3.1.5 eye function

• accommodation

  • lens in eye changing shape to focus on an object as its distance from the eye changes
  • done by the ciliary muscles and the suspensory ligaments
• colour blindness

  • inherited condition
  • caused by defects in the photoreceptors in the retina
  • rods and cones are photoreceptors
• Object that is close

  • concentration of ciliary muscles
  • relaxed suspensory ligaments
  • lens becomes thicker + rounder, resulting in significant refraction of light rays
• Object that is far

  • relaxed ciliary muscles
  • concentration/tightening of suspensory ligaments
  • lens becomes flatter + thinner, results in minor refraction of light rays
• Too much light exposure

  • iris decreases pupil size
  • let less light in
• Too little light exposure

  • iris increases pupil size
  • let more light in
• Myopia

  • short-sightedness
  • happens when the light focuses in front of the retina
• Hyperopia

  • long-sightedness
  • happens when the light focuses behind the retina