The holistic concept of alternative medicine is that each part of the body, if examined correctly, will tell you what you need to know about the other parts of the body. For instance, in Chinese medicine, a lot of time is spent on examining the pulse and nerves, and in Chiropractic, a misaligned spine is a diagnostic part of treating diseases.
Iridologists see where changes in the iris indicate the onset of disease when certain markings and colour changes appear within the eye. Iridologists contend that signs of degenerative diseases are present in the iris well before reaching other organs, and therefore treatable at the earliest stage possible. They do this by enlarging a photograph of the eye and charting changes in the minuscule thin membranes. Some iridologists can even figure the exact area of the body that is sick by the position of the lines in the iris, but others don’t believe the science is that exact.
However, American iridologists in particular, believe that as the eyes are connected to the brain, that it would make sense that they are a kind of a switchboard, (thousands of nerve endings make up the iris) which along with providing sight, has the ability as well as the responsibility of catching diseases at the very beginning.