All birds of prey have very keen eyesight, which they rely on in order to find prey, but eagles are especially gifted in the visual department. By some estimates, eagles can see at least four times as much detail as humans. This is due to a few essential anatomical adaptations: large pupils that minimize diffraction, a ridge over each eye that shields sunlight and a higher concentration of cone cells in the eye. The result is incredible accuracy in locating prey, often at a distance of hundreds of yards. Hence we have the term "eagle eye" for people who display sharp vision.