Vision Underwater: 4 Common Questions

The eyes house some of the most active, fastest and smartest muscles in our body. Did you know our eyes require us to use half of the brain in order to see? Our eyes are pretty impressive! Like the way our eyes  adjust in order to see in a dark room, or the fact that they are capable of healing from a cornea scratch within . As impressive as our eyes are, they do have their weak points, and seeing underwater is one of them. You’re probably familiar with the irritation that comes from opening your eyes underwater. This is because they aren’t meant to be opened underwater. Yes,  the eyes are capable (still impressive) but it’s not recommended by your eye doctor. We’ve picked out 4 of the most common questions about underwater vision. Take a look. 

  1. Do sea animals have better vision than humans underwater?

There is no clear answer to this question. Some fish located deep on the ocean floor may have poor vision or no eyes at all, while others have the best vision in the world. But one sea animal that has very comparable vision to humans is the shark. So much so that shark corneas have been used in replacement surgery in humans. However, there are some differences. For example, some sharks have 360-degree vision, humans, as you know, do not. One of the most interesting things about shark vision is they have a nictitating membrane, also known as a third eyelid, which provides a protective barrier over their eyes without impairing their vision. 

  1. Why is it so hard to see underwater?

There are several reasons why it is so difficult to see underwater. One being that if you are swimming in a chlorine-filled pool or a salty ocean, the eyes can become irritated and red causing your vision to worsen. Objects can also magnify underwater and can appear up to 25% closer than they are. Another reason humans can’t see well underwater is because water absorbs light, quickly reducing the amount of light and resulting in dull, monotone colors.   

  1. Can we train our eyes to see better underwater?

Yes, we can train our eyes to see better underwater. Just like walking, riding a bike, or learning a new language, training your eyes to see underwater can improve your vision underwater. Although studies show that only children can be trained to see underwater. According to a study conducted by Anna Gislen in South-east Asia, she found that adults could not see as clearly as children underwater. 

  1. Is it bad to open your eyes underwater without goggles?

Eye doctors recommend wearing goggles to anyone planning on opening their eyes underwater. Even in chlorinated pools, there is risk for infection and the chance the  . Additionally, after a long day at swim practice or the pool, the eyes can become irritated and red. Increased exposure to irritants or chemicals may cause your eyes to become irritated. In a VSP Blog post, Dr. Arthur Kobayashi, OD a VSP network doctor—and avid swimmer—on the North Shore of the Hawaiian Island, Oahu says, "Red eyes occur when blood vessels near the surface of the eye become enlarged and dilated," Additionally, Dr. Kobayshi recommends that contact wearers should never open their eyes underwater, "The water could damage your lenses—they could change shape, rip, fold in your eye, or even get washed away." The possibility of bacteria contaminating your lenses and causing eye infections also exists."

We hope that the answers to these four questions has been helpful to you. If you think you may have injured your eyes while swimming, contact an eye doctor to schedule an eye exam.

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