Definition of Interstitial keratitis:

Interstitial keratitis is inflammation of the tissue of the cornea, the clear window on the front of the eye. The condition can lead to vision loss.

Causes, incidence, and risk factors:

Interstitial keratitis is a serious condition in which blood vessels grow into the cornea. Such growth can cause loss of the normal clearness of the cornea. This condition is often caused by infections.

Syphilis is the most common cause of interstitial keratitis, but rare causes include:

• Autoimmune diseases, like rheumatoid arthritis and sarcoidosis
• Leprosy
• Lyme disease
• Tuberculosis

In the United States, most cases of syphilis are recognized and treated before this eye condition develops. However, interstitial keratitis remains the most common cause of blindness in the world.