BACKGROUND:

Iridologists claim to be able to diagnose medical conditions through abnormalities of pigmentation in the iris. This technique is popular in many countries. Therefore it is relevant to ask whether it is valid.

AIM:

To systematically review all interpretable tests of the validity of iridology as a diagnostic tool. DATA SOURCE AND EXTRACTION: Three independent literature searches were performed to identify all blinded tests. Data were extracted in a predefined, standardized fashion.

MAIN RESULTS:

Four case control studies were found. The majority of these investigations suggests that iridology is not a valid diagnostic method.

CONCLUSION:

The validity of iridology as a diagnostic tool is not supported by scientific evaluations. Patients and therapists should be discouraged from using this method.