Often called “the window to the soul,” the eyes express joy, sadness and fear. The iris is the most obvious element of the external eye, its color being a major factor in ethnic and family identity. In fact, eye color has been the subject of numerous studies by researchers, including geneticist Gregor Mendel.
In recent years, naturopaths have renewed their interest in a method of disease recognition based on detailed characteristics of the human iris. Iridology represents the study of carefully mapped sections of the iris and the assigned organ systems represented by these areas.1
Background
Iridology, also known as iridodiagnostics, is an alternative medicine technique that uses the colors, patterns, and various other properties of the iris to assess an individual’s overall health.2 The technique of iridology is based on the belief that every organ in the human body has a corresponding region in the iris. So, the principle is that organ function can be examined by simple inspection of the iris.
Iridologists typically use cameras, flashlights, and microscopes to examine the patient’s iris for tissue changes, stromal irregularities, and pigment patterns. The results are then compared to an iris diagram, which allows different parts of the human body to be correlated with different areas of the iris.
A typical iris diagram usually divides the iris into approximately 90 zones, each corresponding to a different part of the human body. Iridologists believe that the details reflected by the iris are usually changes in the tissues of the corresponding body organelle.2
According to proponents of this therapy, iridology is not intended to diagnose disease, but rather to detect impaired organ functions attributable to environmental toxins, poor diet and fatigue.
For iridologists, variations in iris color (sparkles and rings) have specific meaning and can even indicate whether a suspected condition is acute/inflammatory, chronic/inflammatory, or allergic.2
Some iridologists further divide organ system dysfunction according to the color of the iris. They believe that lymphatic diseases are associated with a blue or blue-gray iris and that these individuals are prone to atopic conditions; hematogenous pathology is linked to brown-eyed individuals who are more prone to anemia and endocrine disorders; Gallstone disease is associated with blue and brown irises and is indicative of gastric deficiencies.3
Iridology was used as early as the 17th century in Europe, but the practice was not noticed in the United States until the second half of the 20th century.1 Despite its long history, there is little scientific data to support the usefulness of iridology.
Science
Of the four conditions most commonly evaluated by iridology practitioners (hypertension, cancer, gallbladder disease, and kidney disease), only hypertension received a strength of evidence grade of “C,” while all three other conditions scored very low. “D” level displays.3
In one study, researchers explored the overlap of tumor necrosis factor alpha (TNF-alpha), hypertension, and specific variations in iris constitution.4 Eighty-seven Korean patients with known hypertension were compared with 79 Korean participants without known blood pressure problems.
Individuals were assessed for iris characteristics, blood pressure, and the presence or absence of the TNF-alpha genotype.4 The study results did not show a statistically significant difference in genotype and presence of hypertension, but there was a clear elevation in hypertensive patients with the iris feature denoting cardio connective tissue weakness -renal.4
In another study involving the same patient population, researchers examined study participants to determine a correlation between iris characteristics and the presence or absence of apolipoprotein-E (apoE).5There is a well-established relationship between this genotype and vascular diseases, including hypertension.5In a blinded study, patients were examined by iris pattern and then tested for apoE genotype.5There was a significant correlation between iris type and hypertension, as well as an increased percentage of apoE presence in these same hypertensive patients.5
These two studies were not large enough to support the practice of iridology. Further trials with larger study populations are needed.
Studies of this practice have also generally focused on the potential usefulness of iridology as a cancer screening tool. One trial examined age- and sex-matched participants to determine the possibility of colorectal cancer.6Twenty-nine patients with a known diagnosis of this disease were matched to 29 healthy patients.
The researchers presented photographic slides of each participant’s eyes to two trained iridology practitioners. At the end of the study, the presence of cancer was detected in only 50-53% of patients, which was no better than chance.6
In another trial exploring iridology and cancer detection, 68 patients with known cancer and 42 healthy patients were examined by a single experienced iridologist. Without any other information than the visualization of the iris, the practitioner correctly detected only three cases of cancer.7
Security, interactions
Due to the non-interventional nature of this practice, there are no contraindications to its use. In the United States, there are many training and education organizations for iridology, but the practice is not regulated by the health care industry.
Summary
Iridology has intriguing possibilities, but, to date, evidence-based studies do not support its safety and usefulness. Some researchers plan to improve the accuracy of the practice using computer-assisted diagnostics. But for the moment, the study of the iris in the indications of systemic diseases is far from being a viable clinical tool.
Sherril Sego, FNP-C, DNP, is a clinician at the VA Hospital in Kansas City, Missouri, where she practices adult medicine and women’s health. She also teaches at the University of Missouri and University of Kansas schools of nursing.
The references
- LF Rooms, Silva MJ. Iridology: a systematic review. Rev Esc Enferm USP. 2008;42:596-600.
- Buchanan T. An investigation into the relationship between anatomical features of the iris and systematic disease with reference to iridology. Comp Ther Med. 2006;4:98-102.
- Iridology page. Natural Standard website. Available atwww.naturalstandard.com/index.asp.
- Yoo CS, Hwang WJ, Hong SH et al. Relationship between iris analysis and TNF-alpha gene polymorphism in hypertensives. Am J Chin Med. 2007;35:621-629.
- Um JY, Hwang CY, Hwang WJ et al. Association between iris constitution and apolopoprotein E gene polymorphism in hypertensive patients. J Alternate Complement Med. 2004;10:1101-1105.
- Herber S, Rehbein M, Tepas T et al. Looking for colorectal cancer in the patient’s iris? Ophthalmologist. 2008; 105:570-574.
- Münstedt K, El Safadi S, Brück F et al. Can iridology detect cancer susceptibility? A prospective case-control study.J Alternate Complement Med. 2005;11:515-519.
All electronic documents were accessed on December 15, 2012.
From the January 1, 2013 issue of Clinical Advisor
