Something got into your eyes. You lower your face in a bowl or sink of water to wash out that irritant. Your eye stings. You feel uncomfortable. You wonder - why does it hurt? Is it because of chlorine? How about seawater? How can some people comfortably see underwater without goggles?
Our vision is blurry underwater unless we put on swimming goggles. Children of the Moken people, a tribe found deep in the island archipelagos on the Andaman Sea, and along the west coast of Burma & Thailand have unusually good underwater-vision. What are these abilities? Is it adaptation or acquired through practice?
Credit: Wikipedia Commons
The Human Eye
Our eyes are made to allow it to focus only on a specific angle of light - the angle that light bends when it travels between air & the eye. The part of the eye that allows us to focus on different things is known as the lens - it changes shapes so that we can focus on objects at various distances.
Credit: Wikipedia Commons
However the eye cannot focus correctly when light travels between water & a person's eye because the light is bent at an incorrect angle. This is why we have blurry, unfocused vision when we open our eyes underwater.
Children of the Moken people
Anna Gislén of Sweden's Lund University investigated the unique ability of these children. She discovered that they could make their pupils smaller & change their lens shape (i.e. to accommodate or muscularly change the shape of the eye's lens to increase light refraction) for them to see underwater.
Schematic diagrams of pupils underwater: The Moken child’s pupil (left) is smaller than that of a European child (right)
When pupils are constricted, vision is further improved. This is similar to the process that improves focal depth if using a camera with a smaller aperture.
Credit: YouTube/BBC One
Can an adult see like the Moken children?
Scientists believe the skill isn't a genetic trait but something that is acquired with practice – any child could learn to have such extraordinary vision. Anna Gislén tested with some European children & found that they were able to do it but not as well as the Moken children. Does this mean adaptation played a part?
When we age, our lenses become less flexible. That’s why adults lose the ability to accommodate underwater, and just like the Moken adults, we won’t be able to do this. Give it a shot!
Note:
There’s an alternative way to see underwater without having to manipulate your lens.
Check this website: How to Open Your Eyes Underwater without Goggles on and Not Hurt
Shared by Azni Zainal Abidin
Guest Blogger
No comments:
Post a Comment