the eye

• ciliary muscles and suspensory ligament 


  both control the shape of the lens
• pupil


  gap to allow light in
• iris


  muscle that controls pupil size
• lens 


  refracts light
• retina


  thousands of receptor cells to deflect light
• optic nerve


  bundle of neurones connected to the brain
• cornea and conjunctiva


  protects the the eye
• myopia


  can't see distant objects- concave lens

  1. ciliary muscle relaxes
  2. suspensory ligament is tight
  3. lens become narrow
  4. light refracts less
  5. light focuses on the retina
• hyperopia


  can't see near objects- convex lens

  1. ciliary muscle contracts
  2. suspensory ligament is loose
  3. lens becomes wide
  4. light refracts more
  5. light focuses on the retina
• bright light

  1. radial muscle relaxes
  2. circular muscle contracts
  3. pupil constricts
  4. less light enters
• dim light

  1. radial muscles contracts
  2. circular muscles relaxes
  3. pupil dilates
  4. more light enters