Believe it or not – Pirates didn’t wear eye-patches because they had an eye missing.
Yes, you read that one right! Those trademark pirate eye-patches are nothing to do with a missing eye, but rather to see better in the dark.
Okay, now stay with me for this one – when transitioning from a bright and well-lit area to a dark area your eyes take some time to adapt to the darkness. This is called dark adapting, which can take up 25 minutes to occur when transitioning from extreme light to extreme darkness.
Pirates would often move above and below decks, so by wearing an eye-patch they’d have one eye constantly dark adapted, meaning when they went below decks they could just switch their eye-patch and their sight in the darkness would be far better than someone with no eye-patch and no dark-adapted eye.
If you don’t believe me, when you go home later turn the lights off in one room of your house and cover one eye with your hand whilst you’re standing in a light room. Go into the dark room, uncover your eye and you’ll notice just how much of a difference this will make compared to just walking into a dark room from a light one normally.