Why do pirates wear one eye patch?

Pirate is standing holding a drawn sword with a parrot perched on hand
| Photo Credit: Getty Images

Life at sea was difficult as the pirates had to know how to navigate every inch of their vessels during bright sunny daytime and pitch black night. An excellent night vision is necessary to battle the opponents and manoeuvre the large ships with windowless hallways and little lighting in pitch black. Have you ever wondered how they see at night? Making the most of their vision was the only way to travel discreetly through the night. According to historians, it’s the eye patches’ magic!

The wonder of science

Amazing as they may be, our eyes have a built-in delay while attempting to transition from light to dark. Because of rhodopsin, our eyes require 20 to 30 minutes to adjust to the night vision.

Rhodopsin is a biological pigment that is very sensitive to light. When one is in a perfectly lighted room and turns off the light, the pupil expands to let in more light. Even though their pupil allows in more light, it is insufficient for them to see in the dark. This occurs when the structure of rhodopsin in the rods splits into a few different compounds and sends a signal to the optic nerve, allowing their eyes to process even the tiniest light. However, in complete darkness, the chemical rhodopsin is not formed. It takes 10-30 minutes for the eye to recombine those molecules and restore proper vision.

An advantage to the pirates

Throughout history, pirates and other fighters had much experience fighting at night. After all, it was a tried-and-true strategy to surprise the opponents at night.

It could take too long for a pirate’s eyes to adjust if he was battling in the sunlight on the upper deck and had to move to the lower deck, which is generally dark, to continue the fight. Here is the science behind wearing an eyepatch! Pirates may “trick” their vision into adjusting to darkness faster by covering one eye with a patch and rhodopsin, which is still being made. They could flip the eye patch up for optimal vision once they were in a well-lit location or focused on their target. Pirates discovered the best of both worlds and the eyepatch became an important part of the modern pirate lore.