Definition of Interstitial keratitis:

Interstitial keratitis is the 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 transparency (clarity) of the cornea. This condition is often caused by infections and may cause severe visual problems.

Syphilis is the most common cause of interstitial keratitis, but rare causes include leprosy and tuberculosis. Most cases in the developed world occur in patients with fully established syphilis.

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