Acanthamoeba Keratitis(1) usually occurs in patients that wear soft contacts and do not use sterile solutions to clean the lens or are exposed to water harboring the organism. Advanced stages have the ring infiltrate of opacification. The infection is usually extremely painful. Cultures must be performed on non-nutrient blood agar layered with E. coli. The histopathology (1,2) may show the star shaped cyst as shown here. Cysts and trophozoites may be present. A granulomatous reaction may also be seen. Back to Cornea