I think in Dolphins, the visual sensing is ten times less than sound processing. Most dolphin species have a very sharp vision in and out of the water because the eyes can move independently which is enhanced by the curvature of the eyeball. They have a visual range of 180 degrees seeing forward, backward and sideways. They have no external ears, but they have small holes on each side of the head which conduct to the inner ear. They have 2 to 3 times more cells in the ear than humans, and therefore they can detect low frequency and high frequency sound waves as well as the tones of sounds.