Metaphor of Storm:
In Act III, the raging storm is metaphor of turmoil inside King Lear. He overflows his passion with anger and begins to lose his sanity. His emotions catch him up just like storm catches him and he feels unprotected.
Metaphor of Gloucester’s Eyes:
His eyes were tortured and they were popped out. So he becomes blind while alive. His eyes metaphorically demonstrate the actual nature of his sons who were the cause of his blindness long before losing his sight. Just like King Lear, Gloucester seems to discern the things clearly after losing sight.