There are many medical pseudosciences that persist despite a utter lack of either plausibility or evidence for efficacy. Some practices emerged out of their culture of origin, or out of the prevailing ideas of a pre-scientific age, while others were manufactured out of the imagination of perhaps well-meaning but highly misguided individual practitioners. They were just made up – homeopathy, for example, or subluxation theory.
Iridology belongs to this latter category – a system of diagnosis that was invented entirely by Ignatz Peczely, a Hungarian physician who first published his ideas in 1893. The story goes that Peczely as a boy found an owl with a broken leg. At the time he noticed a prominent black stripe in the iris of one eye of the owl. He nursed the bird back to health and then noticed that the black line was gone, replaced by ragged white lines. From this single observation Peczely developed the notion of iridology.
Peczely’s idea was that the iris maps to the rest of the body in some way, and therefore the flecks of color in the iris reflect the state of health of the various body parts. This basic approach to diagnosis or treatment is called the homunculus approach – the idea that one part of the body maps to the rest of the body, including the organ systems. Reflexology, auricular acupuncture, and even straight chiropractic follow this approach.
This is what might have happened next: After publishing his initial observations, Peczely set out to test his ideas with well-designed observations that were capable of proving his hypothesis wrong. He carefully built a body of descriptive, but well-established, facts about the relationship between the iris and health. Later, anatomists discovered the underlying mechanism of this connection – a vast system of interconnectedness between the iris and the rest of the body. Further research built on the iris connection, and later medical scientists found more and more ways to exploit this fascinating aspect of anatomy and physiology.
Of course, this is not what happened. Peczely did not do any serious scientific research. Rather, he simply invented a pseudoscience, by drawing maps of the iris that were as much a product of his imagination as observation, and were largely the result of confirmation bias. He did not perform blinded studies, or produce the kind of evidence that could separate a real phenomenon from an imaginary one. Iridology, as his practice became known, is the N-rays of medical diagnosis. Further, no subsequent science has supported the plausibility or reality of iridology. There is no underlying anatomy or physiology that can explain how the iris would reflect the state of function of any other part of the body.
This, unfortunately, has not stopped iridology from surviving on the medical fringe for more than a century. The modern popularity of iridology, especially in the US, can be traced back to a chiropractor named Bernard Jensen. He published the book, The Science and Practice of Iridology in 1952. Iridology, or iris diagnosis, continues to be practiced by so-called alternative practitioners, including some chiropractors and naturopaths. It has never been recognized as a legitimate medical practice. For example, for $150 naturopath Frank Navratil will diagnose you from a digital image of your eyes.
Often the iris diagnosis (which can also be done by software analysis) leads to recommendations for supplementation, which are conveniently sold by the iridologist. Here is a description of how iridology is used by a proponent:
The iris reveals changing conditions of every part and organ of the body. Every organ and part of the body is represented in the iris in a well defined area. In addition, through various marks, signs, and discoloration in the iris, nature reveals inherited weaknesses and strengths.
By means of this art / science, an iridologist (one who studies the coloration and fiber structure of the eye) can tell an individual his/her inherited and acquired tendencies towards health and disease, his current condition in general, and the state of every organ in particular.
Iridology cannot detect a specific disease, but, can tell an individual if they have over or under activity in specific areas of the body. For example, an under-active pancreas might indicate a diabetic condition.
Other sites caution that iridology cannot diagnosis pregnancy, because that is a natural condition of the body, and also cannot diagnose prior surgery, as anything that happens under anesthesia will block the signals that would otherwise change the iris. In other words – iridology only tells you about the susceptibility for disease – it cannot actually diagnose a disease or any other verifiable condition. This reasoning is called special pleading – the invention of a special rationalization for each fact that might otherwise falsify a claim or belief. Iridology, apparently, can only discern those things that cannot be verified or falsified.
What you end up with is a medical cold reading – similar to what a mentalist does to create the illusion of mind reading or psychic powers. While “reading” the iris the iridologist can ask about certain health issues. If they are present, that is used to validate iridology. If absent, then the subject simply has a susceptibility for the missing problem.
Iridology lacks any plausibility and its history is that of a pseudoscience, not a legitimate practice. But still we listen to the best scientific evidence in determining whether or not iridology is real. Perhaps Peczely got lucky and made a correct observation despite his lack of scientific confirmation. If iridologists could demonstrate that their readings provide real information, then we would have to take their claims seriously.
Iridology Chart of the Right Eye Iris
Remember that prank where you would tell someone that you could tell if someone had cancer if their hand was bigger than their face? And then you’d smack their hand into their face when they tried to compare the two? Now imagine that someone told you that looking at your eye color could tell them if you had a broken foot. Sounds crazy, right?
Iridology is the process employed by some alternative-medicine practitioners where they attempt to divine medical problems by staring at your eyes. They have developed this into a full pseudo-science complete with training schools and certification programs. Where chiropractors and osteopaths claim that all diseases can be traced back to skeletal “imbalances,” iridologists believe that all diseases and ailments can be detected by observing the iris. Iridologists believe that the the oculomotor nerve somehow changes the iris to indicate disease and infirmity. They believe that the health of every organ can be determined by examining the color, shape, tint, and depth of fibers that make up the iris.
They say that the eyes are the gateways to the soul. Well, these guys take that a bit too literally.
Iridologists generally believe that a dark area of the eye indicates a loss of nerve activity for that region. Oh, I should mention that the eye is divided radially into sections that indicate each major body area. How they came up with each slice, I have no idea. If dark areas mean loss of nerve activity, that means that light areas mean more activity such as pain.
Here’s the biggest problem with all of that:
The iris doesn’t change a whole lot from birth until death. There’s enough of a variation over a decade to make biometric scanners a little iffy but there’s definitely no change detectable on the timescale that iridologists would need in order to give any credibility to their “profession.”
Here’s another major problem:
There is no evolutionary reason for the oculomotor nerve to be connected to every organ in the way that iridologists believe. It just doesn’t make sense. Any college anatomy class would show that this isn’t the case.
How do iridologists even exist?
Part of the reason is that as there is no government licensing authority, there’s no burden of proof that their practices are effective. There’s no blood tests to confirm diagnoses. Iridologists don’t boast of successful clinical trials because there are none. Unfortunately, anyone can claim anything so long as there is a disclaimer that they’re not legally allowed to diagnose or treat an illness.
And so, we continue the fight against the woo…
The final nail in the coffin: Procedure problems that would invalidate every test iridologists perform regardless of the lack of science behind the test.
In order for a test to be valid, it must be performed the same way using accurately calibrated equipment every time.
Iridologists typically conduct examinations using a penlight and their own judgement. No real tests. No records. Just looking at you. Only some use video recording equipment. In the examination room, the iridologist passes a penlight across the field of vision of the patient. As the penlight is passed at a different angle and at varying distance during each visit, a slightly different image of the iris will be recorded each time. This promotes confirmation bias to take over in suggesting that there was some change in the iris compared to the last visit.
On top of that, using a different penlight or the same penlight at a different battery charge level will change the hue of light being cast which, obviously, changes the exact iris color. That means different test results every time. The iridologists that use actual recording equipment will likely not place it at the exact same distance each time which also means a different iris illumination will be recorded. If all of that doesn’t confound the “test” enough, room lighting can drastically change the close-up appearance of an iris from room to room.
One former iridologist described his disillusionment with his profession coming from after he developed a mounted camera and lighting system. He discovered the truth that a basic anatomy class would have told him long ago: irises don’t change. After correcting for all of the previously mentioned variables, individual iris pictures taken over time appeared to be identical regardless of the current health of the individual. After a long moral quandary, he shut down his practice and began working towards an actual medical degree. Many (if not most) alternative-medicine practitioners really do want to help people. Unfortunately, they went down the wrong path at some point.
Herbalist Michael Tierra has described how he became disillusioned with iridology. After making various observations, he stopped using it but still hoped that it would turn out to have some value. Then, however:
A younger colleague fully equipped with the most up-to-date specialized iridology equipment introduced himself and stated that he wanted to give iridology readings at my clinic and at the same time monitor the course of my patients over a period of six months.
Given the fact that for most of us as well my patients six months is quite a long period, there was ample opportunity for many of these to go through a variety of health-related changes. Some people became well and got sick again with either the same or perhaps a different set of symptoms, others suffered injuries or operations. They all had their irises repeatedly photographed and studied by my colleague and myself. Where was Peczely’s owl or the markings he claimed to observe in patients of the 19th century Hungarian hospital ward? Where were the fine white healing lines that were supposed to knit together the small dark lacunae corresponding to the healing of operations and injuries of different parts of the body?
Our conclusion after six months: my colleague, trying to hold on to the fast disappearing shred of belief in the validity of iridology sheepishly and somewhat guiltily sold his camera to another would-be iridology enthusiast. I buried my official iridology magnifying head band in a box in a dark, hopefully soon forgotten area of my office closet, where I must confess it still remains after over 15 years, unopened [11].
Another former iridologist, Joshua David Mather Sr., has written a detailed account of the origin and termination of his beliefs. He began studying iridology at age nine when his father became a practitioner. He abandoned it at age 25 after examining polaroid films of many patients and finding out that although their symptoms often improved, their eye markings never changed
“But my alternative-medicine practitioner diagnosed me correctly!”
This is where cold-reading comes in. Cold-reading is the process that psychics and con-men use to divine information about an individual based on verbal and non-verbal cues. If a 20 year pack-a-day smoker comes in complaining of shortness of breath, constant coughing, bloody spittle, and general weakness there is a fair chance that they have lung cancer. It doesn’t take a doctor to guess what symptoms mean but it does take a doctor to correctly diagnose a problem and prescribe a remedy.
Therein lies the true danger of these alternative-medicine practitioners: Not getting the right medicine for a real problem. They can drain your wallet all day long without it mattering that much. However, when you cross over from eating herbs for “wellness” and into “trying to cure cancer with grass clippings” there is real harm being done. Because of taking a charlatan’s word for the correct course of treatment, real people die every day.
Ok, is there any truth to Iridology at all?
Nope. Numerous studies have shown that iridologists perform no better than random chance at determining healthy patients from sick patients.
Iridology Chart of the Right Eye Iris
MAIKONG IRIDOLOGY SOFTWARE Installation and operation
