Still not enough geeky / bookish Halloween costume ideas for you? Jennifer Chang on YouTube has several reviews of their contacts, and shows how their lighter blue and green lenses can still be seen on darker-colored eyes. Makeup artist and cosplayer MakeupMadhouse has a great video showing off Coloured Contacts lenses and how to properly put them in. They have recently come out with UV contact lenses that glow in UV light, which would be perfect for a Danny Phantom cosplay.
