Have you ever wondered how your eyes work? We wanted to share this short video from National Eye Institute explaining how your visual system works. Share with your kids for a quick, informative science lesson!
Your eyes allow you to see the world around you, but have you ever wondered how they work? First, it’s important to know that vision depends on your brain as much as on your eyes. Your eye’s main job is to detect patterns of light. Then, they’ve work with your brain to turn those patterns into images. Let’s take a closer look. Light rays bounce off an object you are looking at, let’s say the object is a dog. The light reflects off the dog to your eye. Then, the light enters through the outer part of your eye called the cornea. The cornea is clear like a window. It helps your eye focus the light to make things look sharp and clear. Next, the light rays pass through an opening called the pupil. The pupil is the dark round circle in the colored part of your eye. The colored part is called the iris. It controls how wide the pupil is and how much light can pass into your eye. In bright light, the iris narrows the pupil, reducing the amount of light that enters the eye. In dim light, the iris widens the pupil to let in more light. All of this happens automatically. Behind the iris is the lens of the eye. It helps focus the light coming into your eye so you can see things clearly. The lens flattens so you can see things that are far away and bends so you can see things up close. When the lens, cornea, and pupil are all working together properly, they will focus light on the back of the eye. That’s important because lining in the back of the eye is the retina. There are about a hundred and thirty million tiny cells in the retina that are sensitive to light. When these cells detect light, they turn it into electrical signals. Those signals eventually make their way through the optic nerve, which is like a cable connecting the retina to the brain. The retina helps create a rough image but it sees the world upside down. It’s your brain that turns what you see right-side up. Also when you look at an object each eye gets a slightly different view of the world. The brain combines those views and makes them into one picture. The brain also adds a lot of details to your vision so that you can see complex shapes, movement, depth, and a rainbow of colors. And, of course, the brain connects your sense of sight to things you already know, so that when you see a dog you recognize it as a dog, and not a cat, or a monkey. And that’s how you’re able to see.
To learn more about how your eyes work, visit NEI.NIH.gov/kids.