Iridology, also known as iridodiagnosis, is an alternative medicine practice that examines the patterns, colors, and other characteristics of the iris to know a patient's systemic health.
Derived from the Greek īris ('iris') and logiā ('study')
The practice of examining a person's eyes to help determine their health can be traced back from the ancient Greeks.
The first description of the practice of Iridology (homolaterality) are found in Chiromatica Medica, a famous work published in 1665 and reprinted in 1670 and 1691 by Philippus Meyeus (Philip Meyen von Coburg).
The first use of the word Augendiagnostik (“eye diagnosis,” loosely translated as iridology) began with Ignatz von Péczely, a 19th-century Hungarian physician. He got the idea for this diagnostic tool after seeing similar streaks in the eyes of a man he was treating for a broken leg and the eyes of an owl whose leg von Péczely had broken many years before. At the First International Iridological Congress of Iridology, Ignaz von Péczely's nephew, Dr August von Péczely, dismissed this myth as an apocryphal, and maintained that such claims were irreproducible.
German contribution in the Naturheilkunde field is due to a minister Pastor Felke, who developed a form of homeopathy for treating specific illnesses and described new iris signs in the early 1900s. However, Pastor Felke was subject to long and bitter litigation. The Pastor Felke Institute in Heimshiem, Germany was established as a leading center of iridologic research and training.
Iridology became popular in the United States in the 1950s, when Bernard Jensen, an American chiropractor, began giving classes in his own method. This is in direct relationship with P. Johannes Thiel, Eduard Lahn (becoming an American under the name of Edward Lane) and J Haskell Kritzer. Jensen insisted on the body's exposure to toxins, and the use of natural foods as detoxifiers.
Few medical researchers managed to secure funding to study the possible non-visual functions of the eye. In a paper published in Medical Hypotheses, one such group tried to explain the observed patterns of iris transparency that distribute light into the ora serrata (the edge of the optic retina) by postulating a so-called functio ocularis systemica. Based on this hypothesis, the researchers have developed the experimental trans-iridal light therapy method; however, no independent confirmation of the theory and method exists to date.
Other results from the mentioned research include early attempts at computerized iris imaging for the purpose of iridologic diagnosis.
Iridologists generally use equipment such as a flashlight and magnifying glass, cameras or slit-lamp microscopes to examine a patient's irises for tissue changes, as well as features such as specific pigment patterns and “irregular stromal architecture”. The markings and patterns are usually compared to an iris chart that correlates specific zones of the iris with specific parts of the body. Typical charts divide the iris into approximately 80-90 zones. For example, the zone corresponding to the kidney is often in the lower part of the iris just before 6 o'clock. However, iridologists use a number of different maps that do not necessarily agree with one another.
According to iridologists, details in the iris are supposed to reflect changes in the tissues of the corresponding body organs. For example, acute inflammatory, chronic inflammatory and catharral signs are said to indicate involvement, maintenance, or healing of corresponding distant tissues, respectively. Other features that iridologists look for are contraction rings and Klumpenzellen, which are said to indicate various other health conditions, as interpreted in context.