How Do We See? Mind-Blowing Kids' Facts On How Your Vision Works! | Kidadl

FOR AGES 3 YEARS TO 18 YEARS

How Do We See? Mind-Blowing Kids' Facts On How Your Vision Works!

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A certain amount of light passes through the retina, which is present at the back of the eye, then into the optic nerve and subsequently to the brain for processing visual information.

The information from the retina in the eye is transferred to other areas of the brain via the optic nerves in the form of electrical signals, which are then processed to allow humans to see. But we don't 'see' with our eye; instead, we 'see' with our brain, and the amount of light takes time to get there.

At least 70 milliseconds have occurred between the time light strikes the retina in the eye and the signal is well along the brain circuit that processes visual information. These next visual sections are fantastic, but you won't be able to view them with your own eyes! Doctors examine the inner workings of a visual eye, such as the lens, with sophisticated microscopes. After passing through the pupil, light strikes the lens. The lens is transparent and colorless and rests behind the iris. The retina is a layer at the back of the eye that contains light-sensitive cells that send nerve impulses via the optic nerve to the visual cortex in the brain which is present at the back of the brain and is a part of the occipital lobe, where a visual image is produced in the eye.

It is said that our eyes work as a camera. Now for the camera to capture a picture, the light passing in a straight line should fall on the lens and reach the back of the camera. This concept is similar to the structure of our eye.

For example, you focus on taking a picture of a tree, the sunlight bounces and reaches the lens. The lens then allows the light to fall onto the back of the camera. As the area of the lens is smaller than the area of the object where the light goes, this light creates an upside-down picture. And so does the retina. The images perceived by your retina are upside down, it is the brain that converts the information so we see the world in the right way. So we can say, we see through our eyes but the brain translates what we see into useful information with the help of lens. Now, do you ever wonder if we see the world in 3D or 2D? Or how do we see different colors? Find out by reading the rest of the article! After you are done reading about how different parts of the eye like the lens, cones, pupil, iris, optic nerves, and cornea work together in the eye to help us see objects, do check how do we see color and how do neon lights work?

How do we really see?

The structure of the human eye is very complex and scientists believe that it has evolved from a simple light-dark sensor in over 100 million years! The vast majority of the cone cells in the human eye are located in the center of the retina. We also know that our eyes work very similarly to a camera.

We know that the light enters the eye and what we see is flipped. We are aware that there are sensors that are sensitive to light in cameras. These sensors collect small bits of light through the camera and collect them to create a picture we see.

This vision cortex is situated in the back of the brain called the occipital cortex or lobe. Through the coordination between our eyes and brain, we are able to see.

Fact: the human eye contains three types of cells that can perceive millions of different colors we see every day. Some animals have more than 12 different cells and can see more colors.

What can humans not see?

Eyes are the smallest organ located in our body, yet it consists of more than 100 million cells called rods and cones, inside the retina itself that respond to light. Human eyes have the capability of visualizing all the colors of a rainbow after they have been reflected by a medium, even though these colors are spread across an extremely small range of wavelengths.

We see the world through color and lights. As Sir Isaac Newton suggested through an example, that if a light ray is passed through a prism, it is broken into distinct wavelengths. It separates white light into different wavelengths and into- what we call the colors of a rainbow- violet, indigo, blue, green, yellow, orange, and red.

Depending on the properties of an object, some colors are absorbed while others are reflected. For instance, white is the result of one or two mixtures of colors of light. Therefore, visible light is also called white light. On the other hand in black color, the wavelengths are missing. As a result, all objects in a dark room will appear to be dark due to the absence of visible light.

Now there are lights that humans cannot see. They come in many colors like radio, X-ray, ultraviolet rays, infrared. Our body also releases infrared light and it is present around us but as it is too red, our eyes are not able to see it. Then X-ray light is of blue color but it is too much blue that our eyes are unable to see it.

Do you know that some amount of red light can help reduce wrinkles and blue light wavelength can help in the regulation of our sleep cycle?

The lens, cones, pupil, iris, optic nerves, and cornea are different parts of the eye that help us see different objects.

Do humans see in 3D?

Hold a finger at your arm’s length and look at it through one eye, then through the other. Do you see the images jump? This is how 3D vision works. It is because of binocular disparity. Binocular disparity is one of the most crucial pieces of information the visual center of the brain uses to reconstruct the depth of objects or images.

We are 3D creatures in a 3D world but our eyes can only show us two dimensions. Our brain has the ability to put together two 2D images in such a way to show depth. Our eyes are separated on the face, where each retina produces a slightly different image. This difference is a direct result of the depth of the object. When we see two images, they are assembled in our brain. They are then interpreted as depth.

How far can human eyes see?

Do you ever wonder how do we see something at a distance? Considering many factors that affect eyesight, the sight of a human eye can see pretty far.

When we are standing on the ground there are various factors that can affect how far we see. It can be your eyesight and how well the eye functions about your sight. It also depends on the object you're viewing and the curvature of the Earth. It can also affect if there are any obstructions in your line of sight. Experts consider a normal vision to be 20/20 vision which means that you can see something that is 20 ft (6 m) away from your line of sight.

As we have read that to process an image, some series of actions between the eye and brain have to take place. The light reflects off an object through the cornea. Which in turn bends the light rays to enter the pupil through the cornea. During this time the muscles in the iris control the size of the pupil making it smaller in bright light and larger in dark. Light rays then pass through the lens, which then passes through the retina. The retina contains cells called rods and cones. These cells then convert electrical impulses into images. It is stated that besides obvious obstructions like trees, buildings, clouds- the curvature of the earth is also one major factor that can reduce sightline. The earth curves at a rate of 8 in (20 cm) per mile, according to the department of chemistry. So, on a flat surface with our eyes five feet off the ground, the farthest we can see is about 3 mi (4.8 km) away.

It is important to consider that there are several conditions that create vision problems. Myopia can be caused by environmental or genetic factors. The common causes of myopia are working too closely on an object, or maximum time spent indoors. Nearsightedness or myopia can be corrected by a proper eye examination and using lenses or eyeglasses. These vision problems are estimated to affect more than 1.5 billion people worldwide.

With the eye alone, we can see hundreds or even thousands of stars. The farthest object mostly seen with the naked human eye is not a star but a galaxy of stars. Researchers experimented to determine how far we can see a candle flame from. They concluded that someone with a healthy vision can detect a candle flame from 1.6 mi (2.5 km) away, without any obstructions in the line of sight. If we note how far we can see, it really comes down to brightness around the object or in the surrounding. Therefore, distance and brightness have to coexist together for us to sight something at a distance.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for how do we see? Mind blowing kids facts on how your vision works! Then why not take a look at beetle life cycle: curious facts on insect development for kids! Or box turtle lifespan: curious reptile facts answered for kids!

The Kidadl Team is made up of people from different walks of life, from different families and backgrounds, each with unique experiences and nuggets of wisdom to share with you. From lino cutting to surfing to children’s mental health, their hobbies and interests range far and wide. They are passionate about turning your everyday moments into memories and bringing you inspiring ideas to have fun with your family.

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