I think pebbles are a problem for him bcos they can easily move through various outside interaction, which would mess with him walking with the way he perceives his surrounding with magic (I imagine it's like how bats use echolocation)It doesn't even make sense, if he can even read paper then wtf is he missing? Just long distance sight? And why in the other chapter he says pebbles and stuff are a problem but somehow text which is flat isnt. Being blind is basically irrelevant to the story and making a magic eye is almost dumb at this point.
text doesn't move, and it wouldn't mess with him walking