I once heard that pirates wore eye patches, not because they had lost an eye, but rather because during a siege with another ship it was beneficial to see in the dark of the below decks. Therefore, a pirate would wear a patch over one eye and upon descending into the below decks would switch the patch to the other eye thereby eliminating the need to adjust their eyes to the dark. Is there any validity to this claim and/or were patches even all that common?
If you're new to the thread, please don't post the Mythbusters episode again. Mythbusters is entertaining but it's not history (or more specifically, it's not historical proof of anything.)
The short answer is no, not that we know of. /u/davidaop, our pirate expert, and I have both answered questions about this in the past. Unfortunately, because it's not a thing people did, there's not a canonical source saying that people didn't do it (if that makes sense); there's just an absence of evidence, into which void people throw half-baked conjecture. And Mythbusters.
I thought it was because the navigator in the crows nest was always looking through his scope and using navigational tools like a sextant. I thought continual use of these tools made you go blind in one eye for whatever reason. Therefore, this one particular pirate who happened to be the most seen one from the perspective of another ship, always wore an eyepatch. Covering the blind eye helped him focus with his good eye.