the eye

• what is accommodation?


  - when we look from a near to distant object and our eyes take time adjust

  - the light reaching the eye needs to be refocused onto the retina
• how do we see objects?

  - the light passes through the cornea and pupil

  - the lens refracts the light into the retina
• what’s the problem with accommodation of near objects?

  - light from a near object diverges it does not focus on the retina properly
• what does the eye do to accommodate near objects?

  - ciliary muscles contract which slackens the suspensory ligaments

  - the lens becomes thicker and refracts the light into a more focused point on the retina
• what is the problem of accommodation with distant objects?

  - light from a distant object over refracts it does not focus on the retina properly
• what does the eye do to accommodate distant objects?

  - the ciliary muscles relax which causes suspensory ligaments to pull tight

  - the lens becomes thin and refracts the light less, focusing it onto the retina
• what is myopia? 


  • also known as short sightedness
  • objects closer look clear while further objects are blurry
• what is hyperopia?


  • also known as long sightedness
  • further objects are clear while closer objects are blurry
• what are some treatments for the eye?

  • hard and soft contact lenses
  • laser surgery to change the shape of the cornea
  • replacement lens in the eye
• what can cause hyperopia?

  • the eyeball may be too short so the light is focused behind the retina
  • the lens becomes less elastic, lens is not able to become thick enough to focus on near objects
• how can we treat hyperopia?

  • using glasses with convex lenses
  • they partially focus the light before it enter the eye
• what can cause myopia?

  • they eyeball may be too long the light is focused at point in front of the retina
  • the lens may be too thick so it refracts and focuses the light in front of the retina
• how can we treat myopia?

  • using glasses with concave lenses
  • to partially unfocus the light before it enters the eye