The interesting thing about blue eyes

They don't exist.

Genetics have always intrigued me. It seems as though there are endless possibilities and combinations in human genetics. Who knows what you'll get, brown hair, red hair, blue eyes, green? It's amazing!!

So, when at four months I notice my twin boys' eyes are getting lighter and lighter in their shade of blue, it got me thinking about genetics and eye color. Then, once I started thinking about eye color I wondered what it was that made the different eye colors? Was it different color pigments, or melanin only, or what?  Soooo, I went a'searchin...

And this is what I found:  Blue eyes aren't blue!!  Nope, not at all.  It's a trick, a light trick. A sky trick, really.  Apparently the blue we see is not to dissimilar to the blue of the sky.  It shows light or dark dependent on how much light refracts or reflects and how much is absorbed, per say, into the eye!  I found this to be super cool.  Apparently irises have three layers: "a thin top and back layer, with a spongy layer in between called the stroma. " and the amount of pigment that gets laid down into these layers gives them their color.  Once melanin starts laying down pigment in our eyes, it can lay it on just the back layer of the iris, or the back and middle, or the back middle and front, and it can lay it down thick or sparse.  Now, how much pigment gets laid down is based off of genetics (although not strictly dominant or recessive as once believed).

Here comes my favorite part! As you could probably gather from what's written above, more pigment = more brown-ish eyes.  Less pigment = more blue-looking eyes. And what's really neat is that if you take a flashlight, and avoiding any light coming in at the eyes front-on, shine the flashlight onto the sides of the eyes as they are frontward facing, you can SEE the pigment!  : )  So, of course, as soon as I read this I had to try it out. All three of my children and my husband got flashlights in the eyes and my husband flashed me in the eyes. True to what I read, my brown eyed husband had TONS of pigment all through whereas my blue-eyed nine year old had barely as scattering of gold and my twin boys were completely bereft of any gold or brown pigment at all as far as we could tell.  My husband informed my that I had a barely-there scattering of color spots that looked like urine (his own words folks, not mine).  Super cool if you ask me.

Genetics are amazing.




*Side note: there is another pigment that can be present in the iris that is responsible for yellow tones in eyes. It helps out with greens also.