Wednesday, May 14, 2008

Anatomical navel-gazing: The Eyes Have it (ha ha ha...no, seriously, I'm sorry, that's a tagline more appropriate for a dorko space-filling paragraph 'item' in Discover magazine, not a fine publication such as this. I apologize).

Today's lesson? "Central Heterochromia Iridis" (pull that one out at cocktail parties!)

When people ask me what color my eyes are, I've always said "blue," but the truth is it's a little more complicated. While most of my irises are blue, I have a central ring of hazel-brown around the pupil. I always assumed that everyone's eyes were that way, and didn't ask anyone about it (sort of like I once thought I was a genetic freak because my eyes appear to be different colors based on what I'm wearing...then half my friends said the same thing, and I felt like a spaz for thinking it was something bizarre and special). Turns out it's not very common...it's a form of "heterochromia iridis," which just means--break it down now--different...colored...irises. Seriously, label something in Latin or Greek and you can sell twice as much of it for three times the price. If 7-11 renamed the Big Gulp the "Macro Dipsia" and had people in white coats sell 'em they could charge five bucks. It's the mystique of the thing, and people act as though 'big words' are some kind of magical incantation...just like when philosophers or lawyers start talking about "post hoc ergo propter hoc" fallacies everyone goes quiet. Except other philosophers and lawyers, who are just pissed someone else busted out the Latin first.

So anyway, this is caused by differential deposition of melanin (the pigment that gives color to hair, skin and eyes...the more of it you have, the darker you are; albinos don't have any, which is why they're so pale) in the iris. Lighter colored areas, obviously, have less melanin than darker areas. In the case of central heterochromia, the rarest kind (yee haw, I am special) this can also be caused by the buildup of toxic substances (eek!). People with the central form are sometimes referred to as having "cat eyes." Thanks, Wikipedia! Oh, side note--people with Wilson's disease, a genetic inability to process extra copper in their bodies--can develop rings around their irises over time, too. These are called Kayser-Fleischer rings and can look like heterochromia except that, y'know, they develop over time, and if you have Wilson's disease you'll probably be having some issues with your liver (and other assorted organs...pretty much all of them, eventually) that will let you know there's a problem. So freak not.

I learned all this because I was plucking my eyebrows this morning and thought, y'know, in all this time I've never looked to see if this two-toned eye business is anything unusual. Googled "eyes two colors" and bam--Wiki be praised!

2 comments:

keepbreathing said...

My wife has the two-eye-colors thing going on too. Now I know why.

Anne said...

Cool, huh?