Iridology – is the eye a window to all disease?
When starting out as a doctor I did not get offended when people automatically assumed that I was a nurse. However, now I am training to be an ophthalmologist, I get very offended when people confuse what I do with iridology.
Mainly I find it quite scary that there are some people who do not seem to even be aware of the difference. Ophthalmologists are medical doctors (6 years at university and one intern year) who then do at least another 5 years additional training to specialize in diseases of the eye and eye surgery. Iridologists on the other hand, can complete a certificate of iridology in 72 hours (3 hours, one night a week for 6 months). 1
So what is iridology? Iridology is the study of the iris to diagnose diseases in other organs and tissues of the body. This is based on the theory that each organ is represented by a specific area of the iris. Changes in the texture and colour of the iris in these positions are then thought to reflect disease in the organ represented there. For example 12 o'clock represents overall vitality and quality of life. Thus if there is a hole or a yellow tint in this area then energy levels are said to be down. Or if there is discoloration between 7.40-7.50 on the right eye then there are meant to be liver problems. I love this quote from www.iridologyworks.com:
"Eyes are genetically either blue or brown so any variations on that indicate malfunctions…. As the body gives up … yellow-white shows [in the] deeper layer of fibers. Brown indicates the problem has sunk into even deeper tissue and black is a sign of despair within the tissues."
Oh no, I don't want my tissues to be in despair!
Of course what any thoughtful patient should ask is how were the iridology charts elucidated? How do they know that 7.40-7.50 corresponds to the liver? The origins of iridology are interesting. Ignatz von Péczely, a 19th-century Hungarian physician is generally accredited with starting iridology. Apparently he saw a dark streak in the eyes of a man he was treating for a broken leg and it reminded him of a similar dark streak in the eyes of an owl whose leg he had broken years earlier. Von Péczely then went on to document similarities in eye markings and illnesses in his patients. He called this technique "augendiagnostik", which translated to iridology. (At the First International Iridological Congress, Ignaz von Péczely's nephew, August von Péczely, dismissed the story of the broken leg as pure myth.) In the early 1900s a German, Pastor Felke described new iris signs. Iridology became better known in the United States in the 1950s, when Bernard Jensen, an American chiropractor, began giving classes in his own method. There is still little evidence about how the iris maps were actually refined. If von Péczely or others continued by looking for iris changes in people who already had disease then he could have convinced himself of certain correlations. However in the 1800s diseases may not have been precisely or accurately diagnosed in many cases. There would certainly have been no proof of causal relationships. Neuroscientists have well proven that the human brain is designed to find patterns. Thus we can often convince ourselves that patterns exist where there are none, by giving extraordinary significance to confirmations, while ignoring or not seeking disconfirmations.
Less imaginatively, medical doctors see the iris as the colored part of the eye that regulates the amount of light entering the eye. However, there are certain symptoms of non-ocular disease can be detected by examining the eye. For example, nodules may be seen on the iris in patients with neurofibromatosis. Other diseases such as diabetes, high blood pressure and Wilson's disease can manifest as certain changes within other parts of the eye. This is recognizing symptoms of disease by looking in the eyes, very different from what iridology claims to be able to do.
What about scientific studies into the validity of iridology? In a study published in the Journal of the American Medical Association, three iridologists incorrectly identified nearly all of the study slides of the irises of 143 healthy and diseased people. Researchers concluded that "iridology was neither selective nor specific, and the likelihood of correct detection was statistically no better than chance."2 Similar results involving five Dutch iridologists were published in the British Medical Journal 3. In this study 39 patients who were due to have their gall bladder removed the following day (because of suspected gallstones) and another selected a group of people, who did not have diseased gall bladders, were examined by iridologists (using slide photographs). The iridologists were not able to identify correctly which patients had gall bladder problems and which had healthy gall bladders. In a more recent study of 110 patients of whom 68 subjects had histologically proven cancers, iridology identified the correct diagnosis in only 3 cases (sensitivity, 0.04).4
At best iridology is harmless and may give patients access to someone who has the time to listen to their problems at length (most places seem to book at least a 30 minute appointment, you would be lucky to get 10 minutes with a general practitioner.) At worst it could delay the diagnosis of serious medical conditions, misdiagnose or cause people to stop medically prescribed treatment.
If the premise of iridology is that the iris changes with disease, then why are companies using the stability of iris structures as the foundation of iris recognition for identification purposes? 5
- Simon A, Worthen DM, Mitas JA 2nd. An evaluation of iridology. JAMA. 1979 Sep 28;242(13):1385-9.
- Knipschild, P. Looking for gall bladder disease in the patient's iris. BMJ. 1988 Dec 17;297(6663):1578-81.
- Munstedt. K, El-Safsdi, S et al. Can iridology detect susceptibility to cancer? A prospective case-controlled study. J Altern Complement Med. 2005 Jun; 11(3): 515-9.