One of the most amazing things about human vision is the incredible range it has. We can see in very bright sunlight, and we can also see in nearly total darkness. Humans are built for living in the daytime and sleeping in the dark. The retina (the light-sensitive part of our eyes) has cells called cones (for seeing coloured light) and rods (for detecting movement and dim light). We have 20 times more rods than cones (120 million rods and only 6 million cones), yet we're still not very good at seeing in the dark. Hmmm... interesting fact.
There is one story I would like to share. You can share it too to others during night camping or campfire.
"Once upon a time, there lived two rival pirates, Captain RedHook and Captain Jack Sorrow. Both travelled far and wide throughout the open sea in search of the lost treasure, but only one had the treasure map. Captain RedHook took great care to protect the treasure map from Captain Jack Sorrow so that he might be the first to find the hidden treasure.
On a night much like tonight, Captain RedHook went below deck to study his charts and treasure map, believing he was now only a few days’ journey away from the treasure. What Captain RedHook did not realize was that Captain Jack Sorrow’s ship had been following him in the dark night, plotting to take over Captain RedHook’s ship and steal the treasure map.
At that very moment, Captain Jack Sorrow’s crew attacked, coming aboard the ship. Captain RedHook heard the commotion above deck, quickly hid the map and waited for Captain Jack Sorrow below. As soon as Captain Jack Sorrow came into the light, Captain RedHook blew out the candle, switched his eye patch to the other eye and used his night vision to fight poor Captain Jack Sorrow who was surprised by the candlelight and immediately lost his night vision. And that is why pirates wear patches."
Some assume pirates wore eye patches there to cover a missing eye or an eye that was wounded in battle, but in fact, an eye patch was more likely to be used to condition the eye so the pirate could fight in the dark. 😆😆😆
Important fact: The retinal used in the eye is derived from vitamin A. If a person's diet is low in vitamin A, there is not enough retinal in the rods and therefore not enough rhodopsin. People who lack vitamin A often suffer from night blindness -- they cannot see in the dark.
What Is Vitamin A?
Vitamin A actually is a group of antioxidant compounds that play an important role in vision, bone growth and health of the immune system. Vitamin A also helps the surface of the eye, mucous membranes and skin be effective barriers to bacteria and viruses, reducing the risk of eye infections, respiratory problems and other infectious diseases.
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