For any practical purpose, many pirates wore eye-patch?
There is a theory that pirates and other sailors wore a bandage on the eye for purely practical reasons. The fact that in the hold of the ship is very dark, and the descent to the deck of the human eye takes a few minutes to adapt. And if a sailor wearing a blindfold, he could remove it in the hold, and well just see one eye - this greatly increased the efficiency of its work in dangerous moments, especially in battle. While confirming its historical data does not exist, version looks plausible and has been verified by tests in our time. Documented a similar use of bandages at the dawn of the pilots of airplanes as they flew over the brightly-lit cities: they could look out of one eye and the other shall be exempt from under the bandage on the cards and devices in the dim cabin.