Related Terms

  • Angle of Fuch’s, applied iridology, central heterochromia, cholesterol ring, ciliary zone, collarette, connective tissue type, Deck’s pancreatic signs, density, flower, healing lines, inner-directed personality, iris biometrics, iris diagnosis, jewel, lacuna, left-brain development, lesion, lipemic diathesis, lipid ring, lymphatic rosary, nutritive zone, outer-directed personality, papillary margin, parasite lines, pigment ruff, pinguecula, prolapsus of transverse colon, psora, pterygium, pupil size, pupil sphincter muscle, radial furrows, radial solaris, radials, rarefaction, Rayid model, right-brain development, ring of determination, ring of harmony, ring of purpose, rings of freedom, sclerology, scurf ring, shading, shakers, sodium ring, stomach ring, stream, stress rings, tobacco snuffing, topo labile, topo stabile, trabeculae, transversal, vascular transversal, weak iris.


  • Iridology is the study of the iris (colored part of the eye) with the intention of gaining information about underlying diseases. Naturopaths and other practitioners may use this technique.
  • Iridology is based on the belief that each body region and organ is represented at one specific location in the iris. Abnormalities in a region are suggested to correspond to abnormalities in the respective organ. This technique was developed in Budapest, Hungary in the 1800s by the physician Ignatz von Pezcely. Iridology was later adapted by Bernard Jensen, an American chiropractor. Jensen based his practice on detailed diagrams of the left and right irises, assigning every organ, many body parts, and several bodily functions to a specific location on one or both irises.
  • The popularity of iridology grew in the 1900s. Iridologists visually access the iris of their patients by direct examination or by studying close-up photographs. Some iridologists use sclerology, a technique that studies lines on the sclera (the white part of the eye), which they believe can show changes in health patterns and conditions. The Rayid model may also be used, which studies eye patterns with the aim to evaluate mental, emotional, spiritual, and physical balance.

Evidence Table


    These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

    Hypertension (diagnosis)

    Preliminary studies suggest that iridology may assist in the identification of individual predispositions for vascular diseases such as hypertension (high blood pressure). Further research is needed to confirm these findings.

    Cancer (diagnosis)

    There is currently limited available data supporting iridology as a diagnostic tool in cancer. Additional study is needed.

    Gallbladder disease (diagnosis)

    Preliminary study examined the ability of iridologists to diagnose gallbladder disease from slide photographs of patients with the disease and found no evidence of agreement or diagnostic accuracy. There is no evidence supporting iridology as a diagnostic tool in gallbladder disease.

    Kidney disease (diagnosis)

    Preliminary study submitted photographs of irises of kidney disease patients to practicing iridologists and found no evidence of accurate detection of kidney disease. There is no evidence supporting iridology as a diagnostic tool in kidney disease.

*Key to grades:



    The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.



    Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

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  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration ().



    Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to . Selected references are listed below.

  • Bartholomew RE, Likely M. Subsidising Australian pseudoscience: is iridology complementary medicine or witch doctoring? Aust N Z J Public Health 1998;22(1):163-164.
  • Berggren L. Iridology. A critical review. Acta Ophthalmol 1985;63(1):1-8.
  • Buchanan TJ, Sutherland CJ, Strettle RJ, et al. An investigation of the relationship between anatomical features in the iris and systemic disease with reference to iridology. Complement Ther Med 1996;4:98-102.
  • Caradonna B. Western medicine looks at iridology again. Iridol Rev J 1990;2(2):13-14.
  • Caradonna B. Iridology research part 1-design. Iridol Rev J 1994;2(3):3-5.
  • Cockburn D. A study of the validity of iris diagnosis. Austral J Optom 1981;64(4):154-157.
  • Davidson F. How iridology and orthodox medicine work together. J Altern Med 1985;3(11):17-18.
  • Ernst E. Iridology: not useful and potentially harmful. Arch Ophthalmol 2000;118(1):120-121.
  • Friedman GD, Selby JV, Quesenberry CP, et al. Eye color and hypertension. Med Hypoth 1990;33(3):201-206.
  • Kleinstein RN, Seitz MR, Barton TE, et al. Iris color and hearing loss. Am J Optom Physiol Opt 1984;61(3):145-149.
  • Knipschild P. Looking for gall bladder disease in the patient’s iris. BMJ 1988;297(6663):1578-1581.
    View Abstract
  • Popescu MP, Waniek DA. [Improved irido-diagnostic method: possibilities of computerized iridology]. Rev Chir Oncol Radiol 1986;30(1):29-33.
  • Simon A, Worthen DM, Mitas JA. An evaluation of iridology. JAMA 1979;242(13):1385-1389.
    View Abstract
  • Worrall RS. Pseudoscience–a critical look at iridology. J Am Optom Assoc 1984;55(10):735-739.
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  • Yoo CS, Hwang WJ, Hong SH, et al. Relationship between iris constitution analysis and TNF-alpha gene polymorphism in hypertensives. Am J Chin Med 2007;35(4):621-629.
    View Abstract