You may or may not have noticed -- it's a subtle sort of thing -- but there is a definite eye motif running through the manga and anime world. Examples aren't all that common, but when they show up and you know what to look for, they're unmistakable.
I'd originally chalked up the eyes as an homage to Tsuge Yoshiharu's psycheldelic nightmare Neji-Shiki ("Screw Style"), a Sixties gekiga classic. In one scene, the protagonist limps through the streets in search of a doctor to mend a severed artery, only to find the town filled with nothing but opthamologists.
(As an aside, Toho tried to hire the notoriously reclusive Tsuge to create the animated sequences for Godzilla vs. Hedora. He refused, but it's interesting to speculate just how much MORE demented these segments would have turned out with his participation.)
Anyway, there's what appears to be an homage to this in Michael Arias' 2006 Tekkon Kinkreet, where the outcast yakuza Kimura drinks his troubles away in a strange bar:
There's even what appears to be a subtle tip of the pen to Tsuge in Studio Ghibli's "Spirited Away." A mysterious eye doctor can be found in the ghost-city surrounding the spa:
But the question is, where did TSUGE get the the original "eye-dea"? (Oh, I slay me.) While watching the newly restored full edition of Fritz Lang's 1927 sci-fi classic Metropolis last night, I was struck by a sequence portraying "evil Maria's" bewitching influence on the male population of the city:
Inspiration? Coincidence? It's been 20+ years since Tsuge last drew a comic, and given his legendary reluctance to speak to interviewers we'll probably never know if he was channeling Metropolis. Whatever the case, keep your eyes peeled next time you're enjoying your favorite anime or manga. Blink and you'll miss them, but the eyes are there.