From his autobiography I recall that his exceptional eyesight was a great leverage in combat. He spotted the enemy long before those in his formation did and long before German pilots spotted them. His vision was better than 20/20 or what might be described today as 20/15 which is rare in the general population. If a fighter pilot in ww2 can climb to a higher altitude undetected a shit storm awaits. Thus a surprise attack that an opponent never knew was coming. P-47 pilots knew the drill very well. I had the pleasure of knowing a P-47 pilot who flew missions in WW2. He had some interesting stories.
Here is a good documentary of a fighter pilots woes in ww2. If you don't want the full meal deal start at 27 minutes.
https://www.youtube.com/watch?v=FMGk_Fk_iJk