The Eye

Question 1

What is the role of the cornea and the lens?

Answer 1

Light enters the eye through the pupil. The cornea and lens focus the light to form a sharp image on the retina

Question 2

Describe what the retina does

Answer 2

The retina contains receptor cells called cones and rods that detect light and form an image. The nerves in the retina convert the image to electrical signals that are sent to the brain along the optic nerve

Question 3

Describe what cataracts is and how it can be treated

Answer 3

Cataracts occurs when the lens becomes cloudy, so light can not pass through properly (blurred vision).
It can be treated by replacing the cloudy lens with an artificial lens

Question 4

Describe what causes colour blindness

Answer 4

A normal retina contains 3 types of cone that detect red, green and blue light. The colour of an image is detected by how much each cone is stimulated. Colour blindness occurs when at least one cone is missing/doesn’t work properly

Question 5

How can long sightedness be corrected?

Answer 5

By using a converging lens (brings the rays together, so light is focused on the retina)

Question 6

How can short sightedness be corrected?

Answer 6

By using a diverging lens