The eye

• What is part labelled A?

  Ciliary muscle, controls thickness of lens

  
• What is part labelled B?

  Suspensory ligaments, controls thickness of lens

  
• What is part labelled C?

  Iris, controls size of pupil

  
• What is part labelled D?

  Pupil, controls amount of light entering the eye

  
• What is part labelled E?

  Cornea, protective

  
• What is part labelled F?

  Lens, controls size of pupils

  
• What is part labelled I?

  Retina, where light is focused

  
• What is part labelled K?

  Optic nerve, relays information to the CNS

  
• What is part labelled M?

  Sclera, protective white outer layer

  
• When focusing on a far object, the lens needs to be thinner so there is less refraction.
• When focusing on a close object, the lens needs to thicker so there is more refraction.
• What is myopia?

  • short sightedness
  • image is formed before the retina
  • because eye may be too long or lens too thick
  • so a concave lens is used to correct
• What is hyperopia?

  • long sightedness
  • image is formed behind the retina
  • because eye may be too short or lens too thin
  • so a convex lens is used to correct it
• Concave lenses will partially unfocus the light before it enters the eye.
• Convex lenses will partially focus the light before it enters the eye.
• Pupils constrict in a bright room to protect the eyes and take less light in. The pupils dilate in a dim room to take more light in and take in more information.