Although I never noticed in the main story of the anime, there are scenes in some of the openings where Zoro, Nami and Robin are shown wearing eyeglasses:
Is the fact that they all have bad eyesight canon? Or is it just some filler that the author probably wanted to mix into the series?
may be for appearance
like appearance while reading. Zorro is reading book and like some people use glasses to reduce the side effect while using computer and other thing which may damage the eye sight. – mirroroftruth Feb 19 '15 at 5:02