Oxygen gets to your eyes via blood.
It is extremely unlikely, if not impossible, for soft lenses to get “lost in your eye”. This is one of those “scare your friends” stories that everyone hears but have no basis. The conjunctiva covers the entire white portion of your eye and the inner part of your eyelids. A soft contact lens could not penetrate it. Lenses could get lodged deep in an upper lid, but not behind the eyeball.