Corneal ulcers and infections

Answer 1

Definition

The cornea is the transparent area at the front of the eyeball. A corneal ulcer is an erosion or open sore in the outer layer of the cornea. It is associated with infection.

See also: Corneal injury

Alternative Names

Bacterial keratitis; Fungal keratitis; Acanthamoeba keratitis; Herpes simplex keratitis

Causes, incidence, and risk factors

Corneal ulcers are most commonly caused by an infection with bacteria, viruses, fungi, or parasite. Other causes include:

• Abrasions (scratches)
• Foreign bodies in the eye
• Inadequate eyelid closure
• Severely dry eyes
• Severe allergic eye disease
• Various inflammatory disorders

Contact lens wear, especially soft contact lenses worn overnight, may cause a corneal ulcer. Herpes simplex keratitis is a serious viral infection. It may cause repeated attacks that are triggered by stress, exposure to sunlight, or any condition that impairs the immune system.

Fungal keratitis can occur after a corneal injury involving plant material, or in immunosuppressed people. Acanthamoeba keratitis occurs in contact lens users, especially those who attempt to make their own homemade cleaning solutions.

Risk factors are dry eyes, severe allergies, history of inflammatory disorders, contact lens wear, immunosuppression, trauma, and generalized infection.

Symptoms

• Eye burning, itching and discharge
• Eye pain
• Eye redness
• Impaired vision
• Sensitivity to light (photophobia)
• Watery eyes
• White patch on the cornea

Signs and tests

• Examination of scrapings from the ulcer
• Fluorescein stain of the cornea
• Keratometry (measurement of the cornea)
• Pupillary reflex response
• Refraction test
• Slit-lamp examination
• Tear test
• Visual acuity

Blood tests to check for inflammatory disorders may also be needed.

Treatment

Treating corneal ulcers and infections depends on the cause. They should be treated as soon as possible to prevent further injury to the cornea. Patients usually start treatment with an antibiotic that is effective against many bacteria. More specific antibiotic, antiviral, or antifungal eye drops are prescribed as soon as the cause of the ulcer has been identified.

Corticosteroid eye drops may be used to reduce inflammation in certain conditions. Severe ulcers may need to be treated with corneal transplantation.

Expectations (prognosis)

Untreated, a corneal ulcer or infection can permanently damage the cornea. Untreated corneal ulcers may also perforate the eye (cause holes), resulting in spread of the infection inside, increasing the risk of permanent visual problems.

Complications

• Loss of the eye
• Severe vision loss
• Scars on the cornear

Calling your health care provider

Call your health care provider if you develop impaired vision, severe light sensitivity, or eye pain.

Prevention

Prompt, early attention by an ophthalmologist for an eye infection may prevent ulcers from forming. Wash hands and pay very close attention to cleanliness while handling contact lenses. Avoid wearing contact lenses overnight.

References

Butler FK. The eye in the wilderness. In: Auerbach PS, ed. Wilderness Medicine. 5th ed. St. Louis, Mo: Mosby; 2007:chap 25.

Answer 2

Definition

The cornea is the clear (transparent) tissue at the front of the eye. A corneal ulcer is an erosion or open sore in the outer layer of the cornea. It is often caused by infection.

See also: Corneal injury

Alternative Names

Bacterial keratitis; Fungal keratitis; Acanthamoeba keratitis; Herpes simplex keratitis

Causes, incidence, and risk factors

Corneal ulcers are most commonly caused by an infection with bacteria, viruses, fungi, or a parasite.

• Acanthamoeba keratitis occurs in contact lens users, especially in people who make their own homemade cleaning solutions.
• Fungal keratitis can occur after a corneal injury involving plant material, or in people with a suppressed immune system.
• Herpes simplex keratitis is a serious viral infection. It may cause repeated attacks that are triggered by stress, esposure to sunlight, or any condition that impairs the immune system.

Corneal ulcers or infections may also be caused by:

• Eyelids that do not close all the way, such as with Bell's palsy
• Foreign bodies in the eye
• Scratches (abrasions) on the eye surface
• Severely dry eyes
• Severe allergic eye disease
• Various inflammatory disorders

Contact lens wear, especially soft contact lenses worn overnight, may cause a corneal ulcer.

Symptoms

Symptoms of infection or ulcers of the cornea include:

• Blurry or hazy vision
• Eye that appears red or bloodshot
• Itching and discharge
• Sensitivity to light (photophobia)
• Very painful andwatery eyes
• White patch on the cornea (with herpes)

Signs and tests

• Examination of scrapings from the ulcer
• Fluorescein stain of the cornea
• Keratometry (measurement of the corneal curvature)
• Pupillary reflex response
• Refraction test
• Slit-lamp examination
• Tests for dry eye
• Visual acuity

Blood tests to check for inflammatory disorders may also be needed.

Treatment

Treatment for corneal ulcers and infections depends on the cause. Treatment should be started as soon as possible to prevent scarring of the cornea.

If the exact cause is not known, patients may start treatment with antibiotic drops that work against many kinds of bacteria.

Once the exact cause is known, drops that treat bacteria, herpes, other viruses, or a fungus are prescribed.

Corticosteroid eye drops may be used to reduce swelling and inflammation in certain conditions.

Your doctor may also recommend that you:

• Avoid eye makeup
• Don't wear contact lenses at all, or don't wear them at night
• Take pain medications
• Wear an eye patch to keep light out and help with symptoms
• Wear protective glasses

Severe ulcers may need to be treated with corneal transplantation.

Expectations (prognosis)

Many people recover completely from corneal ulcers or infections, or they have only a minor change in vision.

However, a corneal ulcer or infection can cause long-term damage to the cornea and lead to a noticeable worsening of vision.

Complications

Untreated corneal ulcers and infections may lead to:

• Loss of the eye (rare)
• Severe vision loss
• Scars on the cornea

Calling your health care provider

Call your health care provider if:

• You have symptoms of corneal ulcers or an infection
• You have been diagnosed with this condition and your symptoms become worse after treatment

Prevention

Prompt, early attention by an ophthalmologist for an eye infection may prevent ulcers from forming. Wash hands and pay very close attention to cleanliness while handling contact lenses. Avoid wearing contact lenses overnight.

References

Sharma R, Brunette DD. Ophthalmology. In: Mark JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier;2009:chap 69.

McLeod SD. Bacterial keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier;2008:chap 4.12.

McLeod SD. Fungal keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier;2008:chap 4.13.

Tuli SS. Herpes simplex keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier;2008:chap 4.15.

Soukiasian S. Peripheral ulcerative keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier;2008:chap 4.16.

Bouchard CS. Noninfectious keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier;2008:chap 4.17.

Reviewed By

Review Date: 07/28/2010

Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.