Eye

How big is an eagle’s eye? An eagle’s eyeball is almost the same size as a human eye. Given that the eyeball is so large relative to the size of the head, an eagle’s eyes fill most of the skull. Each eyeball is “fixed” in the skull, held in place by a sclerotic ring. Eagles are unable to move their eyeballs within the socket.

How far can an eagle see? Eagles use both monocular and binocular vision, meaning they can use they eyes independently or together depending on what they are looking at.

An eagle eye has two focal points (called “fovea” [singular] or “foveae” [plural]) one of which looks forward and the other to the side at about a 45 degree angle. These two foveae allow eagles to see straight ahead and to the side simultaneously. The fovea at 45 degrees is used to view things at long distances. An eagle can see something the size of a rabbit at more than three miles away.

Does an eagle see in color? Yes. Eagles can distinguish more colors than humans. They can also see in the UV range of light, allowing them to see the urine trail of prey.

What color are bald eagles’ eyes? Adult bald eagles have yellow eyes. Juvenile bald eagle eyes are brown and gradually lighten as they mature.

What color are golden eagles’ eyes? Adult golden eagles have brown or hazel eyes, occasionally with some flecks of gold and brown. Juvenile golden eagles have dark brown eyes.

Do eagles have eyelids? Yes they have an upper and lower eyelid, similar to ours, as well as a translucent nictitating membrane, often called the “third eyelid”. The nictitating membrane closes horizontally across the eye and provides moisture, protection and cleans the eye. See photo

Can eagles see at night? Yes, but eagles are diurnal predators who mainly hunt during the day and are typically inactive at night. However, wildlife cameras have shown adult eagles feeding on carrion and even bringing food back to the nest at night.

Of all the eyes nature has ever produced, those of the eagle — with its large, hooked beak, pale yellow iris and powerful talons — may be the most extraordinary.

Embedded on either side of its face, an eagle’s eyes give it nearly panoramic vision. If you were an eagle, you could see a rabbit running from three miles away. If you had an eagle’s ultraviolet light perception, you could track a tiny vole from the sky by the UV rays reflected from its urine.

And while most humans have 20/20 vision, eagles are blessed with an astounding 20/5 vision. That means that what looks sharp and clear to us at 5 feet is just as clear to an eagle from 20 feet away.

No wonder we use the term “eagle eyes” to describe superb vision.

So how does an eagle do it? How are its eyes like our own, and how are they different? Will technology and science ever help us catch up to the eagle and bring us our own version of raptor vision? Maybe so!

How good is eagle vision?

The eagle’s vision “is so far superior to ours that we can only try to imagine what their world must look like,” says William Hodos, an expert in bird vision and a distinguished professor emeritus at the University of Maryland.

Both human and eagle eyes are built like a camera with a lens, containing light- and color-detecting cells on the retina called cones.

In the center of the retina is a special area called the fovea where the cones are incredibly densely packed. The fovea in an eagle is like a convex, deep pit, according to Hodos, and in humans, it’s like a shallow bowl.

That depth allows eagles’ eyes to act much like a telephoto lens to capture images.

In a human, he explains, each fovea has 200,000 cones per millimeter. Not only do eagles have two foveae per eye, each is packed with a million cones per millimeter.

You might compare an eagle’s eye to a modern computer screen, with densely studded pixels giving extraordinary clarity and sharpness to every image. “Their central fovea is for close inspection,” Hodos explains. “Their lateral fovea is used more for distance vision.”

Eagle eyes are on the sides of their heads for a reason

Our eyes are on the front of our head, giving us excellent binocular vision but poor peripheral vision. We need both eyes in order to see a complete three-dimensional image.

An eagle’s eyes are more to the sides of the head. Though not as lateral as other birds, their eyes are fixed and unmoving in their sockets, angled 30 degrees from the midline of the face.

As a result, eagles have a 340-degree visual field compared to our 180 degrees. They are also capable of using binocular and monocular vision, and they see a three-dimensional world the way we do.

Eagles move their heads every five seconds

Eagles move their heads to the left, right or straight ahead every five seconds, according to a Duke University study. When an object is close, they are likely to look straight at it and view it head-on, but as it becomes more distant, they scrutinize it by turning their heads to the side.

Imagine turning your head to the side continually to scan the earth beneath you, and, after locating your prey, looking straight ahead and diving in for the kill.

Eagle eyes are big and beautiful

Though eagle eyes are the same size and weight as human eyes, an eagle usually weighs around 10 pounds. Comparatively, an eagle’s eyes are huge.

Many creatures, including birds, have droplets of oil dispersed into their cone photoreceptors in hues that filter and enhance color.

Birds, in particular, boast stunningly pigmented drops of oil in shades of red and purple.

These droplets intercept light, modifying its intensity and spectrum, and may protect the eyes from free-radical damage. At least one sunglasses manufacturer, Eagle Eyes, claims to have adapted insights from these findings into their products.

Eagles can see stunning colors we can’t

Hodos says many birds see more short- and long-wave light than we do — further into the red range at one end of the color spectrum, and all the way into the ultraviolet range at the other.

“They see colors as more vivid than we do,” he says. “They can discriminate more between shades. And they see ultraviolet light, but we have no idea what it looks like to them.”

All we know, he says, is that they see an absolutely beautiful world and that color differentiation is one of their great visual strengths.

Can humans have eagle vision?

While most of us have (or seek to have) 20/20 vision, humans are actually capable of even better visual acuity. Some Aboriginal people in remote Australia boast vision up to four times better than the rest of us.

When astronomers looked at Aboriginal descriptions of constellations from the 1800s, they needed binoculars to see what the Aboriginal people could see with the naked eye.

Olympic athletes in archery and sharpshooting are also said to have superior vision, with an average visual acuity of 20/16.

For those who weren’t born with such excellent sight, modern technology can help.

David Williams, the William G. Allyn Professor of Medical Optics at the University of Rochester in New York, worked with colleagues to pioneer the use of adaptive optics — the technique used by astronomers to take clear pictures of the sky through the earth's turbulent atmosphere — for the exploration of the retina’s organization and function.

They were able to identify tiny abnormalities in vision through a device called a wavefront sensor, and their work has helped ophthalmologists better perform LASIK surgery and cataract surgery and develop better contact lenses, often gifting people with 20/15 vision.

“We can look into the eye and see the retina more clearly than was ever possible before,” Williams says, “even allowing us to see individual cells in the living retina.”

One day, he imagines, “Someone will go into the eye doctor’s office and get a noninvasive procedure performed that will give them even-better-than optimal vision for life.”

Eagle Eyes’ Structure

Despite its small body frame of no more than 14 pounds (6.35kg), the eagle eyes actually weighed as much as human eyes.

While human eyes take up 5 percent of the head, eagle eyes occupy 50 percent!

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The shape of an eagle eye is also much different from that of us.

The back of the eagle eye is flatter and bigger, allowing a larger image to be formed.

Similar to dogs and cats, they have two eyelids. Other than the standard sleep-shut-eyelid, eagles have a special inner eyelid called nictitating membrane.

This eyelid blinks every 4 to 5 seconds and helps to lubricate the eyes and wipe off dust and particles from the cornea.

Eagle Eyesight

Eagle vision can reach up 4 to 5 times further than a person with perfect vision.

A perfect eyesight for human is standardized at 20/20 but an eagle eyesight has a visual acuity of 20/4, meaning that what you can see clearly at 20 feet, an eagle can see it with the same crystal clearness at 100 feet away.

See how they are able to spot the hare miles away?

How is it possible?

Firstly, their retinas are more densely coated with light-detecting cells called cones than human retinas, enhancing their power to resolve fine details just as higher pixel density increases the resolving power of cameras.

Secondly, they have a much deeper fovea, a cone-rich structure in the backs of the eyes of both humans and eagles that detects light from the center of our visual field.

“Our fovea is a little shell or bowl, while in hawk or eagle it's a convex pit. Some investigators think this deep fovea allows their eyes to act like a telephoto lens, giving them extra magnification in the center of their field of view," Hodos in Life's Little Mysteries's interview.

With eyes 8 times stronger than humans.. they scout the land for the slightes movement. for hours.

Eagle Color Vision

Eagle color vision also have an advantage over people in that people see three basic colors whereas eagles see five.

Eagle eyes have many sensory cells.

PBS notes that humans have 200,000 light-sensitive cells per square millimeter of retina, while eagles leave humans in the dust with about 1 million light-sensitive cells per square millimeter of retina.

They see colors as more vivid than we do, can discriminate between more shades, and can also see ultraviolet light — an ability that evolved to help them detect the UV-reflecting urine trails of small prey.

Like what is done in the video below

Eagle Field Of Vision

On top of the ability to see farther and perceive more colors, they have nearly double the field of view as compared to human.

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If our eyes are angled 30 degrees away from the midline of our faces like an eagle's, we will be able to see almost all the way to the back of our head with a 340-degree visual field (compared to normal humans' 180 degree field).

If you are eagle-eyed, no one will be able to sneak up and jump on you ever again!

Eagle Night Vision

You rarely see an eagle hunting at night because eagles do not have good night vision.

What helps them see more colors during the day hurts them at night.

Cones are a part of eyes that help eagles see better and see more colors.

Rods are parts of the eye that have to do with receiving light, and eagles have much more cones than rods.

Which is why even though they can still see in dark, they can't see as well as they do in daylight.

At night they will prefer to stay around their nests and relax as it is too dangerous and inefficient to hunt without their highly sophisticated day vision.

Genesis 6:8

Verse Concepts

But Noah found favor in the eyes of the Lord.

1 Peter 3:12

Verse Concepts

“For the eyes of the Lord are toward the righteous,

And His ears attend to their prayer,

But the face of the Lord is against those who do evil.”

Proverbs 15:3

Verse Concepts

The eyes of the Lord are in every place,

Watching the evil and the good.

Psalm 32:8

Verse Concepts

I will instruct you and teach you in the way which you should go;

I will counsel you with My eye upon you.

Luke 22:61

Verse Concepts

The Lord turned and looked at Peter. And Peter remembered the word of the Lord, how He had told him, “Before a rooster crows today, you will deny Me three times.”

Psalm 34:15

Verse Concepts

The eyes of the Lord are toward the righteous

And His ears are open to their cry.

Psalm 33:18

Verse Concepts

Behold, the eye of the Lord is on those who fear Him,

On those who hope for His lovingkindness,

Job 31:4

Verse Concepts

“Does He not see my ways

And number all my steps?