Eye

• Sclera


  The tough outer layer of the eye
• Cornea

  Transparent region of the sclera at the front of the eye that refracts light
• What controls the size of the pupil and regulates the light reaching the retina


  Iris
• The hole in the centre of the iris that allows light to pass through


  Pupil
• Suspensory ligaments

  Change the shape of the lens to focus light rays on the retina
• Near objects

  Ciliary muscles contract, suspensory ligaments relax and the lens become thicker and rounder
• Distant objects

  Ciliary muscles relax, suspensory ligaments tighten and lens becomes flatter
• The process of changing the shape of the lens to focus on near or distant objects


  Accommodation
• When the eye attempts to produce an image it falls behind the retina


  Hyperopia
• When the eye attempts to produce an image it falls short of the retina


  Myopia
• How can hyperopia be corrected

  Convex lenses
• How can myopia be corrected

  Concave lenses
• Risks of lens replacement 


  Retinal damage, cataracts, infections
• What is laser eye surgery

  It is used to fix visual defects in adults and to change the shape of the cornea
• Treatments for eye defects


  Contact lenses

  Laser eye surgery

  Replacement lens surgery
• Main functions of structures found within the eye

  Accommodation

  Adaptation to dim light
• Short sight may be caused by the eyeball being too long