Eyeliner.
Yes real pirates wear eyeliner. But we're not talking Maybaline here. Real pirates don't wear that greasy, no run, make you look twenty years younger crap. Real pirates wear kohl. And the website linked above has real kohl eyeliner pencils imported from India and made with the traditional components used for centuries. If it was good enough 300 years ago, then it's good enough now!
The kohl is not just for looks, mind you. Though it does make some pirates (read me) look particularly dashing, it also serves the purpose of reflecting sunlight away from the eyes and helping to protect from anything floating in the air toward your eyes.
Other acceptable eye protection would be sunglasses. Colonial Williamsburg sells some very nice reproductions of a style popularized in 1750. You may have to spend some time explaining that to people when they accuse you of being a hippy, but no one will say that when you're in full garb.
This has been a public service announcement, we now return you to your regularly scheduled delusions of grandeur.
