What Causes Keratitis in the Eye?

Reviewed on 7/21/2022
A man with a red eye caused by keratitis
There are many causes of keratitis (corneal ulcer) in the eye, which can include bacteria, viruses, parasites, fungi, vitamin A deficiency, improper contact lens use, contaminated water, eye injury, foreign body in the eye, dryness or inflammation of the cornea, allergies, and others.

Keratitis, also called a corneal ulcer, is inflammation and irritation of the cornea often caused by an infection.

Causes of keratitis in the eye include:

  • Infectious keratitis
  • Noninfectious keratitis 
    • Eye injury
      • Such as a scratch on the cornea
    • Foreign body in the eye
    • Dryness or inflammation of the cornea
    • Allergies
    • Overexposure to ultraviolet light (called photo keratitis)
    • Improper contact lens use, such as wearing them for too long or wearing them while swimming 
    • Living in a warm climate, which increases the risk of plant materials damaging the cornea
    • A weakened immune system

What Are Symptoms of Keratitis in the Eye?

Symptoms of keratitis in the eye include:

  • Eye redness
  • The feeling of something in the eye
  • Pain, which can be mild to severe
  • Tearing
  • Eye discharge
  • Blurred vision
  • Decrease in vision
  • Sensitivity to light
  • In severe cases, the cornea may appear gray or have white to gray areas

Even though keratitis is treatable, it is still the most common cause of corneal blindness through an infection in the U.S.

How Is Keratitis in the Eye Diagnosed?

Eye infections are often diagnosed with a patient’s history and an examination of the eye with an ophthalmoscope, a lighted instrument used to examine the eye. 

Other tests to diagnose eye infection may include: 

  • A special dye called fluorescein to light up and check for damage to the cornea
  • Examination of the eye with a slit lamp
  • Culture of pus or discharge coming from the eye
  • Tissue sample to identify the infection

What Is the Treatment for Keratitis in the Eye?

Treatment for keratitis includes the use of eye drops, which may contain:

Severe cases of infectious keratitis may require oral medications. 

Severe cases of noninfectious keratitis may require a bandage to shield the eye in addition to eye medication.

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Reviewed on 7/21/2022

Image source: iStock Images