Well, Toto did it again last night and broke skin.

He was fully awake! I don't get it. He bit me on my big toe and my index finger. My toe actually bled pretty good, and my skin is rough on my feet. What gives?
ETA: His eyesight is good as far as I can tell. He is a crazy ball fanatic and goes after his ball so fast and reaction time is really fast so I think he can see well.