Iridology is a diagnostic tool used by a wide variety of non-Western healers. Iridology observes changes in texture and color of the iris and correlates them with physical and mental state of health. Iridology is also used to identify dietary deficiencies and accumulation of toxic chemicals in the body.
Originally developed in the 19th century by Ignatz von Peczely, a Hungarian physician, iridology was adapted for modern practice in the 1950s by Bernard Jensen, an American chiropractor. Jensen based his practice on detailed diagrams of the left and right irises. He then assigned every organ, many body parts, and bodily functions to a specific location on one or both irises. Iridologists believe that the degrees of light and darkness in the iris give enormous clues to the body's general health. They also examine textures of fibres in the iris.