Toph is a tiny, girl who is the daughter of one of the richest families in the Earth Kingdom the Beifong family. She has been sheltered her whole life living within the walls of the estates, never allowed to leave.
Not surprised, I bet the animators paid close attention to how his eyes would reflect his environment and adapt to emotions like a normal person's eyes would.>> also he's the avatar and his elements are constantly changing, so his eyes could too
At first glance, Toph seems like a helpless little blind girl, but unbeknownst to her family (and most everybody), Toph is one of the best Earthbenders in the world. She is nicknamed the "Blind Bandit" and no Earthbender can beat her.