Human vs wedge-tailed eagle vision
Comparison and Contrasting
On the very top of the page, it can be seen that there are seperate sections comparing the eyes. Scroll down or press the buttons to start. Hopefully, by the end of your visit in the website, you would know the differences about the human and bird eye and cool facts about eyesight and vision.
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ABOUT THIS PROJECT
This project was done as a part of an eighth-grade science class. This project does consist of comparison of a healthy wedged-tail eagle eye and a healthy human eye.
Picture credit to Maria Khan
Picture credit to wikipedia
The Human Eye
Internal Structures
External Structures
The human eye is complicated, and needs external structures to protect it from nature. Below are the different external structures of the eye, and how they protect our eyes
From above the eye, the eyebrows have hairs that help protect the eye from dirt, sweat, blood, and rain. Underneath the eyebrows we come to the eyelashes. The eyelashes have touch-sensitive hairs that trigger a blink reflex when touched by anything. this helps protect against dust and bugs. Connected directly to the eyelashes, the eyelids come in. They are a protective layer to defend against dirt, dust, and debris. Beneath the eyelids, we find the corneas. The corneas are convex, transparent layer above the scleras, the irises, and the pupils. The corneas help lubricate the parts behind them, and they also lubricate themselves using aqueous humor. Looking at what's behind the corneas, the first thing one would look at are the irises. They do have pigment from melanin, after all. The irises help change the size of pupils, and are coloured differently depending on melanin levels. The less melanin, the lighter the eye color. What is in the center is commonly known as the pupil. The pupils are dark central windows for light to come in through to be processed by the internal structures. The scleras protect the entire eyeball, being tough, fibrous tissues that can hold together human eyes.
Starting from the back, we come across the optic nerve furthest back. It helps send messages to the brain that are proccessed by the retina; a thin translucent layer of tissue that has rods and cones for processing images and colors. The point where the retina and optic nerve meet is a blind spot. The retina does its job because of the choroid; a vascular layer between the retina, and the sclera (to be mentioned in external structures) that distributes blood into the retina, and branches off to other parts. The space in the eyeballs must be filled with something, or else the structure of the eyeball would collapse in on itself, and the parts of the eyeball would collapse. That's where the vitreous humor comes in. The vitreous humor is a jelly-like sphere that holds the eyeballs' shape, and holds the structures in shape. It has an egg-white consistency. Moving to the front of the eye, the ciliary muscles and the lens work together. The ciliary muscles are stringy muscles that change the shape of the lens which helps it focus on objects closer than 20 feet away. The lens itself is a convex, transparent structures that helps focus light into the retina to form an image.
The aqueous humor is a fluid that maintains the cornea (later mentioned in external structures)
The human eye is complicated, and it is made perfectly. Below are the different internal structures of the eye, and how they get our eyes to work
Video credit to makemegenius
The Wedge-Tailed Eagle Eye
Internal structures
External structures
The internal structures of the wedge-tailed eagle eye is similar to a human eye's internal structures, except it has some more features such as:
The two foveas that wedge-tailed eagles tend to have. Foveas are areas with a lot of visual activity. Having two foveas is the equivalent of a human looking through binoculars. To add to that, wedge-tailed eagles can zoom more because of the bony ring that elongates their eyeball, which gives it a closer look with surprisingly excellent vision. They, in fact, have eyesight so good it extends into ultraviolet and infrared bands. So if one were a wedge-tailed eagle, they could see the infrared signal from a TV remote. This also helps them see prey because infrared shows thermal. More advantages include having bigger eyes for a larger image on the retina, so even more zoom. The advantages are so great, that the wedge-tailed eagle happens to have the best visual precision of any other animals and birds. Their cornea and lens are angled towards their beak, and they have higher photoreceptor densities. It also has less blood cells to scatter light with, so it gets an even clearer image.
The External structures of the wedge-tailed eagle eye is similar to a human eye's internal structures, except it has some more features such as:
The bony eyebrows and the six total lashes that protect its eyes. Along with that, wedge-tailed eagles have a transparent eyelid underneath their usual eyelid.
The use for the usual eyebrows, however, is very different. The top and bottom eyelids help clean off and moisten the transparent eyelid underneath. The clear eyelid is to make sure the eye isn't damaged by weather.
The eagle’s eye is so acute, it can span into the ultraviolet bands. This type of light is not visible to humans because it has a shorter wavelength than visible light.
Video credit to Australian gold and silver Exchange