Weakness in body tissues or organs often show up in the eye before they show up in medical tests. An iridologist will map out a person’s eye and compare this chart to the iris charts developed by the founders in the 19th century. A complete iris analysis will show whether a person exhibits a generally good constitution or a poor one. The patterns, structures, colours and degrees of lightness and darkness in the iris tell the iridologist if you have any irritation, injury, over-activity or degeneration of the tissues and organs.