Iridology (also known as iridodiagnosis) is an alternative medicine technique whose proponents believe that patterns, colours, and other characteristics of the iris can be examined to determine information about a patient’s systemic health.
Practitioners match their observations to iris charts which divide the iris into zones corresponding to specific parts of the human body.
Iridologists see the eyes as “windows” into the body’s state of health. Iridologists use the charts to distinguish between healthy systems and organs in the body and those which are overactive, inflamed, or distressed.
Iridologists believe this information may be used to demonstrate a patient’s susceptibility towards certain illnesses, to reflect past medical problems, or to predict later consequences of health problems which may be developing.
Iridology is not supported by quality research studies and is considered pseudoscience and quackery by most medical practitioners and eye care professionals.
The iris is the greenish-yellow area surrounding the transparent pupil (showing as black). The white outer area is the sclera, the central transparent part of which is the cornea.
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 compared to an iris chart that correlates zones of the iris with parts of the body. Typical charts divide the iris into approximately 80-90 zones.
For example, the zone corresponding to the kidney is in the lower part of the iris, just before 6 o’clock. There are minor variations between charts’ associations between body parts and areas of the iris.
According to iridologists, details in the iris reflect changes in the tissues of the corresponding body organs.
One well-known practitioner, Dr. Bernard Jensen, puts it this way: “Nerve fibers in the iris respond to changes in body tissues by manifesting a reflex physiology that corresponds to specific tissue changes and locations.”
This means that a bodily condition will translate to a noticeable change in the appearance of the iris.
For example, acute inflammatory, chronic inflammatory and catarrhal signs may indicate involvement, maintenance, or healing of corresponding distant tissues, respectively.
Other features that iridologists look for are contraction rings and Klumpenzellen, which may indicate various other health conditions, as interpreted in context.
The first explicit description of iridological principles such as homolaterality (without using the word iridology) 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 Ignaz von Peczely, a 19th-century Hungarian physician.
The most common story is that 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 Peczely had broken many years before.
At the First International Iridological Congress, Ignaz von Peczely’s nephew, August von Peczely, dismissed this myth as apocryphal, and maintained that such claims were irreproducible.
The German contribution in the field of natural healing 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 Felke Institute in Gerlingen, Germany was established as a leading center of iridological research and training.
Iridology became better known 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 (who became an American under the name of Edward Lane) and J Haskell Kritzer. Jensen insisted on the importance of the body’s exposure to toxins, and the use of natural foods as detoxifiers.
The majority of medical doctors reject all the claims of all branches of iridology and label them as pseudoscience or even quackery. Iridologists are rarely physicians. Iridology is only studied at private institutions, and it is not taught at medical schools.
Critics, including most practitioners of mainstream medicine, dismiss iridology as published studies have indicated a lack of success for its claims.
Clinical data does not support any correlation between illness in the body and coinciding observable changes in the iris.
In controlled experiments, practitioners of iridology have performed statistically no better than chance in determining the presence of a disease or condition solely through observation of the iris.
It has been pointed out that the premise of iridology is at odds with the fact that the iris does not undergo substantial changes in an individual’s life. Iris texture is a phenotypical feature which develops during gestation and remains unchanged after birth.
There is no evidence for changes in the iris pattern other than variations in pigmentation in the first year of life, eventual freckles and variations caused by glaucoma treatment. This stability of iris structures is at the foundation of iris recognition for identification purposes.
Scientific Research Into Iridology
Well controlled scientific evaluation of iridology has shown entirely negative results, with all rigorous double blinded tests failing to find any statistical significance to its claims.
In a study published in the Journal of the American Medical Association (Simon et al. 1979), three iridologists incorrectly identified kidney disease in photographs of irises and often disagreed with each other.
The researchers concluded: “iridology was neither selective nor specific, and the likelihood of correct detection was statistically no better than chance.”
Another study was published in the British Medical Journal (Knipschild 1988) by Paul Knipschild MD, of the University of Limburg in Maastricht, selected 39 patients who were due to have their gall bladder removed the following day, because of suspected gallstones.
He also selected a group of people who did not have diseased gall bladders to act as a control. A group of 5 iridologists examined a series of slides of both groups’ irises.
The iridologists were not able to identify correctly which patients had gallbladder problems and which had healthy gall bladders.
For example, one of the iridologists diagnosed 49% of the patients with gallstones as having them and 51% as not having them. Dr Knipschild concluded: “this study showed that iridology is not a useful diagnostic aid.”
Iridologists defended themselves and attacked the methodology of the study. Edzard Ernst said in 2000: “Does iridology work? This search strategy resulted in 77 publications on the subject of iridology.
All of the uncontrolled studies and several of the unmasked experiments suggested that iridology was a valid diagnostic tool.
The discussion that follows refers to the controlled, masked evaluations of the diagnostic validity of iridology. In conclusion, few controlled studies with masked evaluation of diagnostic validity have been published. None have found any benefit from iridology.”