High Visual Acuity: Eagles have extremely high visual acuity, allowing them to see details at great distances. Their vision is estimated to be 4 to 7 times sharper than that of humans. This means an eagle can see an object from a distance of about a mile, which would appear as a blur to the human eye.
Large Eyes: The size of an eagle's eyes is quite large in proportion to its head. Their eyes are almost the same size as human eyes but are more efficient. The large size allows more light to enter, providing a brighter and clearer image.
Density of Photoreceptors: Eagles have a much higher density of photoreceptors in their retinas compared to humans. These photoreceptors (cones and rods) are responsible for detecting light and color.
Two Foveae: Eagles have two foveae (the part of the eye responsible for sharp central vision) in each eye, compared to humans who have only one. This allows them to focus on an object straight ahead while also keeping an eye on peripheral movement, which is crucial for spotting prey while flying.
Ultraviolet Vision: Eagles can see ultraviolet light, which is invisible to humans. This ability helps them track the urine trails of small mammals, making it easier to hunt prey that might be otherwise hidden.
Rapid Focus Adjustment: Eagles can rapidly adjust their focus, allowing them to switch from seeing objects at a distance to those up close with great speed. This ability is essential for catching fast-moving prey during flight.