THE SENSE OF SIGHT

THE EYES AND THE BRAIN

The retina captures light from an object. This information is sent to the brain through the optic nerve.
The brain interprets the information.

1. The girl's eyes see a flying object.
2. This information is sent to her brain through the optic nerve.
3. Her brain knows that it is a bird and not a butterfly.

THE EYES

The eyes are the sense organs of sight. Their function is to capture light.
Eyes are very delicate and need protection.

• Eyelids protect the eyes by opening and closing.
• Eyebrows and eyelashes protect the eyes from dirt.
• Tears keep the eyes moist.

There are five main parts: the cornea, the pupil, the iris, the lens and the retina.

• First, light passes through the cornea. The cornea is transparent.
• Then, light passes through the pupil. The pupil is the hole in the centre of the iris.
• The level of light is controlled by the iris. The iris is a coloured ring.
• The lens helps the eye to focus.
• Finally, the retina captures the light.

THE SENSE OF SIGHT

The sense of sight is used to distinguish shapes, colours, size and distance.
To see:

• There must be light.
• The light must reach your eyes.