The Vivacious World of VisionDid you know that you actually see things upside down, but when the information is sent to your brain it is flipped right side up? Can you believe that you can see fluent images while all these things are taking place without even a hesitation? But, there are many things that have to happen first in order for the brain to recieve information. To learn about the different functions that must be fulfilled in order for you to see, the different parts of the eye are talked about below.
12.The retina is in the back of the eye and responds to light, and then sends that information to the brain. Within the retina there are receptors, which consist of rods and cones. They "absorb" the light and later send the pictures to the brain. This is ultimately where the light is trying to arrive. But guess what? There is a difference in the two receptors. Rods are very sensitive to "light and dark changes, shape and movement." Rods don't really percieve color, but we use them in dim rooms and you'll see why soon. Also, there are about 120 million rods in your eye - a lot more rods than cones.
Cones however are sensitive to primary colors and not as sensitive to light. But there is a catch! Cones don't work very well in the dark, which is why you
can't see color in dark rooms.
Your next question may be, "Does that mean people who are color blind, don't have cones?" The answer is no, because color blind people can see color they just aren't able to percieve different colors from one another which means they don't have a certain type of cone or "one type of cone may be weak." (Below is a very detailed animation of how the receptors recieve light.) Games!Now that you know how your eye works, here are some games that can help excersise your eyes and improve the connection between your eyes and your brain.
To help: "Vision Perception"- the ability to "analyze, understand and interpret what we see." This can include "visual discrimination," "visual memory," "figure ground," "visual closure" and "visual form constancy". To find all the cool games on this website click here. This game requires you to use the skill of visual discrimination as you look for objects in order to find clues to solve a mystery in Hunstville. Videos!Watch this video to investigate what an image really is, how pictures are taken, learn about different types of images and investigate different types of optical devices.
Check out this video to see what you can do as an engineer using the world of vision (an optical engineer.) See how you can use optics to make things invisible, fight cancer, build astronomical tools, use light effectively, and create new technology! Find out all the possibilities!
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Awesome Links, Experiments, Illusions, and Videos for your eyesTake a look at a cow's eye! and see how it is similar to ours. At this link you can really apply what you've learned here on this website. Click here to see!
Click here to take an illusion test, how do you see and what kind of person does that make you? Go on cool and challenging illusion tours, click here. Want to try out some really terrific experiments? Click here to go to the page on our website. Do you know anyone blind? This site named, Not Fade Away, is a about a man and his journey into blindness. Want to make a self-portrait without a camera, click here. Lets continue talking about the parts of the eye. 3. The pupil opens and closes or dilates in order to let different amounts of light in. For example, your pupil is very big or dilated in a dark room in order to let a large amount of light in so you can see. In a bright room your pupil gets smaller because as you know your eye is very light sensitive and too much light entering could hurt your eyes.
4. The Iris is actually a muscle. It controls how much the pupil dilates, the Iris is also the colored part of your eye, it has that certain color because of pigment, which is also how our skin gets its color. Next, are three different parts of the eye: the lens (6), the
cornea (4) and the ciliary muscle. All these components control how the eyes see, they determine if you will be stuck with glasses the rest of your life, or have pristine vision, all in all they determine how the eye focuses (also determined by the shape of your eye.) The cornea will be discussed first because it is on the front of the eye. In order for the retina to recieve the light, three things must happen first: 1) The objects we are seeing must be minimized in order to fit into the retina 2)The eye must focus on what it is looking at 3) The scene that the eye is seeing must curve because the retina is curved The cornea does most of this by the proccess called refraction.
But, the lens and ciliary muscles help with this also. The lens is more of a "fine tuner." While the cornea does most of the adjusting to the images we see, the lens' shape can be changed with the ciliary muscle. The ciliary muscle does this in order "to change the precise amount of refraction the lens produces," states James Walker in his book Physics. This relationship is similar to that of the iris and the pupil. For example, when we look at nearby objects the lens has to be bent more or have more of a curve and therefore the ciliary muscles are tensed. This means that our eyes can get tired from reading for long periods of time or looking at close up objects such as a computer. Now you know why your eyes can get tired! The opposite also happens, when we look at distant objects our lenses are in the normal position and the ciliary muscles are relaxed. However, the cornea and lenses can only curve so much. If an
object is closer to the eye than it can focus it is fuzzy. The same happens if there is something too far away and the cornea, lens and cilliary muscle cannot focus, the image is also fuzzy. The lenses might not be able to focus because there is too much strain on the ciliary muscle. The inability of the cornea to focus is caused because of the shape of the cornea. The shape of the eye also affects this. The shape of the cornea (either too flat or too fat) along with the shape of the eye (either too long, or too short) will cause the image to be focused in front of the retina or behind it. In a person who can't clearly see objects far away (also known as nearsighted), the cornea is most likely too fat and/or the eye is too long, so the image will be focused in front of the retina. In a person who can't clearly see objects that are close up (also known as farsighted), the cornea is too flat and/or the eye is too short, therefore the image will be focused behind the retina. In the eyes of a person with normal vision the image would be focused right on the retina. Below are two depicitons of these disorders. Proper Names for Proper DisordersMyopia- Myopia is the scientific name for nearsightedness. If someone has this disorder, objects that are close can be seen clearly, but far away object appear blurry. This can happen if the eye is too long or the cornea has too much curvature. Because of theses factors the light is focused in front of the retina.
Hyperopia- Hyperopia is the scientific name for farsightedness. Hyperopia causes objects that are close up to be blurry, while objects that are far away are seen clearly. This can happen if the eyeball is too short or the cornea is too flat. Because of this light is focused behind the retina. Astigmatism- There are two types of astigmatisms - lenticular, and corneal. Astigmatism is a ruptured surface of either the lens or the cornea. For example, the lens or cornea would not be smooth, and they would have a flat spot, this would cause the image not to focus properly. Other Links and ResourcesTake this quiz testing your knowledge of the eye structure.
Take this quiz that tests your knowldege of the functions of the different parts of the eye. Check out this website for an interactive lesson on how the eye works. Here is another interactive lesson on how the eye works. You also might want to check out a video explaining how eyes work. Click here. Also, here is another video that goes more in depth with eye anatomy. |