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Visual Field Examinations

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Visual Field Examinations Powered By Docstoc
					 Week  3
 Visual Pathway and
  Visual field defects
 Monocular   retinal
  zone
 Nerve fiber/optic
  nerve zone
 Binocular chiasmal
  zone
 Post chiasmal zone
 Fielddefects are
 found opposite in the
 VF to the location of
 the damages in the
 eye.
RETINAL DETACHMENT   VISUAL FIELD
 Choroidal   lesions
  care caused by
  tumors,
  inflammations,
  infection, or fluid
  leaks.
 This type of damage
  does not respect the
  horizontal or vertical
  meridian.
EPI RETINAL MEMBRANE
TEAR WITH BLEEDING     HAMANGIOBLASTOMA
 Damage  may be
 caused by toxicity,
 inflammation,
 infections or heredity.
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.
 Damage to cone
 receptors causing
 damage to the central
 5 degrees.

 Decreased  color and
 VA will result.
 Retinal layer           All defects will be
 Subretinal layer         monocular.
 Rods and cones          Most pathology will be
 Retinitis pigmentosa     visible with a scope.
 Macular pathology       Lesions temporal to the
                           fovea will present nasal
                           on VF.
                          Lesions can cross all
                           meridians.
                          Central scotomas will
                           cause abnormal VA
                           and color vision.
 Nerve  fiber layer.
 Most common cause
  is glaucoma. Also
  may be caused by
  trauma, blood vessel
  occlusions, infections,
  inflammations and
  tumors
   (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.
 Macular and
 papillomacular
 defects create central
 or ceccocentral
 scotomas
 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.
 Nerve  fiber layer      All defects are
 Optic nerve              monocular.
  (papilledema)           Defect will point to
 Nerve fiber pattern      the disc since the
  defects                  nerve fibers are
 Bjerrum area defects     traveling toward this
                           point.
                          All pathology will be
                           visible with a scope
                       DAMAGE TO NERVE FIBER
GLAUCOMATOUS DEFECTS   LAYER WILL SHOW ON VF.
TEMPORAL WEDGE   NASAL STEP
OPTIC NERVE CENTRAL
SCOTOMA               VISUAL FIELD
 Allwill be monocular    Specific areas of
  only effecting the       nerve fibers that have
  damaged eye.             been damaged will
 Damage to the nerve      respect the horizontal
  fiber layer will be      meridian and point in
  caused by glaucoma.      the direction of the
 The VF will show up      disc.
  opposite of the         Disc problems will
  damaged area.            be visible with a
                           scope.
   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.
LATERAL GENICULATE
BODY                 OPTIC RADIATIONS
 Homonymous   defect     Not visible with a
  will always be           scope.
  present. (Same side)    Problem will be
 Will start out small     visible with CT or
  and gradually get        MRI scan.
  larger.
 Will be hemianopic
  and will respect the
  vertical meridian.
 Followthe pathway-
 Page 22 in your text.




 What   is this problem?
See you next week for Goldmann Perimetry lecture.

				
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