only out of the corner of your eye

"There are faint stars in the night sky that you can see but only if you look to the side of where they shine. They burn too weakly or are too far to be seen directly, even if you stare. But you can see them out of the corner of your eye because the cells on the periphery of your retina are more sensitive to light. Maybe truth is just like that. You can see it, but only out of the corner of your eye."
Edge 165: