Iridology (also known as iridodiagnosis[1] or iridiagnosis[2]) is an alternative medicine technique whose proponents claim that patterns, colors, and other characteristics of the iris can be examined to determine information about a patient's systemic health.

Iridologists claim they can use the charts to distinguish between healthy systems and organs in the body and those that are overactive, inflamed, or distressed.

[6][7] 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 first use of the word Augendiagnostik ("eye diagnosis", loosely translated as iridology) began with Ignaz von Peczely, a 19th-century Hungarian physician who is recognised as its founding father.

[11] The German contribution in the field of natural healing is due to a minister Pastor Emanuel Felke, who developed a form of homeopathy for treating specific illnesses and described new iris signs in the early 1900s.

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.

In 1979, in collaboration with two other iridologists, Jensen failed to establish the basis of their practice when they examined photographs of the eyes of 143 patients in an attempt to determine which ones had kidney impairments.

To date, clinical data does not support 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.

[14] Iridology is based on a premise that is at odds with the fact that the iris does not undergo substantial changes in an individual's life.

[6][7] Well-controlled scientific evaluation of iridology has shown entirely negative results, with all rigorous double blind tests failing to find any statistical significance to its claims.

[16] In 1979, Bernard Jensen, a leading American iridologist, and two other iridology proponents failed to establish the basis of their practice when they examined photographs of the eyes of 143 patients in an attempt to determine which ones had kidney impairments.

[9] Another study was published in the British Medical Journal which selected 39 patients who were due to have their gall bladder removed the following day, because of suspected gallstones.