Iridology is the practice of observing the markings on the iris in order to diagnose illness. An iridologist will analyse these markings and any changes in the appearance of the iris in order to pinpoint exactly where in the body (or mind) the problem lies. The iris is divided into various sections, each of which reflects problems in a specific part of the body. Roughly, the right side of the iris reflects the condition of the right side of the body, the left side of the iris reflects the left side of the body, the top half of the iris reflects the upper half of the body including the head and organs in the upper body, and the bottom half of the iris reflects the lower half of the body including organs in the lower body, the genitals and legs.
Iridology is a means of assessing illness, and not a treatment in itself. As such, an iridologist cannot treat a patient's disease, but can be valuable in determining the cause and nature of specific illnesses, which may not be evident otherwise. In many cases, complementary therapists (such as naturopaths or homeopaths) use iridology, in which case a course of treatment could be recommended. It is also important to note that such markings and patterns etc. do not indicate that the iris is infected, diseased or unhealthy itself at all, but is merely the "indicator".

Origins of iridology
Although reportedly practised since ancient times, the basic principles of iridology were published by a Hungarian doctor, Ignatz von Peczely, in the late 1800s. Noticing a link between his patients' diseases and the markings in the irises, Von Peczely drew up his findings in the form of eye charts or maps. The practice of iridology was brought to America at the beginning of the 20th century, and it was Dr Bernard Jensen, a chiropractor and naturopath, who formulated the more precise and accurate maps that are used by iridologists today.

How does iridology work ?
According to Dr Jensen's map, the iris is divided radially into 12 sections, each divided further into 10 subsections, giving 120 different areas which an iridologist will use to locate problems. The colour and constitution of the markings in the iris are also critical in diagnosing disease. Colour reflects the degree of damage to the tissue in the area concerned. This ranges from white for slight irritation or inflammation, through grey for mild, more serious conditions, and finally black, which is indicative of severe tissue damage. When there is disease or illness, holes form in the fibrous layers of the iris: the more severe the condition, the deeper the hole, which is why dark grey or black are indicative of the most serious conditions.

In addition to position and colour of the iris markings, the exact pattern is critical in determining what ailment the patient is suffering from. Whether the markings are arranged in rings, spokes or spots, radiate outwards, spread inwards or surround other areas of the eye, form within the iris or around its rim, and so on, are of absolute importance in diagnosing illness. It is this intricate examination of the iris which makes iridology such a precise analysis, allowing the practitioner to pinpoint the exact details of the patient's ailment - an experienced iridologist may even pick up problems which have not manifested yet.

It is not known exactly how patterns and markings in the iris are formed, or why they are reflective of the body's state of health. Some connect it with the fact that there are literally thousands of nerve fibres in the eye, making it a very sensitive area, while others suggest that the irises are affected by electromagnetic vibrations in the body.

What happens during a treatment ?
An iridology examination is not necessarily performed by an iridologist specifically. A good deal of doctors (especially homeopaths and naturopaths) will examine their patients' irises as part of their general evaluation. A specialist iridologist will conduct a longer and more in-depth examination the patient's eyes with a torch and a magnifying glass. Sometimes, a special camera is used to take a photograph of the irises and project it onto a larger screen for analytical purposes. Whichever method is used, the iridologist maps the markings etc. onto a chart to make a diagnosis.

These charts, together with photographs of the irises, can be used for comparison in future consultations, to detect changes in the patient's condition. Should the practitioner be a doctor, specific treatment might be recommended, otherwise the iridologist will advise a patient to consult his/her GP, once the nature of the problem has been established.

Who/what can iridology help ?
As a method of diagnosis, iridology can help anyone who is wanting to find out more about their state of health. Iridologists claim that any diseases can be detected in the irises, therefore there are not any limits as to who can benefit from it. It is particularly attractive to those who prefer non-invasive techniques, such as blood testing.