structure of the eye

• Eye structure


  • Cross section of the eye
  • Light hits the cornea
  • Iris controls pupil size
  • Lens refracts light
  • Retina has cone and rod cells
  • Fovea has only cone cells
  • Optic nerve transmits impulses to brain
• Iris reflex


  1. Pupil constricts in bright light

  2. Pupil dilates in low light

  3. Circular muscles contract to constrict pupil

  4. Radial muscles contract to dilate pupil
• Bright light conditions


  Pupil constricts to prevent retina damage
• Low light conditions


  Pupil dilates to allow more light in
• Cone cells are sensitive to color, rod cells allow black and white vision in low light
• Fovea is a region of the retina with only cone cells, used for clearest vision
• Optic nerve transmits impulses from receptor cells in the retina to the brain