How did cavemen and hunter-gatherers who were near-sighted survive? I can barely even find my shoes w/out my ?

They probably found other things to do closer to the cave. Found firewood, set up a defensive perimeter, tended the children, etc. The survival of the fittest mentality didn't really come about until the late 18th century. Prior to then tribes had more of a communal mentality and the old were looked to for their wisdom and guidance.