Visual Field Examinations

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Visual Field Examinations

• Week 3
• Visual Pathway and Visual field defects

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4 major visual pathway zones

• Monocular retinal zone
• Nerve fiber/optic nerve zone
• Binocular chiasmal zone
• Post chiasmal zone

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Monocular retinal zone
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Retinal layer

• Field defects are found opposite in the VF to the
  location of the damages in the eye.

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Retinal layer

• Retinal detachment

• Visual field

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Sub retinal layer

• Choroidal lesions care caused by tumors,
  inflammations, infection, or fluid leaks.
• This type of damage does not respect the
  horizontal or vertical meridian.

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Sub retinal layer

• Epi retinal membrane tear with bleeding

• hamangioblastoma

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Rods and cones

• Damage may be caused by toxicity, inflammation,
  infections or heredity.

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Retinitis pigmentosa

• A diffuse pattern of field loss ( rod damage)
  forming a ring a variable scotomas that will
  expand outward toward the periphery and inward
  toward the fovea until blindness results.

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Macular pathology

• Damage to cone receptors causing damage to the
  central 5 degrees.
• Decreased color and VA will result.

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Monocular retinal zoneCharacteristics

• Retinal layer
• Subretinal layer
• Rods and cones
• Retinitis pigmentosa
• Macular pathology

• All defects will be monocular.
• Most pathology will be visible with a scope.
• Lesions temporal to the fovea will present nasal
  on VF.
• Lesions can cross all meridians.
• Central scotomas will cause abnormal VA and color
  vision.

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Nerve fiber layer/optic nerve region zones

• Nerve fiber layer.
• Most common cause is glaucoma. Also may be caused
  by trauma, blood vessel occlusions, infections,
  inflammations and tumors

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Papilledema

• (swelling of the disc)
• Produces a field loss by pushing the surrounding
  retina out from the disc creating an enlarged
  blind spot.
• It will present more concentric than an enlarged
  blind spot caused by glaucoma.

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Nerve fiber defect patterns

• Macular and papillomacular defects create central
  or ceccocentral scotomas

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Bjerrum Defects

• Bjerrum area of nerve fiber layer.
• 15 degrees off fixation.
• Defect in this area will cause an arcing VF loss
  opposite of the damage.
• Will start small and increase in size over time.

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Nerve fiber layer/optic nerve region
characteristics

• Nerve fiber layer
• Optic nerve (papilledema)
• Nerve fiber pattern defects
• Bjerrum area defects

• All defects are monocular.
• Defect will point to the disc since the nerve
  fibers are traveling toward this point.
• All pathology will be visible with a scope

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Nerve fiber/optic nerve region

• Glaucomatous defects

• Damage to nerve fiber layer will show on VF.

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Glaucoma

• Temporal wedge

• Nasal step

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Nerve fiber/optic nerve region

• Optic nerve central scotoma

• Visual field

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Optic nerve zone
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Nerve fiber/ optic nerve region Characteristics

• All will be monocular only effecting the damaged
  eye.
• Damage to the nerve fiber layer will be caused by
  glaucoma.
• The VF will show up opposite of the damaged area.

• Specific areas of nerve fibers that have been
  damaged will respect the horizontal meridian and
  point in the direction of the disc.
• Disc problems will be visible with a scope.

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Binocular Chiasmal Zone
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Binocular chiasmal zone

• Bi temporal VF loss characteristics

• Caused by pituitary tumors or swelling,
• Always bi temporal.
• Not visible with a scope.
• CT scan or MRI needed to show defect.
• Bilateral hemianopia (temporal).
• Will respect vertical meridian.
• Will start small and gradually increase in size.

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Post chiasmal zone
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Post chiasmal zone

• Lateral geniculate body

• Optic Radiations

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Post chiasmal zone

• Not visible with a scope.
• Problem will be visible with CT or MRI scan.

• Homonymous defect will always be present. (Same
  side)
• Will start out small and gradually get larger.
• Will be hemianopic and will respect the vertical
  meridian.

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Lets see what you learned!

• Follow the pathway-
• Page 22 in your text.
• What is this problem?

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What is the problem here?
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Whats the problem here?
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Last two, whats wrong?
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Great job!

• See you next week for Goldmann Perimetry lecture.