Symptoms include tearing, eye pain, blurred vision, and increased sensitivity to bright light in one or both eyes.
Diagnosis is by a doctor's evaluation and blood tests to rule out other diseases.
Doctors treat the underlying infection.
(See also Introduction to Corneal Disorders Introduction to Corneal Disorders The cornea is the clear layer in front of the iris and pupil. It protects the iris and lens and helps focus light on the retina. It is composed of cells, protein, and fluid. The cornea looks... read more .)
An Inside Look at the Eye
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Interstitial keratitis is rare in the United States. Most cases occur in children or adolescents as a complication of congenital syphilis Syphilis in Newborns Syphilis is an infection caused by the bacteria Treponema pallidum. It causes serious problems in infants infected before birth. Syphilis is caused by bacteria. Serious complications... read more 
. Other causes of interstitial keratitis include Cogan syndrome Cogan Syndrome Cogan syndrome is a rare autoimmune disease of the eye that can affect the cornea. Eye pain, decreased vision, increased sensitivity to bright light, and redness of the eye are common symptoms... read more , Lyme disease Lyme Disease Lyme disease is a tick-transmitted infection caused by Borrelia species, primarily by Borrelia burgdorferi and sometimes by Borrelia mayonii in the United States. These... read more 
, Epstein-Barr virus Infectious Mononucleosis Epstein-Barr virus causes a number of diseases, including infectious mononucleosis. The virus is spread through kissing. Symptoms vary, but the most common are extreme fatigue, fever, sore throat... read more 
, acquired syphilis Syphilis Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. Syphilis can occur in three stages of symptoms, separated by periods of apparent good health. It... read more 
, herpes simplex Herpes Simplex Virus (HSV) Infections Herpes simplex virus infection causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips (cold sores), eyes, or genitals. This very contagious viral infection... read more 
, varicella-zoster virus Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactive... read more 
, and tuberculosis Tuberculosis (TB) Tuberculosis is a chronic contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. It usually affects the lungs. Tuberculosis is spread mainly when people breathe... read more 
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Symptoms of Interstitial Keratitis
Interstitial keratitis can affect one or both eyes. People develop tearing, eye ache, blurred vision, and increased sensitivity to bright light. Sometimes with interstitial keratitis due to syphilis, the cornea becomes cloudy and can cause permanent vision loss.
Diagnosis of Interstitial Keratitis
An eye examination
Blood tests
Doctors suspect interstitial keratitis when they see an affected cornea in a person who also has a history of an infection such as syphilis. To examine the cornea, they usually use a slit lamp Slit-Lamp Examination A person who has eye symptoms should be checked by a doctor. However, some eye disorders cause few or no symptoms in their early stages, so the eyes should be checked regularly (every 1 to 2... read more (an instrument that enables doctors to examine the eye under high magnification).
Blood tests and other tests for syphilis, Lyme disease, and the Epstein-Barr virus are also done. People with interstitial keratitis and normal blood tests should be evaluated for Cogan syndrome Cogan Syndrome Cogan syndrome is a rare autoimmune disease of the eye that can affect the cornea. Eye pain, decreased vision, increased sensitivity to bright light, and redness of the eye are common symptoms... read more .
Treatment of Interstitial Keratitis
Corticosteroid eye drops
Interstitial keratitis may resolve with treatment of the underlying infection. Sometimes people are treated with a corticosteroid eye drop to decrease inflammation in the cornea.
