In the early 18th century, the Caribbean Sea was a veritable haven for pirates. In this lawless place, many merchant ships crossed the high seas with no protection from the authorities. This state of affairs was fully exploited by the pirates, who ushered in a golden age. Gradually, some stereotypical notions about pirates have formed, which are not always true.
Pirates did not walk the plank, rarely hid their treasure, and not all of them were criminals. Often, the life of a pirate was much better than most sailors from merchant ships and warships. But one notion of pirates is still true. Some of them wore eye patches. This image of pirates was common in the literature and movies of the last century. The most notorious sea scoundrels wore dark eye patches on one of their eyes. But why did they do it?
One plausible answer says that pirates were cunning and clever and did it when they needed to. The most common reason for wearing an eye patch is that they lost an eye during a battle. It begs the question why did they hide the intimidating ugliness under a blindfold instead of using it against the enemy? In addition, such many maimed sea robbers simply do not fit in the mind. Such an answer may not explain such many blindfolds among the pirate fraternity.
Another advanced hypothesis is that pirates wore an eye patch to create an adaptation of vision to darkness. They often had to go down to the lower decks to continue fighting after taking the upper deck. The human eye is designed so that in low light or at night when exposed to daylight, adaptation occurs fairly quickly. But after bright light, once in a dark place, it takes almost half an hour for the eye to adjust to the darkness.
The human eye has two kinds of nerve endings: rods and cones. Our cones sense daylight and color and are predominant over the rods, which provide us with night vision. The rods need only a small amount of light to provide vision, but they are less effective in high-light conditions.
Therefore, when light conditions change, it is much easier for cones to adjust and function than rods. Cones are not effective in dim light, and it takes much longer for the rods, which are in the minority, to take over their role. Humans are diurnal animals, so our vision is more receptive to daylight levels.
Indeed, it takes longer for human vision to adjust to sparse light is a fact. And it makes a big difference in combat when you have to move quickly from rooms with one lighting brightness to other rooms with completely different conditions.
Pirates, when boarding ships, would climb to the upper deck and then come down to finish the sailors who had hidden there. The same was true of their ship. When government warships stormed them, the pirate crew also had to go down into the hold to fight a defensive battle. As they moved to the lower tiers of the ship, the lighting got worse. Often, the descent was quite rapid, so it was difficult for eyesight to adjust to the darkness.
From all the above, the theory can be put forward that the pirates put a patch on one eye while fighting on the upper deck and then quickly took it off once they were below. Their eye under the blindfold was already adapted to the dark, so they could see their opponents well in the low light. This gave the sea robbers an advantage over their adversaries. The pirates could see their surroundings much more clearly than their opponents. This made it easier for them to strike deadly blows against their enemies.
However, any hypothesis needs confirmation. Certainly, from the scientific point of view, it is possible to close one eye to see better in the dark. However, there is no historical confirmation of this version, which would mention that this is the way pirates and other sea robbers fought on the ships. Nor is there archaeological evidence to support this assumption.
It is therefore difficult to see how this idea can be plausible. There is currently no evidence to support it. It also begs the question of why modern marines or pilots do not use this method of vision adaptation like the pirates. It would increase their chances of capturing an enemy vessel. Why might such a simple idea have occurred to medieval pirates but not to naval officers?
This theory has its detractors, who argue that a single-eye view narrows the field of vision, even in wonderful light, which can lead to the death of the pirate. But a pirate has both eyes open in the dark.
This idea that sea robbers, who held merchant ships in fear in the Middle Ages, wore patches over one eye to adapt their vision to the darkness while fighting below decks, is quite interesting from a theoretical point of view, which is scientifically valid. However, there is no mention of it in historical documents. Pirates did not like to write, they did not leave any written evidence after themselves.
Therefore, with the data available at the moment, it is impossible to refute or confirm this idea. Still, this theory about pirates wearing an eye patch is an important part of modern knowledge about pirates. The presence of a logical reason sea robbers covered one eye with a dense cloth can only enrich them.