Iridology was first practiced in the 19th century by a Hungarian doctor named Ignatz Von Peczely. When he was a child, he nursed an owl with broken leg and noticed in its iris a black stripe that slowly turned white and the became tiny black spot as its leg healed.
Years later, as a doctor, he noticed a similar marking in the eye of a man with a broken leg. Over the years Von Peczely found many cases in which people suffering from similar illnesses had similar marking in their irises.