Why Did Pirates Wear Eyepatches. — the assumption has always been that they wear patches to cover an injured or missing eye. They didn't say arrrr either.
However, in the world of piracy,. Hypothetically, if patches were used for preservation of night vision, that would explain why these famous pirates are pictured (on land) without them. And while some were an eye short, more often than not, pirates actually had perfectly fine vision in both eyeballs.