The eagle eye is among the strongest in the animal kingdom, with an eyesight estimated at 4 to 8 times stronger than that of the average human.[1] An eagle is said to be able to spot a rabbit 3.2 km away.[1] Although an eagle may only weigh 10 pounds (4.5 kg), its eyes are roughly the same size as those of a human.[1] As the eagle descends from the sky to attack its prey, the muscles in the eyes continuously adjust the curvature of the eyeballs to maintain sharp focus and accurate perception throughout the approach and attack.[1]