The shape of the fish's eye is designed for underwater operation.
Work Step by Step
The fish's eye has evolved to operate in water. That is, there is a certain amount of refraction that takes place when light travels from water into the fish's eye. The light speed change is from "light speed in water" to "light speed in eye". However, if the fish's eye were in air, then the light speed change would be from "light speed in air" to "light speed in eye". Light would be refracted more than it is normally, and the fish's vision would be blurry. The proposed goggles hold a water pocket against the fish's eye, and ensure that the light entering the fish's eye is coming from water.