Iridology-

is the diagnosis of disease by looking at the iris of the eye, and iridologists believe “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 concept has been disproven over and over again, yet iridology continues to exist as a belief system that by examining the iris, disease can be diagnosed.   Those practicing this art are called iridologists.  The history of iridology is somewhat bizarre and demonstrates how dangerous it is to make unrelated connections between events.  As a child in mid 1800s, Ignatz von Peczely, a Hungarian physician, noted streaks in the eye of a man with a broken leg and the eyes of an owl whose leg von Peczely had broken many years before, therefore associated streaks in the iris with broken legs, and made the assumption one could diagnose broken legs by observing the streaks in the iris. .  By 1893, Nils Liljequist from Sweden published an atlas of the iris known as “Diagnosis of the Eye”.

Evidence of effectiveness: 

A study to determine whether iridology could correctly pick patients with colorectal cancer found that iridologists correctly detected 52% of cancer patients and 53% of control patients, making iridology no different than chance in detecting cancer.  (Ophthalmologe 2008 Jun;105(6):570-4).   Another study found iridology identified the correct diagnosis of cancer (breast, overy, uterus, prostate, colorectum) in only 3 of 68 patients that had cancer, therefore iridology was of no value in diagnosis of cancer. (J Altern Complement Med 2005 Jun;11(3):515-9).  Similarly 3 iridologists in 1979 were unable to determine normal patients from those with kidney disease with one of the iridologists deciding that 88% of normal patients had kidney disease and another judged 74% of those with kidney disease as normal.  Another study on gall bladder disease showed iridology to be incapable of determining normal from abnormal gall bladders.  The uncontrolled experiments conducted by iridologists with bias built into the experiments do show positive results, but because they are uncontrolled, the responses do not rise to the level of scientific validity. 

Painbytes assessment: Two thumbs down.  This belief system is overtly dangerous to the health of individuals given the inability to accurately diagnose disease and the propensity to diagnose normal people as having disease.  Delays in treatment in those with disease and unnecessary treatments of those without make iridology no different than a scam.