2.87

Understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity

• Eye- Focuses light onto photo receptors
• Photo receptors- the sensory cells of the eyes known as the rods and cones
• When focussing on distant objects:
• The rays of light are almost parallel
• Lens remains flat and focussed on the retina (the inner area of the eye)
• The cilliary body relaxes
• When focussing on near objects:
• The lens has to adjust to the scattered light rays
• The cilliary body contracts which forces the Lens to become rounded
• This allows the image to be focussed on the retina