I've spent the past hour looking at my irises (or irides), just overwhelmed that I possess something this cool. The iris contains the muscles that adjusts the opening of the pupil to either let more light or less light enter our eye. When light is intense, the sphincter muscles that are around the edge of the pupil contracts, making the pupil smaller. When light is dim, the dilator muscles, which are embedded in the iris and that run medially through it like rays, allow the pupil to become bigger.
Yet, it seems that most people admire the color of the iris than the function. Some people have irises the color of blue, brown, gray, green, or a combination of these. I remember Michael from the VSAUCE YouTube channel brought out that these colors were due the amount of melanin (pigment) in the front and back layers of the iris. For example, people who have pigment only on the back layer of their iris would have blue eyes for the same reason the sky is blue. Those who have melanin in both front and back layers would have variations of eye colors. And those who have melanin in neither layer, like albinos, would have a pinkish color because of the blood vessels underneath. Cool huh?
So there I was just amazed with my irises, taking note of everything I can through a mirror. What if my irises had another unusual function? For example, can we extract more information from our eyes than just the quality of our vision? Simply, can our eyes tell us more about our overall health? For example, the yellowing of the conjunctiva, the soft clear membrane over the white part of our eyes, is a characteristic of jaundice, which often indicates a liver problem. We have also heard of diabetes causing blindness. So is it possible that our irises can be used to guide a medical checkup?
Iridology. I first heard the term from a friend who told me she visits her iridologist regularly. She said that iridologists were people who study the eye and predict health outcomes. I was so confused at that point. If I were so interested in ophthalmology, how come I had never come across this term? Was it another type of eye doctor? I was thinking of all the specialists that were vision-related: M. D. ophthalmologists, optometrists, D. O. (Doctor of Osteopathy) ophthalmologists, opticians?
As I googled the heck out of that term, I became so irritated with it. Iridology is the study of the fibers, color, shade, and shape of the iris to examine the health quality of the body and body's organs. Iridology is not generally accepted as part of medicine and lacks strong scientific evidence; so I immediately became anti-iridology. What if my friend were just wasting her time and money? What if she actually puts her health on the line because of a false diagnosis? How many people believe in this "quackery"?
I admit I was hasty with my judgment. After doing some more research, I realized that I misunderstood its purpose.
The purpose of iridology is not to diagnose illness or disease, contrary to what some articles suggest. It is more of a prevention route. For example, it might not be the best way to tell us that we have some liver disease, but it is meant to give us information about the activity of our liver, from which the iridologist can propose some overall health outcomes. So let's say that an iridologist accurately says that from his examination one of our body's organs may be underperforming in some way. We may take action by maybe changing our diet, exercising more, and planning a visit to a physician. In this way, we can prevent a disease from occurring which is a lot better than being cured from it.
It is good to note that iridologists are not medical doctors, but medical doctors and allied health professionals like nurses may use iridology as part of their practice. Iridology is considered by some to be part of the holistic approach to health.
There are not a lot of current research studies supporting iridology, which had led to my initial irritation. Nonetheless, I would also have to say there are not a lot of studies about it in general. The mechanism behind the method is not fully understood.
Iridology is not new; its practice actually dates back to ancient Egypt. On the other hand, modern iridology has a nice story behind it. Ignacz von Peczely (1822 - 1911) of Hungary always wanted a pet as a child. I'm not sure how old he was at the time he came across an owl with a broken leg; but I infer he was a smart little fellow, because he noticed a mark on the owl's eye at the time of the injury. As he helped nurse the owl to health, he became attentive to the changes of the owl's iris overtime. He also did the same with other animals. Later as a medical student and then doctor, he recorded the changes of the irises of many patients according to which ailments they had. He and contemporary Dr. Nils Liliquist made a chart of their observations.
Later Dr. Bernard Jensen (1908-2001) and other proponents developed more modern charts for iridology. These charts represent the left and right eyeballs, by the way.
So I look at this and ask, "What's the sense behind this?" It was really hard to find an explanation. When I did find it, it was from a page made in 2004 by a former iridologist, Joshua David Mather Sr. Needless to say, he lost faith in the practice to which he had at one point devoted his life. This was his reasoning behind iridology: The iris is composed of nerve fibers that somehow share the same nerve pathways with all organs and systems of the body. So when one part of the body is affected, the iris somehow reflects this. The pathway by which this happens is not fully understood or supported.
It didn't seem like a completely ridiculous idea to me. Our body is composed of systems of organs that work harmoniously. If one part is not working correctly, the other parts are affected. However, for the iris to be able to reflect changes from all our internal organs before we experience signs and symptoms is a daring theory.
I then came across an iridology-supporting site that suggested that the answer is in the nerve supply for the iris. The iris is said to receive information from one of the cranial (brain) nerves; and more interestingly, from one nerve in direct contact with the sympathetic nervous system (SNS: responsible for the "fight or flight" response). The nerve from the SNS branches toward the iris through the choroid of the eyeball (choroid: think lots of vessels). Then basically by virtue of SNS, the iris has information about the health quality of our organs.
The thing that irks me more is that those who read this site may think, "Great, that makes sense."- without their having any basic background about the eye. So let me throw some eyeballs at you.
Here's an eye.
Here's a basic eye diagram:
Look's prettier on the outside, doesn't it?
Light enters the eye first through the cornea. As you can see from the diagram, the cornea looks like a dome. What you don't see is that it's transparent. The cornea has a tear interface (film) which is really important. You know how light bends in water? Well, light bends once it goes pass the tear interface of the cornea to the anterior chamber that is filled with aqueous humor. We need light to bend to focus it as it enters the eye. One ophthalmologist noted that this tear interface on the cornea can be said to have more weight in vision than the cornea itself. The cornea cannot do its job perfectly without it. Isn't that cool? We bend light just by using our eyes. AND we can bend our finger. Beautiful.
The innermost part of the cornea is the endothelium. Underneath you see the aqueous humor which is a clear jelly-like substance. The aqueous humor nourishes the cornea and other structures in the front part of the eye and keeps them from collapsing inward (sort of like deflating). It also has some refractive index (bends light a little.)
Now we get to the iris. I previously said the iris controls the size of the pupil. It automatically contracts or dilates depending on the amount of incoming light. The lens further focuses the light with the aid of the ciliary muscle. The zonular fibers and suspensory ligaments of the lens connects the lens with the ciliary muscle.The lens becomes more dome-like when you are looking at near objects, and becomes flatter when you are looking at objects far away. The hyaloid canal allows this accommodation by holding fluid that can easily move back and forth as the lens adjusts light. This light is then focused on the retina, which is often compared to the film of a camera.
The retina contains photoreceptors called cones and rods. I should back up and say that light, or visible light, is a specific range of wavelengths sensitive to these photoreceptors. These photoreceptors convert these wavelengths into electrical signals. Although the photoreceptors respond in the same way to all wavelengths, the intensity of their signaling varies according to the type of wavelengths: short, medium, or long. There is a high concentration of cones in the fovea area, where your object of interest is focused. Cones allow you to process color and detail, while rods help you see when light is dim. The signals are further processed and sent through the optic disc to the optic nerve, where they are sent to the brain.
The sclera is the white hard shell of the eye. The vitreous humor is like the aqueous humor, but isn't continually replaced like the latter. It helps support the eye and keeps the retina pushing against the choroid. The choroid (between the sclera and the retina) is composed of layers of blood vessels, capillaries, and connective tissue. It is responsible for providing the retina with oxygen.
Okay, don't leave me here. Now that we know a little about the eye; let's get to the point of our concern: the iris, and this "nerve supply" the site had mentioned.
C would be where the muscle fibers of the iris are located. Remember when I mentioned way before that they controlled pupil size with the sphincter and dilator muscles? Yup, that's them. However, here the site was referring to the involuntary muscles that are around the margin of the pupil. So that would be the sphincter muscles.
D is the basement membrane which is composed of connective tissue and helps support the iris. E is the one of the 2 rows of pigment layer which prevent light from entering the eye through the iris. These seem to be the front and back layers I was talking about when I mentioned the variation of eye colors. The site didn't specify F and G, so I won't.
Bernard Jensen published a book in 1982 on iridology. He said that the sphincter muscles are mostly controlled by the parasympathetic nervous system (responsible for "rest and digest"functions of our internal organs). The dilator muscles are mostly controlled by the sympathetic nervous system. So this means that the activities of the sympathetic and parasympathetic nervous system affect the size of our pupil. So excitement or fear can cause our pupils to enlarge or contract.
He also said that the iris contains "over 28,000 individual nerve fibers," each which controls only about 10 muscle cells, which allows high sensitivity to changes from our body's organs by location. If you look at the chart below, you will see that each eye has specific zones that correlate to each organ. The brain is on top, just like with our body. The kidney is toward the bottom, for the same reason.
Iridologists say that the color of the iris tends to predict the type of health problems a person may have or develop. For example, people with blue eyes are said to have a higher likelihood for respiratory issues. People with brown eyes are said to have a greater possibility for blood and circulation problems. This part interested me, since I have brown eyes. Then I thought about Africans and African-Americans, and how they are very likely to have brown eyes. Sickle cell anemia is also common among these groups. However, I still don't see the science behind how color can predict this. A darker eye color (brown) is the dominant and more common genetic trait; so that is already a lot of people in general that are said to be susceptible to circulatory problems.
The shade of a certain zone in the iris is said to show whether an organ is over-performing (darker) or under-performing (lighter). The places that look like holes in the iris fibers are examined by iridologists and may have some meaning for them.
So I suppose the more important question is whether iridology works. Mather Sr. brought out the setbacks in iridology. An iridologist may use a type of light or camera to examine one's iris. Sometimes the lighting can change the way the color of the iris is perceived. Different degrees of light also affect the iris, since it is responsible for the opening of the pupil-another variable. The angle of the light can also cause different results. Mather Sr. revealed that even when there was a camera that accounted for these weaknesses, he saw no significant changes in the iris-especially in patients who have gone through "significant health changes," or have had organ impairments.
But you know what? Maybe Mather Sr. was just a bad iridologist? Although the science is not exactly there for iridology, maybe it works for other people. There was an article published in January of this year called "Iridology: Detecting impaired organ function with the iris." There were two studies that had two groups of people: one with blood pressure (BP) concerns, and one with no known BP issues. Iridologists were supposed to determine which people from both samples had BP problems. Researchers also tested for certain genes that may be associated with hypertension and whether the subjects tested positive for them. The results suggested a correlation between "iris characteristics" and hypertension. However, the sample size was too small to be able to use these studies as a backbone for iridology.
There was a study published in 1979 that found iridology's effectiveness at detecting impairments to be no better than chance. It failed in its supposed ability to detect kidney problems and was not "specific or selective." True, iridology is more of a prevention route and does not diagnose a specific illness. Another similar study was done in 1988, but with the focus on detecting gallbladder ailments. Same result: no better than chance. In 1996, researchers replicated the methods of iridologists using a computer to analyze the iris for certain disorders according to the given criteria. Yet again: no better than chance. Another study in 1999: same result. Researchers had determined that it is not a "valid diagnostic method." One article (2008) concerning iridology concluded that more studies need to be done. Although there have been little correlations here and there, iridology still has a large lack of scientific evidence.
Maybe Mather Sr. is right. Maybe what seems like a success for iridology is "purely coincidental." One part of me hates that it lacks evidence, but another part of me loves the theory. I want it to work, because it would be nice to detect an impairment which has not yet showed any symptoms before it becomes serious. How cool it would be to look at the iris and detect a cancer-related issue. I had to ask an ophthalmologist what he thought of iridology. After a few seconds of giggles, he said that it was all "hocus pocus." I inquired further and asked, "Let's humor it for a moment. Can the iris really tell what's going on in our body?" He responded that there are in fact certain diseases he sees that can cause some iris changes; but iridology's supposed ability to tell us the inner workings of our bodies is "hocus pocus."
After all my research, I'm going to agree with that ophthalmologist. I'm not completely against iridology, but I'm not going to waste my time and money on it either. More studies need to be done, and the science behind it needs to be more established. My advice would be that if you do decide to visit an iridologist, please only do it as a supplement to regular physician check-ups. You may even find a D.O. or a nurse who may practice iridology, and that would be even better since they have a strong science background.