My Science School

The human eye is a ball containing a kind of jelly that keeps it round, just as the air in a balloon keeps that round. At the front is a lens, through which light can enter the eye. The lens can change shape to focus light from different distances. Like a slide projector, the lens throws an image onto the back of the eye, which is called the retina. In fact, the image is upside down, but your brain, which makes sense of everything you see, sorts out the image so that you “see” it the right way up.

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. When you look at an object, light reflected from the object enters the eyes through the pupil and is focused through the optical components within the eye.

The front of the eye is made of the cornea, iris, pupil and lens, and focuses the image onto the retina. The retina is the light sensitive membrane that covers the back of the eye. This membrane consists of millions of nerve cells which gather together behind the eye to form a large nerve called the optic nerve.

When the light enters the eye, it is focused to a pinpoint on the macula, a small area in the centre of the retina at the back of the eye. The macula is responsible for central detailed vision, allowing you to see fine detail and colour, read and recognise faces.

When light stimulates the nerve cells in the retina, messages are sent along the optic nerve to the brain. The optic nerves from the two eyes join inside the brain. The brain uses information from each optic nerve to combine the vision from the two eyes allowing you to see one image.