The Human Eye

The eye is an organ made of over 2 million parts that work together to process light and help us interpret shapes, colours and dimensions around us. This guide will take you through the fascinating visual process - which, like a camera, begins when light is captured at the front of the eye, travels through the middle and ends at the back of the eye.

How light enters the eye

Everything around us is made of surfaces that reflect light in varying wavelengths. These light rays enter through the cornea at the front of the eye and pass freely through the pupil.

Move the brightness slider to explore how the eye filters light.

Brightness

Lens adjusts focus

Next, the light makes its way through the crystalline lens, which bends the rays and flips them back onto the retina, resulting in a reverted image.

Move the focus slider to discover how images focus on the retina.

Focus

Brain interprets the image

Finally, the light rays go through a sharp focusing point of the retina, where they are transformed into electrical signals that reach our brain via the optic nerve. The brain then flips the images again, so we don’t see the world upside down.

Anatomy of the eye

Click on the plus buttons to learn about the functionality of the optic nerve, pupil, conjunctiva and other parts of the eye.

Cornea

The clear, dome-shaped front part of the eye that helps your eye focus light, so you can see clearly.

Pupil

The opening in the centre of the iris that controls the amount of light passing through to the back of the eye.

Crystalline Lens

The transparent, elastic structure inside the eye that bends to focus light rays onto the retina.

Aqueous Humour

The clear, watery fluid in the front of the eyeball made up of water, sugars and various nutrients. It nourishes the cornea and the lens and gives the eye its shape.

Iris

The coloured part of the eye surrounding the pupil that controls the amount of light that enters into the eye.

Conjunctiva

A clear, thin transparent layer of tissue that covers part of the front surface of the eye and the inner surface of the eyelids.

Sclera

The dense protective tissue of the eyeball that forms the ‘white’ of your eye. Sclera forms over 80% of the surface area of the eyeball, from the cornea to the optic nerve.

Vitreous Humour

A clear gel-like substance that occupies the space between the crystalline lens and the retina and transmits initial light waves.

Optic Disc (Blind Spot)

A disc on the retina that is the point of entry of the optic nerve. It lacks visual receptors, so it’s also known as the blind spot.

Macula

The central part of the retina that allows us to see fine details.

Fovea

The central part of the macula, necessary for activities where visual detail is important, such as driving or reading.

Retina

The light-sensitive nerve layer that lines the inside of the back of the eye. It creates electrical signals that travel through the optic nerve to the brain.

Optic nerve

A bundle of nerve fibres that connect the retina with the brain and help us interpret what we see.

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Nerve signals Light rays
Pupil
Iris
Cornea
Sclera
Conjunctiva
Crystalline Lens
Aqueous Humour
Retina
Macula
Fovea
Optic Disc (blind spot)
Optic nerve
Vitreous Humour