Little League Baseball (from the majors division down) doesn’t allow on-deck batters for this very reason. This kid is hit in the eye/helmet (not sure which) by a wicked foul ball as he’s taking his warmup swings. These kids look to be Little League age, but it must be another sort of league. Since the victim is moving, we have to believe he probably got hit in the helmet.
But even when you take a foul ball to the helmet, the results can be painful: