Visual acuity is defined as the ability to focus on images from a given distance, and is measured on the 20/20 scale. The human standard of “perfect” vision is 20/20. One with 20/20 vision can see clearly at a distance of 20 ft.
To put that into perspective, an eagle has the visual acuity of 20/5 – meaning that it can see at 20 feet what a human with 20/20 vision would need to be 5 feet away from to see. By this standard, an eagle’s visual acuity is 4 times stronger than ours. With the sharpest distance vision of all creatures, they are able to see and focus in on prey as small as a mouse from up to 3 miles away.
In addition to their unprecedented ability to see clearly at very far distances, eagles have near panoramic vision, a heightened sense of color vision, and can see UV light. While “good” eyesight is largely dependent upon a creature’s unique need for their specific habitat, by human standards it is safe to say that the eagle has the best eyesight in the animal kingdom.