MadSci Network: General Biology |
Hi Daniel: Although I am not aware of any research in this area and have not read anything scientific about this, I will offer you my own theories as to why your eye colors may seem to change. My guess is that you have rather light eyes, either blue, green, or a mixture of both. It is true that some people's eye color can appear to change but I am not sure how much change can be elicited. My theory is that the iris ( the colored part of the eye that gives it its color), behaves in much the same way as a person's face does, especially a face with pale or light complexion. I am sure you have heard people commenting on another's face as being "really red". Well, there is a physiological explanation for this. The capillaries in the skin of the face become dilated, thus the percieved "redness". It makes sense that the more blood in your facial skin, the more "red" it would appear. As you know, the skin is semi-translucent, meaning some light can pass through it. Just look at your hand and you'll see outlines of "blue" veins. I am certain the capillaries of the iris works in much the same way. More blood in the iris capillaries will give its color a different appearance but exactly what color change, I am not sure. But it definitely is easier to tell when you have a relatively light colored iris. As you may already know, iris color is dependent on the amount of pigment in the epithelial cells of the iris rather then a difference in color. More pigment = dark or brown irides and less pigment = light or blue irides. Now back to the question of when your eyes color changes. Well, as you know, people's faces tend to get redder when they are mad or embarrassed, so it can be assumed that under these emotional situations, iris color may appear to deviate from its "normal" color. I hope the above has helped. I would offer a reference for this topic but I do not know where one exists! Anyway, good luck! Kenton L. McWilliams, O.D.
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