The eye

• Label these structures in the eye

  A) Conjunctiva

  B) Ciliary body

  C) Suspensory ligaments

  D) Pupil

  E) Cornea

  F) iris

  
• Label these structures in the eye

  A) Scelera

  B) Retina

  C) Fovea

  D) Blind spot

  E) Optic nerve

  F) Choroid

  G) Lens

  
• What is the visual defect in the image?

  Myopia

  
• What is the visual defect in the image?

  Hypermetropia

  
• What visual defect is when you can see close up but not far?

  Myopia
• What visual defect is when you can see far away but not close up?

  Hypermetropia
• Hypermetropia:

  • when you can see far away BUT not close up
  • eye is too short
  • the cornea of lens is too flat
  • light rays meet behind the retina
  • SOULTION: wear convex lenses

  
• Astigmatism

  • Causes: hereditary but can be caused by injury irregularly shapes lens or cornea
  • Treatment: Corrective lenses
• Cataracts:

  • Cause: old age where proteins in the eye clump together results in clouding of the lens where less light enters the eye
  • Treatment: surgery to remove hardened cloudy layer above lens
• Pupillary mechanism

  A) Circular muscles

  B) Radial muscles

  
• Dim light:

  • Radial muscles contract
  • Circular muscles relax
  • Pupils dilate
  • More light let into the eye
• Bright light:

  • Radial muscles relax
  • Curcular muscles contract
  • Pupil reduces
  • Less light let into the eye
• Near vision >6m:

  • ciliary muscle contracts
  • suspensory ligaments slacken
  • lens becomes more convex (bulges)
  • refraction increases
  • clear image formed on retina
• Distant vision >+6m:

  • Ciliary muscle relaxes
  • suspensory ligaments pull taught
  • lens becomes flatter
  • refraction decreases
  • clear image formed on retina
• The function of the conjunctiva is to protect
• The functions of the sclera is to protect and maintain shape of eye.
• The sclera is the white, fibrous layer of the eye.
• The receptors in the eye are the rods and cones.
• Rods are for black and white vision.
• Which area of the retina produces the highest focus?

  Fovea (yellow spot)
• Area of the retina where there are no rods or cones.

  Blind spot
• The blind spot is created due to where the optic nerve leaves the eye.
• The choroid is the layer of the eye filled with blood vessels.
• The function of the choroid is to?

  Provide nutrients to the eye and absorb excessive light.
• What TWO characteristics about the lens allows it to do its function?

  1. Flexible
  2. transparent
• The function of the lens it to:

  refract and focus light into the retina
• Which structure of the eye is responsible for how much light enters the eye?

  Iris
• The iris contain radial and circular muscles.
• The iris is responsible for the pupillary mechanism.
• The cornea covers only the front area of the eye.
• The cornea is the site of highest light refraction
• The cornea contains pain receptors.
• The suspensory ligaments are attached to the lens
• What is the function of the suspensory ligaments?


  Controls the thickness of the lens.
• What causes astigamatism

  1. Inherited
  2. injury
• How do we treat astigmatism?

  corrective lenses
• What causes cataracts?

  Protein build up which causes clouding in the lens.