If you grew up reading storybooks or watching movies about pirates, you know two things are true. First, they’re always searching for a treasure trove. Second, they wear eye patches. Since pirates are notorious for being combative — Shiver me timbers! — the assumption has always been that they wear patches to cover an injured or missing eye. But according to new theories, perhaps those parrot-friendly buccaneers were pioneers in tactical technology, not stealing treasure.
Some historians have an interesting perspective — that pirates wore eye patches to enhance their night vision. If you think about it, obviously pirate ships were dark, but can you imagine just how dark they must have been at night?
Life at sea
The reality of life at sea meant pirates had to know how to navigate every inch of their vessels during the daytime and nighttime to survive. In the dead of darkness, pirates had to be able to not only maneuver through their vast ships with windowless corridors and minimal lighting, but also jump from ship to ship in the dark. Plus, they fought battles with adversaries under the cover of darkness too.
Veil of darkness
There’s a theory that pirates and other warriors throughout history were well versed in nighttime combat. After all, surprising unassuming opponents at night was a proven method of success. Over time, swashbucklers who often found themselves embroiled in combat had learned how to adapt. Of course, the only way to move stealthily through the dark of night was to utilize your eyes to the fullest. By wearing a patch over one eye, pirates could “trick” their vision into adjusting to darkness more quickly.
Nifty night vision
Your eyes, while capable of doing amazing things, have a built-in delay when trying to switch from light to darkness. It actually takes 20 minutes for your eyes to adjust to night vision. One flash of light restarts the clock. This occurs because of the rhodopsin that naturally exists in your rods. Rhodopsin is a biological pigment that is extremely sensitive to light.
When you are in a brightly lit room and shut off the light, the first thing that happens is your pupil gets bigger (dilates) to let in more light. Even though your pupil lets in more light, it’s not enough to see in the dark. This is when the chemical rhodopsin in your rods splits into a few other chemicals and sends a message to the optic nerve, allowing your eyes to process even the faintest of light. Yet in total darkness, the chemical rhodopsin isn’t produced. It takes 10-30 minutes for your eye to recombine those chemicals again for proper vision.
So what does this have to do with pirates, you ask?
A tactile advantage
Well, the theory is that pirates discovered the best of both worlds. By wearing an eye patches at night, their eyes could adjust more quickly in the dark. Plus, rhodopsin was still being produced. Then, once they focused on their target or found themselves in a well-lit area, they could flip the eye patch up for optimal vision.
Avast me hearties!
You can test this theory for yourself to see if you agree. The next time you wake up in the middle of the night, cover one eye before you turn on the light. Find a target and then turn the light off and open both eyes. Perhaps you’ll notice that your eyes adjust to your target more quickly despite switching between darkness and light.