How the eye works

How Does the Eye Work?

Approximately 80 percent of everything we learn comes through our eyes — the question is, how?

The eye contains over two million working parts and is considered the second most complex organ in the body— the most complex is the brain.

The inner structures of the eye all work together to produce an image that your brain can understand.

In this article we will see how the eye works

In order to produce a clear image, the eyes must complete a five step process:

Step 1: Light enters the eye through the cornea

When we look at an object, the light that is reflected off of the object enters the eye through the clear front layer of the eye, called the cornea. The cornea bends the light before it passes through a watery substance that fills the area behind the cornea, called the aqueous humor.

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ConjunctivitisStep 2: The pupil adjusts in response to the light

The light continues to travel through the black opening in the center of the iris, called the pupil. The iris is the colorful part of your eye that gives it its blue, green, hazel, brown or dark appearance.

The pupil then automatically gets bigger or smaller, depending on the intensity of the light.

How does the pupil expand and contract?

The iris is actually made up of muscles that expand and contract to control the pupil and adjust its size. So when you see your pupil getting bigger or smaller, it is really the iris that is controlling the pupil opening in response to the intensity of light entering the eye.

Step 3: The lens focuses the light onto the retina

The light passes through the pupil to the lens behind it. The lens adjusts its shape to bend and focus the light a second time, to ensure that you have a clear image of what you are looking at.

At this point, the light has been bent twice— as it moved from the cornea through the lens, and then from the lens to the retina. This "double bending" has actually flipped the image upside down.

Step 4: The light is focused onto the retina

The light then passes from the lens to the back of the eye which is filled with a clear, gelatinous substance called the vitreous until it reaches the retina, the light-sensitive layer at the back of the eye.

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Hi, My name is bharti and I am a technical expert at Bharti Eye Foundation