The desing of the eagle-eye
Eagles fly at an altitude of thousands of meters, in a manner similar to modern war planes, yet are able to comb the landscape below in staggering detail. The eagle can detect even the slightest of movements or color changes while in flight. It owes this ability to a very special eye structure.
In humans, the portion of the retina with the most acute vision is the fovea centralis, which has the highest concentration of cone cells. Eagles have two foveae, giving them an incredibly sharp sense of sight. Humans have only one fovea in each eye-for binocular, or forward vision. When we look at an object, both our eyes are directed toward the object. This allows our brain to merge both the images to create a sense of depth. The eagle contains a binocular fovea like ours, but also has a fovea for monocular vision that allows each eye to look sideways and see a separate image. So eagles can see both forward and to the side at the same time.
The eagle has a visual perspective of some 300 degrees, as well as an extra focusing power. Humans change the shape of their lenses to focus. But an eagle can change the shape of both lens and cornea. This gives it extra focusing power. It can also scan a 30,000-hectare (116-square mile) field from an altitude of 4,500 meters (14,700 feet), or spot a camouflaged rabbit from 90 meters (300 feet) with ease.
To attain this super-sharp vision, an eagle's retinal cells are tinted with special colored oil droplets, increasing the contrast for objects seen against the blue sky or green forest. Thanks to this, the eagle can spot minute changes in contrast from thousands of meters above and swoop down to hunt. The fact that a mere drop of oil makes this possible is doubtlessly one of God's countless blessings.
Flying is a miracle in itself. If one aspect of the present structure or position of a bird's wing were changed, it would be unable to fly. Therefore, it isn't possible for wings to have evolved over time.
As mentioned before, something else that couldn't possibly have evolved is the visual system. This is reinforced by the flawless nature of an eagle's eye. An eye with two foveae cannot form over time, as a result of coincidences. That second fovea was deliberately created to answer the bird's needs.
For an eagle, that droplet of oil in its retina cells is of staggering importance... But who made this fine optical adjustment? Did the eagle add
the oil himself, or on other animals' recommendation? Of course not. The eagles have enjoyed this feature from birth, for thousands of years.
So why are our eyes not as sharp as an eagle's? If human eyes contained the same features, they'd each be the size of a grapefruit. Moreover, humans don't need to spot a camouflaged rabbit from a kilometer away. This is why God gave humans their present eyes in a most aesthetic form.