So if you don't know this one thing, you don't read enough CLAMP: messed up eyes are a must.Left and right (no pun intended), eyes get gouged out, blinded, change colors, look nightmarishly freaky... Some examples: Seishirou goes blind in one eye, Subaru then loses an eye to compensate (not that he has serious issues or anything). Fai's eye gets eaten, Syaoran's clone then gains a freaky blue eye. Kamui's eyes neevr seem to be the same color... are they red? Blue? Purple, brown, gold? Depends on the picture! Perhaps today they'll be chartreuse! It's like you can judge how screwed up the character is by the screwiness of their eyes. So what do think? Is it the old "eyes are the window to the soul" thing? Or something else that invokes a deep seated eye fetish in the hearts of these manga-ka?

You are forgetting Wish, where a demon gives an eye to a angel as a kind of marriage contract, and XXXholic when after a spider eats Watanuki eye (the main character) Doumeki (his... let's call him, friend) gives the half of his, to avoid Watanuki going blind of one eye.

Well, they must have some kind of fetish; although at some interview, I think they joked about that, saying it was because they (Clamp) had bad eyesight.

I knew there were others, but I haven't read as much of Wish and xxxholic as I'd like. Need to do that. Yes. *dives into pile of CLAMP*

Eyes...rather than a fetish, I think they simply see the eyes as the symbol of a self changing. They love the idea of doubleness, or multiple selves: there was X, and now TSUBASA. So I guess the changing of the eyes' condition is for them symbolizing their characters' radical change. Look at Fye, Syaoran, Watanuki+Doumeki...all of them changed completely after something happened to their eyes. Fye is no longer fooling himself (with the help of Kuro-sama, of course), Syaoran (both) either lost himself or found himself again, Watanuki no longer thinks sacrificing himself blindly for others is good, and Doumeki...well, he chose to relate himself to Watanuki and everything about him (including Yuuko-san's shop, in which he couldn't enter at first).

Although sometimes I think they change the eye colour just to make their fans squeal XD

Probably a bit of an emphasis on 'the eyes are the windows to the soul' thing... and you know how anime/manga like to emphasise the eyes as being the most expressive part of the face. I mean, why else would the damn things be 1/2 the face?! XD

I think they want to demonstrate some drastic change in the characters' personality when they change their eyes. There are many examples listed above, and I'd want to add one more thing. Usually, when someone in CLAMP's manga loses an eye, that manga's plot turns a lot more serious and dark.

^agreed. In fact, my friends and I are pretty much fond of saying "In CLAMPLAND, everything's fun and games until someone loses an eye."

Whoa, never have really thought about those eye stuff so much..but now that you mention it. I never really think anything so deeply, so I'm always amazed that people notice stuff like this! Do you think there will be an eye issue in Legal drug when it comes pack from hiatus (hopefully)? Now I think there will..

Curse CLAMP and their hiatuses (hiati? gah). Curse them.
I wouldn't be surprised if it did. It's right up there with cherry blossoms and Tokyo Tower in the CLAMP symbolism favorites.