When you step into bright light, for example, the eyelids squeeze together tightly to protect your eyes until they can adjust to the light. And if you flutter your fingers close but not too close!
Our vision allows us to be aware of our surroundings. Eighty per cent of everything we learn is through our sight. Your eye works in a similar way to a camera. It's all about light. Light reflects off an object, and if that object is in your field of vision, it enters the eye. The first thing it touches is a thin veil of.
Your friend's eyelids shut automatically to protect the eye from possible danger. And speaking of fluttering, don't forget eyelashes. They work with the eyelids to keep dirt and other unwanted stuff out of your eyes.
Doctors use special microscopes to look at these inner parts of the eye, such as the lens. The eyes you have will be yours forever — treat them right and they'll never be out of sight! It holds millions of cells that are sensitive to light. The lens also bends light, increasing the amount focused on the highly specialised cells of the retina. After ageing, smoking is the biggest risk factor for developing AMD and also increases your risk of developing cataracts.
The sclera is made of a tough material and has the important job of covering most of the eyeball. Think of the sclera as your eyeball's outer coat. Look very closely at the white of the eye, and you'll see lines that look like tiny pink threads. These are blood vessels, the tiny tubes that deliver blood, to the sclera.
The cornea say: KOR-nee-uh , a transparent dome, sits in front of the colored part of the eye. The cornea helps the eye focus as light makes its way through. It is a very important part of the eye, but you can hardly see it because it's made of clear tissue.
Like clear glass, the cornea gives your eye a clear window to view the world through. Behind the cornea are the iris, the pupil, and the anterior chamber. The iris say: EYE-riss is the colorful part of the eye. When we say a person has blue eyes, we really mean the person has blue irises! The iris has muscles attached to it that change its shape.
This allows the iris to control how much light goes through the pupil say: PYOO-pul. The pupil is the black circle in the center of the iris, which is really an opening in the iris, and it lets light enter the eye. To see how this works, use a small flashlight to see how your eyes or a friend's eyes respond to changes in brightness. The pupils will get smaller when the light shines near them and they'll open wider when the light is gone.
The anterior say: AN-teer-ee-ur chamber is the space between the cornea and the iris. This space is filled with a special transparent fluid that nourishes the eye and keeps it healthy. These next parts are really cool, but you can't see them with just your own eyes!
Doctors use special microscopes to look at these inner parts of the eye, such as the lens. After light enters the pupil, it hits the lens. The lens sits behind the iris and is clear and colorless. The lens' job is to focus light rays on the back of the eyeball — a part called the retina say: RET-i-nuh. The lens works much like the lens of a movie projector at the movies. Next time you sit in the dark theater, look behind you at the stream of light coming from the projection booth. This light goes through a powerful lens, which is focusing the images onto the screen, so you can see the movie clearly.
In the eye's case, however, the film screen is your retina.
Your retina is in the very back of the eye. It holds millions of cells that are sensitive to light.
The retina takes the light the eye receives and changes it into nerve signals so the brain can understand what the eye is seeing. The lens is suspended in the eye by a bunch of fibers. These fibers are attached to a muscle called the ciliary say: SIL-ee-air-ee body. It has the amazing job of changing the shape of the lens. That's right — the lens actually changes shape right inside your eye! Try looking away from your computer and focusing on something way across the room.
Even though you didn't feel a thing, the shape of your lenses changed. When you look at things up close, the lens becomes thicker to focus the correct image onto the retina. When you look at things far away, the lens becomes thinner. The biggest part of the eye sits behind the lens and is called the vitreous say: VIH-tree-us body.
The vitreous body forms two thirds of the eye's volume and gives the eye its shape. It's filled with a clear, jelly-like material called the vitreous humor. Ever touch toy eyeballs in a store?
Sometimes they're kind of squishy — that's because they're made to feel like they're filled with vitreous humor. In a real eye, after light passes through the lens, it shines straight through the vitreous humor to the back of the eye. The retina uses special cells called rods and cones to process light. Just how many rods and cones does your retina have? How about million rods and 7 million cones — in each eye!
An example of the two systems in operation can be seen when you walk down the street. The orientation system allows you to easily move in and out of the path of other people, and stops you from falling over or walking into a lamppost. But when your eye catches sight of something interesting in a shop window, you switch over to the discover system to get the full picture.
We use these two systems alternatively without even realising it.
Since the orientation system requires less energy, we quickly switch back to it when we have enough information. In reality, we know that objects with certain characteristics are better at catching our attention, while others are better at holding our attention. My research shows that we are more likely to notice certain products, which use these basic design parameters to stand out. To keep our attention the brain needs to decide that it is worth using energy to understand this new object. And research shows that we keep our attention on things that are easier to understand.
If it becomes too demanding, or nothing else is happening, our attention slips, and we begin to look at something else. Is it worth the effort to continue? In visiting this site, you already made up your mind that you would find something interesting to read. Also of significance is the amount of information you receive.
Research shows that the number of elements that we can see directly influences whether we continue to look or shift our gaze elsewhere. When there are too many things to look at, the brain needs to work harder, and there is a higher risk that we will stop paying attention. Our brain is simply not good at multitasking. It is quite impressive that a brain designed for a life thousands of years ago copes as well as it does in the modern world.
This is due to our ability to adapt. In fact, it takes the brain less than a minute to adapt to new surroundings. You can try this yourself: Try looking at this image above of a moving spiral for 30 seconds, and then look away. But then see just how quickly your brain switches back to a world where those objects are once again stationary. When I research the workings of the eye and the brain at Copenhagen Business School CBS , which you might not associate with this type of research, it is because it helps us to understand how we as consumers make choices.
And studying the visual system, gives valuable insights into why consumers sometimes make irrational choices. Over many years of research at CBS, I have conducted experiments and tests to find out what captures and holds our attention. My research ranges from questions of what we perceive as being ugly or pretty, to what prompts us to sometimes buy a cat in a hat.
Read this article in Danish at ForskerZonen, part of Videnskab. The eyes look, but the brain sees May 6, -