Interstitial keratitis (IK) is an inflammatory condition causing inflammation in the corneal and anterior segment of the eye. This inflammation will cause deep corneal neovascularization. Patients with IK tend to present in the first to second decade of life. If it is the first presentation of IK, it will be associated with ocular pain, redness, photophobia, and often reduced vision. Once a patient has suffered from an episode of IK, the scarring and corneal neovascularization will remain. The most common etiology of IK is syphilis
. Many times the syphilis is congenital
and will affect both eyes (though not always at the same time). If the syphilitic IK is acquired, it is more likely to affect only one eye. Other common conditions causing IK include herpes simplex virus
(HSV), herpes zoster
, Lyme disease
, collagen vascular disease, HLA B-27 associated inflammatory conditions, and Cogan syndrome
(hearing loss, IK, and tinnitus).