Touch Electric Fields Water has different properties than air. Visibility in air is normally measured in miles. Visibility in water ranges from less than 1 inch in turbid water to around 100 feet in very clear water. Electrical conductivity of water is much greater.
All vertebrate eyes are structurally similar.
The principal differences in fish eyes relate again to the medium. The lens has a high refractive index and functions as the single focusing element. A fish lens is spherical and is not changed for accommodation. Instead the lens is moved closer or further from the retina. Fish do not have necks, nor can they turn their heads to look in different directions.