Keratitis: Overview

Keratitis is an eye condition in which the cornea—the clear, round dome covering the eye’s iris and pupil—becomes swollen or inflamed, making the eye red and painful. In some cases, keratitis can be serious and affect your vision.

Noninfectious keratitis may develop after a minor injury to the eye, by wearing your contact lenses too long, or by a foreign body entering the eye. Infectious keratitis is caused by bacteria, viruses, fungi, or parasites.

This article discusses the symptoms, causes, diagnosis, and treatment of keratitis. It also addresses ways to prevent it.

Keratitis Symptoms

The first symptom of keratitis is usually redness and pain in the eye. Normally only one eye is affected, but in some cases, the condition can affect both eyes.

The following symptoms are often associated with keratitis:

• Red eye
• Foreign body sensation in the eye
• Eye pain
• Sensitivity to light
• Watery eyes
• Blurred vision
• Decrease in vision

What Is the Main Cause of Keratitis?

Keratitis is classified into two types: infectious or noninfectious. The cause of the keratitis determines its type.

Noninfectious

The following conditions may lead to noninfectious keratitis:

• Wearing contact lenses for too long
• Injury to the cornea, such as a scratch
• Not cleaning contact lenses properly
• Wearing your contacts while swimming in a pool or lake
• Foreign body in the eye
• A weakened immune system
• Overexposure to ultraviolet light
• Allergies
• Dryness or inflammation of the cornea

Infectious

The following can lead to infectious keratitis:

• Bacteria: Two types of bacteria that can cause infectious keratitis are Pseudomonas aeruginosa and Staphylococcus aureus. Both of these bacterial infections are usually seen with improper contact lens use.
• Fungi: Fungal keratitis is also often seen in conjunction with improper use of contact lenses. Fungal keratitis can be caused by Aspergillus, Candida, or Fusarium.
• Parasites: A particularly dangerous form of infectious keratitis is called Acanthamoeba keratitis. This type of infection is usually acquired while wearing contact lenses while swimming in a lake.
• Viruses: Viral keratitis is usually caused by the herpes simplex virus. This type progresses from a case of conjunctivitis to infectious keratitis.

Diagnosing Keratitis

Your healthcare provider will examine your eyes and discuss the symptoms you are experiencing. It may be difficult to open your eye if you have an active infection, but your healthcare provider will be able to help you.

A complete eye examination may not be necessary. Your healthcare provider will use a slit lamp to get an excellent view of the inside of your eye. A special stain may be used in order to see any damage that may have already been caused to the internal structures of your eye. A slit lamp can also help your healthcare provider identify irregularities or ulcers of the cornea.

If your healthcare provider suspects an infection, lab testing may be needed. A sample obtained from your eye can help identify what has caused the infection. A vision test may also be performed to make sure vision loss has not occurred.

If dry eye syndrome may be causing your keratitis symptoms, your healthcare provider will perform the Schirmer tear test. A small strip of paper will be inserted into the corner of your eye to measure moisture.

Once a proper diagnosis has been made, your treatment can begin.

How Is Keratitis Treated?

Treatment of keratitis depends on the cause of the condition. Noninfectious keratitis, such as a corneal scratch or other injury, may not require any treatment. Your healthcare provider may prescribe an antibiotic or prescription pain medication if you are in significant pain, and in order to speed healing. In some cases, a protective eye patch may be worn to protect the eye during healing.

If your healthcare provider confirms dry eye syndrome, your treatment will focus on moisturizing your eyes to relieve symptoms. In most cases, moisture is improved by the use of artificial tears and lubricating ointments.

Treatment of infectious keratitis will focus on controlling the underlying cause of the infection.

• Bacterial keratitis: Your healthcare provider will prescribe antibacterial eye drops for mild cases of bacterial keratitis. Oral antibiotics may be needed for severe cases.
• Fungal keratitis: Oral antifungal medication and antifungal eye drops will be prescribed.
• Viral keratitis: Your healthcare provider will try antiviral eye drops and oral antiviral medications. In some cases, the virus may be stubborn and reoccur, requiring more treatment.
• Acanthamoeba keratitis: Your healthcare provider will be aggressive with this serious condition, as vision loss is a possibility. Antiseptic eye drops will be prescribed.

Some cases of infectious keratitis are resistant to many forms of medication. If your eye is permanently damaged, your healthcare provider may recommend having a corneal transplant.

Coping and Prevention

If your eye suddenly becomes red and inflamed, promptly remove your contact lenses if you wear them. Try not to touch or rub your eyes. Lubricating eye drops can help ease the symptoms of keratitis.

Many forms of keratitis can be prevented by following good hygiene habits, especially if you wear contact lenses daily. Be sure to follow your healthcare provider's advice about wearing, cleaning, and storing your contact lenses. Other tips include the following:

• Always wash your hands before handling your contacts.
• Do not sleep in lenses unless recommended by a doctor of optometry.
• Do not swim in contact lenses.
• If you experience redness, pain, or blurry vision, remove the contact lenses immediately.

Summary

Keratitis is an inflammation and swelling of the cornea, the clear front cover of the eye. It is diagnosed by your healthcare provider with an eye exam and using a slit lamp. Treatment will depend on the cause of keratitis and may include pain relievers, lubricating drops, or prescription drugs and medicated eye drops.

If you think you have keratitis, see your healthcare provider right away to avoid serious complications that can cause permanent eye damage.