I would like to relate an anecdote, not based on science at all, of what happened to me when my mother took me to a brother who was an iridologist. I can't go into too many details in this public forum because it would risk exposing someone. Here is what I can say. Being a very private person as a teenager, I was reluctant when my mother dragged me to a health food store to see this brother, who was an iridologist. Several members of the congregation were present, mostly sisters. I read some literature on iridology given me and became very concerned. According to the brochure, an iridologist could look into your eyes and diagnose many things about you. Being a private person, I was very concerned about what this brother, a perfect stranger, might find out about me. Would he tell my mother about the things he saw? Would he tell the other sisters? Would he tell the elders? I was mortified!
When it became time for him to look into my eyes, I kept glancing away. I had psyched myself out so badly and was so nervous that my innermost thoughts and secrets would be exposed, that I couldn't look anybody in the eyes, including my mom and the sisters. He did my reading, diagnosed several ailments that I was having, and recommended some supplements, etc. I was so happy to get out of there.
I met him again years later after I was DAed for about a year. If my mother knew the circumstances of that she would just die! But that's another story. I started talking to him about meeting him before and all of the sudden he remembered me. "You're the one who kept looking away." I blushed and said "Yes, because I was afraid you would see something in my eyes that would embarrass me in the congregation." He remarked, "Yes, I did see that in you, but whenever I did see it in someone, I never said anything to anybody." Thankfully he believed in confidentiality between a physician and client over revealing secret lives to the elders.
So is it provable science? No. And I am still very leery of alternative medicine, having had so much of it forced upon me over the years, but in this case I have to keep an open mind because of what personally happened to me. He definitely knew my secret.
I think the body is a very complex thing. If our fingerprints and DNA are completely individual to us, then why not our irises as well? I would like to see more research as to what is real provable science and what is not. They say that they can detect the genetic predisposition of diseases within the DNA now. Can they also see specific traits? Will they be able to take DNA from a crime scene someday soon and determine if that person is a super-taster who might be found frequenting Mexican restaurants, for example. Will they be able to determine a person's other predilections? Smoking, alcohol, sexual orientation, spicy foods, bland foods, lactose intolerance, incontinence, etc.
I imagine so. And maybe someone will prove that the irises reflect certain ailments. I don't know. All I can say is that a lot of times what appears to be superstition ends up being science that we just didn't understand yet. Germs were just a theory until they were proved under a microscope. Several hundred years ago nobody imagined catching a murderer by examining fingerprints. Lightning wasn't electricity to ancient people; it was the wrath of god.
So I am skeptical about these things, which means that I reserve judgment until it is proved to me one way or another. Iridology may become a proved science one day. I certainly consider it a possibility, but I don't think I would put much money into it today.