Iridology is a technique in 'alternative' medicine that is theoretically able to determine information about a patient's health by close examination of their iris. By comparing patterns, colors and any other markings and characteristics of a patients iris to 'iris charts', which segment the iris into a variety of zones that supposedly correspond to specific parts of the human bodies, practitioners of Iridology are supposedly able to tell "weaknesses and strengths" of the corresponding areas.
In their own words;
"Iridology is the study of the iris, or coloured part of the eye. The iris reveals changing conditions of every part of the organ of the body. Through various marks, signs and discolouration in the iris, nature reveals inherited weaknesses and strengths. Iridology cannot detect a specific disease however it can tell an individual if they have over or under activity in specific areas of the body"
"Iridology is generally safe, non-invasive and painless. It is not a treatment therapy but rather a diagnostic tool used to detect underlying signs of developing disease. The goal of Iridology is therefore to recognise health problems at their earliest stages and to suggest ways to keep disease from developing.." - Natural Therapy Pages
Here I think it is important to note that here they say it focuses on general health problems, such as back problems for example, and not necessarily arthritis or any specific problems. Some Iridology practitioners claim however that they can diagnose a patient's complete history of past illness and previous treatment. Many claim that they can predict a patients possible upcoming health problem.
Iridology counts on there being connections from each organ to the iris.
"The iris is the most complex enternal structure of the human anatomy. It has a reflex connection to every organ and tissue of the body by way of the nervous system. Through the optic nerves, which are attached to the eyes, visual information is sent to the brain. At the same time there is information sent back to the eyes from the brain about the state of the organs and tissues in your body." - The intergrated Iridology Textbook - Toni Miller
To start with these claims it is important to realise a few things about the eye that go against Iridology. The iris colour is determined largely by three main genes. The colour we see is a combined effect of texture, pigmentation, fibrous tissue and blood vessels within the iris stroma (in brown eyes the vessels in the stroma have pigmentation and in blue or albino eyes they don't). The iris is found to generally not undergo substantial changes over an individuals life and instead shows little change after one year after gestation. Freckles and other variations can occur because of glaucoma treatment but this is a known symptom and is not area specific as diseases are believed to be in Iridology.
The following quotes are from a former Iridoligist, I strongly recommend reading the article;
“I soon found that structure "changes" could be created on the video record by changing the angle of the light to the eye. Areas that I thought were dark would suddenly show healing lines when the position of the light changed. Thick white lines would change to thin gray lines when the light moved. More than once during this period an eminent Iridologist would call me to his office and show me a change he had recorded in patient's iris minutes after doing a spinal adjustment. After closely examining his recordings, it became obvious to me that his light position and the angle of the camera to the eye had varied from time to time causing the appearance of a change in the iris.”
“The changes I found in a few irises were actually in the color. When I experimented with changes in angles, I found that the angle of light going into the eye, and the level of lighting in the room, had an effect on pupil size. Pupil size had a direct link to fiber size, and fiber size seemed, in some cases, to be related to colors that appeared in the iris. This was more obvious in someone who had more than one color present in his or her iris. I, for example, have brown, green, yellow, and blue appearing in my iris. In different degrees of lighting my eyes have a different appearance. It is for this reason that different people have told me that my eyes are entirely brown, green, or blue."
"In a smaller way pupil size affects the appearance of color in a magnified iris. Not only does light have influence on pupil size, but the autonomic nervous system also has an influence on the pupil size, thus a person's degree of fear or alarm can change pupil size. An Iridologist purports to be capable of telling a great deal about a person based on the color of single fiber. This variable became quite important for that reason. When I corrected for all these variables, I found very few iris changes. More importantly, I found very few iris changes in people who had significant health changes in the prior months. In many of the cases where the iris seemed to have changed, it had changed inappropriate to the physical changes that had been known to occur. In other words, I discovered that the iris did not reflect the level of health in the body.” - Confessions of a former Iridoligist - Joshua David Mather Sr.
So science is against Iridology, but what do the studies show. In 1979 Bernard Jensen, a renown alternative medicine practitioner who wrote many books, taught Iridology and saw (he claims) 350,000 patients in his life, and two other Iridologists took part in a scientific test. In the test published in the Journal of the American Medical Association they examined the eyes of 143 persons in an attempt to determine which ones had kidney impairments. 48 were diagnosed with impairments and the rest had normal function. So what were the results? Well;
- All three failed to have a statistically significant ability to detected kidney disease
- One judged 88% to of normal patients to have kidney disease while;
- One judged that 74% of patients needing treatment were normal
But one study isn't always convincing on it's own. A study posted in the British Medical Journal tested Iridologists ability to detect gall bladder problems. Paul Knipschild MD, University of Limburg, chose 39 patients due to have their gall bladder removed the next day as well as 39 control subjects of the same sex and age. The following is an excerpt from the report;
“The presence of an inflamed gall bladder containing gall stones is said to be easily recognised by certain signs in the lower lateral part of the iris of the right eye. Stereo colour slides were made of the right eye. Stereo colour slides were made of the right eye of 39 patients with this disease and 39 control subjects of the same sex and age. The slides were presented in a random order to five leading Iridologists without supplementary information. The prevalence of the disease was estimated at 56%. The median validity was 51% with 54% sensitivity and 52% specificity. These results were close to chance validity (iota = 0.03). None of the Iridologists reached a high validity. The median interperformer consistency was 60%. This was only slightly higher than chance consistency (kappa = 0.18). This study showed that Iridology is not a useful diagnostic aid.”
So the Iridologists were not able to correctly identify which patients were which any more than statistically probable (4% difference). I further read a short paper in defence of Iridology.This paper claimed links between short sightedness and a variety of things. Some of it reminded me of astrology, I found nothing worth mentioning here but I thought I should link to it to let people make up their own minds.
“The logical thinker is a nearsighted person who talks a lot, asks questions and gives the impression of being rigid in their ideas and willingness to step out of their inflexible belief system.” and etc.
I advise reading at least some of it as this is something that is being cited as a successful “study” on some iridology sites. The author Roberto M. Kaplan is not to be confused with the mainstream doctor Robert Kaplan.
In my point of view I can't find any convincing evidence for iridology. It has no basis in science and has been shown to not work in double blinded clinical studies. The belief seems to be encouraged by the age-old saying that the eyes are a window to the soul and there is little other evidence out there to give it further credence.