Tezuka was a total Disney junkie! In the "Essays" book it said he watched Bambi something like 80 times -- and he completely used Bambi's eyes on Astro Boy (note the shaded eyelids, brown color, long lashes). I think it actually amped up the "cute factor" that the Astro became a boy -- he's the most powerful thing on earth and he has heartbreakingly adorable puppy-dog eyes. The PERFECT foil!!
BTW I remember writing a letter to WNEW TV (Channel 5 -- NYC) with a drawing I made of a suggested new character for the series ("Astro Girl") -- and was completely FREAKED when Uran appeared after only a few months. I had designed her with a white blouse, short dark skirt, long dark hair in two ponytails and (of course!) jet boots. I was annoyed they cut back on her powers, but I remember screeching in complete joy to my parents "Look they read my letter and made Astro Girl!!!" I was one happy 10-year-old kid!
