My son has a lazy, and not sure its because of it but he loves to follow things out the corner of his eyes. For ex., he'll walk along a fence fast, looking at the fence while he walks straight not knowing what hes going to walk into. Even when in the house  he'll walk or run along the side of the wall and looks like he follows his shadow while he goes along. Has anybody have an idea on why he does this or if it is a sign of something.