most corneal ulcers are quite painful. Your cornea has the highest concentration of nerve fibers compared to any other part of your body. This means your cornea is incredibly sensitive, which is why ulcers cause so much pain.

Symptoms of corneal ulcers include:

• Significant eye pain
• Light sensitivity
• Inability to keep eyes open from pain and light sensitivity
• Redness of the eye
• Foreign body sensation (feels like sand or eyelash in the eye)
• Tearing
• Blurry vision
• Soreness of the eye
• Swollen eyelids
• Discharge 
• Visible white spot on the cornea

Causes And Risk Factors 

There are infectious and non-infectious (sterile) corneal ulcers. The majority of ulcers come from bacterial infections, but there are several other causes as well.

Infectious Corneal Ulcers

• Bacterial. These are the most common type of infectious corneal ulcers, especially in contact lens users. Contact lenses can trap bacteria, allowing the bacteria to multiply. People who sleep in their contacts, use dirty contacts or reuse old contacts have a higher risk of infectious ulcers. 
• Viral. Herpes simplex virus or herpes zoster virus can cause corneal ulcers. Herpes simplex is the same virus that causes cold sores on the lips. Once you become infected with herpes simplex, the virus stays dormant in your body and can become reactivated. Sun exposure, stress, illness, or trauma can trigger a reactivation, possibly causing a corneal ulcer. 

Herpes zoster is the same virus that causes chickenpox and shingles. After infection, the virus stays dormant in your nerves and may reactivate later on in life. In addition to eye symptoms, herpes zoster can cause painful blisters on the forehead and nose on the same side as the affected eye.

• Fungal. These infections are less common than bacterial infections. They are more likely to occur in humid areas where mold and yeast can multiply. Most people with fungal corneal ulcers have been exposed to plants, such as someone who works in landscaping.
• Parasitic. Acanthamoeba is a type of amoeba that lives in freshwater. Acanthamoeba-related corneal ulcers are rare, but the infection is severe and extremely painful. Some risk factors for Acanthamoeba infection include using contaminated tap water, swimming in ponds or other bodies of freshwater, or poor contact lens hygiene. 

Non-infectious Corneal Ulcers

• Allergic. Certain types of eye allergies, called atopic or vernal keratoconjunctivitis, can cause corneal ulcers. Atopic keratoconjunctivitis usually affects older adults, while vernal keratoconjunctivitis typically affects younger males. These types of eye allergies are rare. People who are prone to hypersensitivity reactions, such as eczema or asthma, are more likely to develop atopic or vernal keratoconjunctivitis.
• Neurotrophic. These ulcers are associated with damage to your corneal nerves. Some conditions that affect corneal sensation include diabetes, chemical burns in the eye, laser eye surgery, over-wearing contact lenses, and overuse of eye drop medications containing preservatives or anesthetic. Without normal sensation, your corneas cannot heal properly and do not produce enough tears, leaving your eyes vulnerable to corneal ulcers.
• Autoimmune. Certain types of corneal ulcers are associated with autoimmune diseases that affect your connective tissue. These diseases include rheumatoid arthritis, granulomatosis with polyangiitis, and relapsing polychondritis. Connective tissue contains a protein called collagen, which is also abundant in your cornea. 

Prevention

Protecting your eyes and maintaining good eye hygiene is essential in reducing your risk for corneal ulcers. Here are some general tips for preventing corneal ulcers, particularly infectious types:

• Wash your hands before touching your eyes.
• Clean your contact lenses properly and always use fresh contact lens solution and a clean case.
• Do not sleep in your contact lenses or use them longer than directed.
• Do not use saliva or water to rewet your contact lenses. Only use products specifically made for contact lenses.
• Remove all eye makeup before sleep and discard old makeup.
• Wear eye protection if you are exposed to dust, dirt, or other particles that can enter your eyes.
• Use lubricating eye drops to moisturize your eyes. This action also flushes germs, allergens, and other debris out of your eyes.

Diagnosis

Your eye doctor can diagnose your corneal ulcer by examining your eyes under a microscope called a slit-lamp. They may instill a yellow dye called fluorescein into your eye. Then, your doctor views your eye with a special blue light. If there is a corneal ulcer, the dye will highlight the affected area. The ulcer will appear to glow under the blue light.

Treatment Options

Treatment for a corneal ulcer focuses on treating the underlying cause of the ulcer. In general, you should not wear your contact lenses or use an eye patch while you have a corneal ulcer. Covering your eye does not help with the healing process. 

If you are experiencing severe eye pain, your eye doctor may prescribe drops that dilate your pupils. These eye drops may provide some pain relief while your eyes are inflamed. In some cases, your eye doctor may add a steroid eye drop to decrease the chances of corneal scarring.

With corneal ulcers, most eye doctors will follow you closely over several days or even weeks, depending on the severity of the ulcer. These visits are essential to see if your condition is improving.

Treatment for Infectious Corneal Ulcers

• Bacterial. The primary treatment for bacterial corneal ulcers is frequent doses of antibiotic eye drops. Most ulcers respond quickly to the medication, but it is important to continue the antibiotic drops as directed even after you start to improve. 
• Viral. Herpes simplex eye infections are treated with antiviral eye drops or oral antiviral medications. Herpes zoster eye infections require oral antiviral drugs. 
• Fungal. Topical antifungal drops treat fungal corneal ulcers. For severe infections, your eye doctor may prescribe oral antifungal medication.
• Parasitic. Therapy includes combination eye drops that are effective against amoebas. Your eye doctor may also scrape the surface layer of your cornea to remove any infected tissue. Acanthamoeba can be difficult to treat, so it is essential to follow your eye doctor’s instructions.

Treatment for Non-infectious Corneal Ulcers

• Allergic. Eye drops such as steroids, antihistamines, or cyclosporine are treatment options for atopic or vernal keratoconjunctivitis. Sometimes, these types of eye allergies do not respond to topical medications. Some patients need allergy shots to manage their symptoms.
• Neurotrophic. Some neurotrophic corneal ulcers can be managed with lubricating ointments and drops. Severe cases may require further medical treatment or surgery to allow the cornea to heal.
• Autoimmune. Systemic immunosuppressants are often necessary to treat the corneal ulcer as well as the underlying autoimmune disease.