The eye and visual tests

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The eye and visual tests

• Exercises 31 and 32

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Links

• http//getbodysmart.com/ap/nervoussystem/sensory/s
  ensation.html
• http//www.eschoolonline.com/company/examples/eye/
  eyedissect.html

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Procedure A-structure and function of eye

• locate on the models
• Eyelid (palpebrae)
• Conjunctiva
• Orbicularis oculi
• Levator palpebrae superioris
• Lacrimal apparatus (lacrimal gland, superior and
  inferior canaliculi, lacrimal sac, nasolacrimal
  duct)
• Extrinsic eye muscles (superior rectus, inferior
  rectus, medial rectus, lateral rectus, superior
  oblique, inferior oblique)

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More parts to know

• Outer fibrous layer-find sclera (white of eye)
  and cornea (window of eye)
• Middle vascular layer-find choroid coat, ciliary
  body, iris (colored portion), pupil (opening in
  iris)
• Inner nervous layer-find retina (macula
  lutea-yellow spot, fovea centralis-sharpest
  vision, optic disc (blind spot). Also find optic
  nerve
• Lens
• Anterior cavity-anterior chamber, posterior
  chamber, and aqueous humor (produced
  continuously)
• Posterior cavity-vitreous humor (present at
  birth, not replaced)

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Procedure B eye dissection

• AT least one person on the table should dissect a
  sheep eye, and all others at table should
  observe.
• Find as many of the parts from the model and
  figures as you can
• Be careful! http//www.jburroughs.org/science/reso
  urces/skeleton/eye/eyedissection.html
• http//www.bio.psu.edu/people/faculty/strauss/anat
  omy/nerv/dissectedeye.htm

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Exercise 32 Visual tests

• Procedure A-use the Snellen eye chart provided
  for visual acuity test
• Use the astigmatism chart provided to test your
  eyes for astigmatism (the cornea is shaped
  imperfectly
• accommodation test-follow directions for this
  test
• Color vision test-use the plates on your lab
  manual and/or the color test kits

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Procedure B

• Blind spot demonstration-use figure or the slips
  of paper provided
• Photopupillary reflex-follow directions
• Accommodation pupillary reflex-follow directions
• Convergence reflex-follow directions

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Accommodation of lens
Far vision
Near vision