Human eye have adapted to see clearly in the air, not underwater. When light hits the water, it bends, or reflects, in a way that counteracts the focusing effects of our corneas and lenses. Masks and goggles provide a barrier of air between our eyes and the water, resulting in clear vision. Unlike humans and other land-based animals, aquatic creatures evolved to see clearly underwater. The peepers of dolphins and alligators to double duty – they’re able to focus above and below the surface.
On land, the cornea and lens independently refract, or bend, light so that a collective image forms for your brain to interpret. But underwater, your cornea isn’t able to work in the same way. When submerged, the cornea is too similar in consistency to water, meaning there isn’t enough of a difference between the two for your light-focusing system to work as it should. Instead, the lens has to jump into action and make up for the cornea’s loss of focusing power.
Picture Credit : Google
