This eagle's intense stare, as it watches it's surroundings, is mesmerizing. 

The eye's size and shape give the eagle magnified vision, and special receptor cells in the back of the eye give it amazing visual clarity, allowing an eagle to spot a fish 2 or 3 miles away. 

This combination of magnification and visual clarity allow an eagle to see objects with 8 times more clarity than humans. 

This is where the term "eagle eye" comes from!