Iridology cholesterol ring. Conceptual computer- enhanced image of a human eye and an autoradiogram (fingerprint). Iridology is a complementary medicine that bases its diagnosis of diseases on an examination of just the eye. A cholesterol or sodium ring, appears as a white area (upper left) at the edge of the iris (brown). It is said to be indicative of either a high blood cholesterol or a calcium imbalance that may lead to hardening of the arteries. A DNA (deoxyribonucleic acid) autoradiogram is seen lower centre. It is the reading obtained from a person's genetic sequence, it can be used in medical diagnosis of certain conditions, such as hereditary high cholesterol.