Iridology – Part 3

By: Dr. John Ankerberg and Dr. John Weldon; ©2006
Scientific studies have proven that iridology is worthless. In fact, iridology has failed every carefully controlled scientific test given it; at least, the authors could find no exceptions. They provide illustrations in this article.

The Results of Testing

In New Age Medicine, Reisser, Reisser, and Weldon briefly discussed the issue of iridology and science.

If the iris is indeed blessed with such enormous diagnostic potential, why is iridology not taken seriously in the scientific community?
In fact, iridology is taught neither in medical school nor in high school biology classes, nor is it practiced… by optometrists or ophthalmologists. As with many alternative therapies there are two fundamental reasons for this wholesale lack of acceptance: iridology’s basic premise is highly suspect, and its performance has not earned a passing grade using ordinary methods of scientific investigation.
One major theory problem is the assumption that the iris’ connections with the central nervous system allow detailed messages to be sent to it from the rest of the body…. Unfortunately, the elaborate neurologic pathways necessary for such a powerful capability have yet to be demonstrated, or even deemed plausible, in spite of years of neuroanatomical studies of the eye and central nervous system.[1]

But Dr. Jensen boldly challenges, “I am willing to put iridology to the most severe tests. During the eighteen years in which I have been studying and applying this science, I have not been trying to fool myself.”[2] The reader may judge for himself.

Scientific studies have proven that iridology is worthless. In fact, iridology has failed every carefully controlled scientific test given it; at least, we could find no exceptions. Consider the following illustrations. (In the tests cited below, photo­graphs of patient’s iris were used, for obvious reasons. Iridologists routinely claim they can effectively diagnose by photograph, thus all parties agreed on the proce­dure at the start of these tests.)

As reported in the Journal of the American Medical Association, scientific researchers at University of California San Diego tested three iridologists (including Dr. Jensen himself), and three ophthalmologists by having them study the iris photo­graphs of 143 subjects, 48 of whom had overt kidney failure.[3] The researchers gave iridology its best shot. Two of the three iridologists had been “using the technique as their primary method of analysis of patients for more than forty years.” But the iridologists failed miserably. The number of false positives (healthy people diagnosed as having disease) and false negatives (diseased people diagnosed as healthy) was frightening. In fact, the iridologists’ accuracy was found to be worse than what one would expect with chance guessing. In other words, the iridologists would have been more accurate by picking their answers out of a hat than by deriv­ing them from an examination of the iris. Thus,

…the 2.5 percent level of renal disease diagnostic accuracy with iridology— only 11 of 20 patients with disease are correctly identified, while 421 normal people are identified as having disease—does not warrant reliance on this technique in the detection of renal disease…. There is a serious potential psychological harm to the subject of carrying the burden of detected “disease.” Of greater interest to physicians is the false-negative analysis. One of the observers (an iridologist), who employs the technique and draws conclusions based on it, correctly identified only 26 percent of the patients undergoing dialysis as having kidney disease. Physicians are well aware of the harm that can be done to these patients if they were to rely on iridology and thereby go without proper treatment.[4]

Dr. Jensen afterwards criticized the study, allegedly for other reasons than the fact he miserably failed it. He argued that the study’s use of serum creatinine level to indicate kidney disease was not valid.[5] Serum creatinine, however, is accepted and used around the world as a significant indicator of kidney function.

Iridologists have also claimed that the 421 people in perfect health identified as having kidney disease would certainly have kidney disease in the future because, as noted earlier, iridology can allegedly discern “subclinical” disease, that is, dis­ease that will appear in the future. But, of course, at this point the iridologists prove nothing. If the patient never develops the problem, they claim that their treatment prevented it. If the patient does develop it, then they were right all along.[6]

Consider another study. In this case a physician examined 762 patients with very severe disease. Among them were 60 Army veterans, many of whom had ampu­tated limbs. Iridology was again proven false and harmful:

Among the 762 patients only 18 (that is 2.7 percent) had a sign in the area that the iridology chart assigned to the affected organ. More than 50 percent, however, had pathological signs in areas of organs that had never been involved. The same investigator made a test with one of the most prominent iris-interpreters of his time which was witnessed by several doctors and laymen. Iridologist Klaeser was asked to diagnose patients with severe ailments and mutilations that were obvious even to medical laymen.[7]

But after eight successive attempts, the experiment was discontinued because the iridologist had given nothing but wrong diagnoses. One patient with an ampu­tated leg, for example, was discovered to have only “marked congestion of the spinal cord.”[8]

A different scientific study was done at the University of Melbourne in Australia and reported in the Australian Journal of Optometry for July 1982. This controlled clinical study compared iridology evaluations with patients’ known medical histories. One phase of the study had iridologists diagnose “before” and “after” iris photographs of subjects who had developed a serious disease. Iridologists were then asked to determine whether or not a change in the iris had occurred and to tell which organ had been affected.

Significantly, the only set of photographs “determined to have changes was a set taken as a control on the same subject two minutes apart!” The conclusion of the study was that “there were no detectable iris changes of the type depicted in the commonly used iris diagnosis charts.”[9]

Another study was conducted at the University of Lindbergh in the Netherlands and reported in the British Medical Journal for December 17, 1988. It also revealed that iridology does not work.

All of this is why Dr. Russell Worrall concluded in the October 1984 Journal of the American Optometric Association,

After 104 years, the facts of iridology have yet to be established…. To my knowledge there are no well conceived, documented and published studies which support the validity of the clinical information presented on the iris charts or which demonstrate the underlying anatomical and physiological processes. (Scientific Studies in English and Extensive Critical German Citations) demonstrate that there is no statistical correlation between a diagnosis based on iris signs and actual medical conditions.[10]

Unfortunately, scientific studies discrediting iridology are rarely reported in the popular press; experiments which seem to validate it appear more desirable. This is why claims in the popular press must be evaluated critically. For example, Jensen cites the work of two researchers in Russia reported in The National Enquirer for May 23, 1978, that reported a 95 percent accuracy in 1,273 subjects with diag­nosed disease. Jensen also reported another study with an alleged 92 percent efficiency through iridology in the detection of kidney disease. However,

Jensen does not describe the details of these investigations, the nature of the controls or the standards used for diagnosis. These are important, because one iridologist in the San Diego study could also boast of having correctly identified 88 percent of those with kidney disease. Unfortunately, he reported that 88 percent of the normal subjects included in the study as a control were also suffering from kidney disease…. Therefore, without specific details of the design, the use of these studies is of no value when offered in support of iridology.[11]

Supposedly Correct Diagnosis

How do we explain the many claims of correct or “astonishing” diagnoses that occur in iridology? Such correct diagnoses can be impressive; for example, Dr. James Carter’s interest in iridology was sparked by a Canadian artist “whose astoundingly accurate iris reading” dissolved his skepticism.[12]

Such “accuracy” can occur in a number of ways that have nothing to do with the validity of iridology. Below we briefly show why iridology can seem to be effective when it really isn’t. We will also indicate that when genuinely accurate diagnoses are made, it may occur through spiritistic power, but not the power of iridology.

Why can iridology appear to be an effective method of diagnosis? First, consider that most patients will tell an iridologist their medical history, including the symptoms they are having, well before he examines their iris. This may supply the iridologist with sufficient clues to make an accurate diagnosis at least some of the time.

Second, iridology diagnosis characteristically involves speaking in vague and general terminology. The patient is left to fill in the details, but the initial diagnosis sounded right and the treatments seem to be helping, so the patient concludes that the diagnosis must have been correct.

For example, what does it mean that a liver or pancreas is “weak”?

The bulk of the diseases reported are vaguely stated conditions in organs, such as an “underactive” pancreas or “chronic weakness” in the lungs. Such vagueness permits clinicians to capitalize on any improvement in the way a patient “feels” as proof that the treatments are doing some good. Under those conditions, the cure rate and patient satisfaction in a clinical practice can be very high.[13]

Third, iridologists, like many other new age healers, are adept at self-justification. Because practitioners assume iridology is never wrong, some novel explanation is always available to explain errors, no matter how implausible. For the true believer, no conditions exist which could ever disprove iridology.

Consider a typical “safe” diagnosis, which although proven false, was neverthe­less rationalized. An investigative reporter was told by the iridologist that the whitish color coming from the iris of her eyes indicated acidity and mucus throughout the body and could result from eating too much meat, bread, and milk products. When the iridologists was informed the reporter was a vegetarian, she was told the acidity “could be a reverse effect from eating too much fruit and vegetables”![14]

Fourth, iridologists do not usually provide one single diagnosis but offer the patient an entire list of actual or potential problems. The more problems listed, the greater chance of being right at least once.

Some clients are amazed when their iris might “indicate” that a family relative has a particular problem or illness. But if the illness is common enough and if the word “relative” is defined generally enough (parents, children, spouse, aunts, uncles, third removed cousins, etc.), the iridologist may be proven true. Then there is always the entirely “safe” prediction of “future” disease which has absolutely no symptoms or indications in the present—except, of course, in the iris.

All the above factors—and more—can provide iridologists with a clientele of converts who are ready to broadcast the “amazing discoveries” of iridology far and wide.

But there is a further explanation for the possible success of iridology, which we will discuss next time.


  1. Paul C. Reisser, Teri K. Reisser, John Weldon, New Age Medicine: A Christian Perspective on Holistic Health (Downers Grove, IL: InterVarsity, 1988), pp. 142-143.
  2. Bernard Jensen, The Science and Practice of Iridology: A System of Analyzing and Caring for the Body Through the Use of Drugless and Nature-Cure Methods (Provo, UT: BiWorld Publishers, Inc., 1952), p. 10.
  3. Allie Simon, David M. Worthen, John A. Mitas, “An Evaluation of Iridology,” Journal of the Ameri­can Medical Association, September 28, 1979, p. 174.
  4. Ibid., pp. 1388-89.
  5. Russell S. Worrall, “Iridology: Diagnosis or Delusion,” in Douglas Stalker, Clark Glymour, eds., Examining Holistic Medicine (Buffalo, NY: Prometheus Books, 1985), p. 176.
  6. Reisser, Reisser and Weldon, p. 145.
  7. Samuel Pfeifer, M.D., Healing at Any Price? (Milton Keys, England: Word Limited, 1988), pp. 89- 90.
  8. Ibid., p. 90.
  9. Worrall, “Iridology,” p. 175.
  10. Russell S. Worrall, “Pseudoscience: A Critical Look at Iridology,” Journal of the American Optom­etric Association, October, 1984, p. 737, emphasis added.
  11. In Worrall, “Iridology,” p. 176.
  12. Berkeley Holistic Health Center, The Holistic Health Handbook: A Tool for Attaining Wholeness of Body, Mind, and Spirit (Berkeley, CA: And/Or Press, 1978), p. 157.
  13. Worrall, “Iridology,” pp. 177-178.
  14. Norma Meyer, The Daily Breeze, Torrance, CA, Sept. 5, 1982, p. 178.3NAStaff0306 Iridology – Part 3

Read Part 4

1 Comment

  1. […] Read Part 3 […]

Leave a Comment