VFD Lecture Part 3

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VFD Lecture Part 3
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Damato Campimeter

• More precise, accurate
• and reliable test with
• better examiner control
• Portable
• Only measures central
• visual field

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Component Parts of the Campimeter
A test card B Side arm C Eye cover D Test
Grid E Stimulus window F Target stimulus G
Target arm and finger notches on the
arm and card
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Test Procedure

• Test materials
• Damato Campimeter
• Test form
• Book stand (optional)
• Eye patch or clip on occluder (optional)
• Environment
• Well lighted room light behind the patient and
  evenly illuminating the board
• Room must be free from distractions

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Test Instructions

• Patient seated comfortably at a table with
  eyeglasses on if needed to see board
• Instruct patient to hold the board upright on the
  table top unless a book stand is being used
• EX is positioned in front of the patient so that
  the patients eyes can be observed
• Instruct the patient to cover the eye using the
  eye cover folded inward (an eye patch can be used
  instead)
• Make sure there are no shadows on the board and
  that the patients head is centered (not tilted
  sideways)

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Correct examination position
Avoid tilting the head or the card
when administering the test
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• Adjust the card so it faces the client squarely,
  with the
• board 13 inches from the eye
• Tilt the care backward and forward until the
  client feels
• comfortable
• Make sure the window is blank
• Instruct patient to focus on the window and to
  say now
• when the black dot appears
• Show the dot in the window repeat several
  times until
• patient responds every time the dot is shown

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• PROCEED WITH TEST
• Show the patient the number 1 on the grid
• Instruct the patient to keep looking at the
  number 1 and to
• say Now when the black dot appears
• Watching the patients eye closely, move the dot
  into the
• window. Avoid giving any clues (noise or sudden
  movement
• of the hand
• If there is any doubt about the validity of the
  patients response,
• immediately retest that point before proceeding
  onto the next point
• Record the patients response on the form
• Return the window to a blank frame and instruct
  the patient to
• read the next number out loud
• Repeat until the patient has viewed all of the
  numbers

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Modifications for Non Compliant Patients

• The number can be highlighted to help maintain
  the patients attention/fixation
• The number of test items can be reduced from 30
  to 15 for patients with limited attention and
  endurance
• The patient can raise a finger or point to the
  target instead of giving a verbal response
• The test can be broken down into short segments
  and given over several days

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Scoring
If the patient does not see the black dot at the
test location, place a black mark at that
location on the test form When the test is
completed, connect the dots to indicate the area
of field loss NOTE the test form is held
one direction for scoring and the opposite
direction for interpretation
Results indicate a left Homonymous hemianopsia
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Additional Assessments
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Oculomotor Changes

• Can be used to help confirm other observations
• Patient is asked to gaze shift between targets
• Patient often demonstrates searching saccade
  towards a target on the blind side
• Makes several saccades toward the target instead
  of one smooth saccade
• But makes a normal long smooth saccade towards
  the intact side

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Insight into Visual Field Loss

• Patient must have good insight in order to apply
  compensatory strategies
• Patient often misunderstands diagnosis
• Believes the deficit is in one eye only
• Believes the deficit only affects peripheral
  field
• Believes the deficit is in the eye not the brain
• Patient is unable to describe strategies used to
  compensate for loss

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Insight Can be Measured With a Simple Scale

• 5 Demonstrates thorough understanding of
• VFD understands that deficit is in both eyes
  and knows which side has been affected can
  describe how deficit has affected functional
  performance and safety able to verbalize
  strategy needed to compensate and consistently
  employs strategy
• 4 Demonstrates understanding of VFD, understands
  that deficit is in both eyes and knows which side
  has been affected by deficit can describe how
  deficit affects function and safety able to
  verbalize strategy needed to compensate but does
  not consistently employ strategy

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Insight rating

• 3 demonstrates understanding of cause of VFD and
  which side has been affected by deficit
  minimizes affect of deficit on functional
  performance and safety and/or does not fully
  understand how deficit affects function and
  safety able to verbalize strategy needed to
  compensate but does not employ strategy
• 2 realizes deficit is present knows which side
  is affected may not realize deficit is in both
  eyes not able to verbalize a compensatory
  strategy and/or cannot describe how deficit
  affects function and safety
• 1 may be aware that vision has changed but is
  unaware of the visual field deficit

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Assessment of Influence of VFD on Visual Search

• Observational assessment
• Questions to be answered
• Does the VFD disrupt visual search?
• How is the search pattern disrupted?
• Does the patient initiate a compensatory
  strategy?
• Assess two areas
• Search in central visual field
• Search in peripheral visual field

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Visual Search Capability in the Central Visual
Field

• Observe performance on cancellation tasks
• Visual search subtests of Brain Injury Visual
  Assessment Battery for Adults (biVABA)

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Normal Visual Search

• Persons without visual impairment demonstrate
  specific characteristics of search patterns that
  make them effective in locating and identifying
  targets
• Linear strategy
• Left to right and top to bottom
• Symmetrical search pattern
• Predictable search pattern
• Thorough and comprehensive
• Resilient
• Consistent accuracy

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Four Normal Search Patterns

• All strategies are left
• to right and top to bottom
• Use of these strategies
• results in high degree
• of accuracy

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Characteristics of Ineffective Search Patterns

• Abbreviated and incomplete
• Asymmetrical
• Initiated and confined to right side
• Random-no predictable pattern
• Inconsistent accuracy in target identification
• Breaks down when challenged

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Evaluating Search Effectiveness

• Best evaluated by observing patient complete a
  search task
• Identify strengths and weaknesses of the search
  pattern
• Note accuracy
• Note time needed to complete search

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Observation of the Pattern

• __Symmetrical horizontal left to right
• __Symmetrical horizontal rectilinear
• __Symmetrical vertical left to right
• __Symmetrical vertical rectilinear
• __Checks work for accuracy
• __Abbreviated
• __ right side __ left side
• __Asymmetrical, right to left pattern
• __Random, no predictable pattern

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Cuing

• Should be part of the evaluation
• Physical
• Verbal
• Helps determine strengths and weaknesses
• A necessary component of treatment planning
• Example of documentation
• __ verbal cue given___benefits___no benefit
• __ physical cue give ___benefits___no benefit

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Ineffective Search Strategies Used by Persons
with VFD Abbreviated Search

• Abbreviates search towards blind side due to
  oculomotor disruption
• Results in omissions on the blind side
• Search pattern is organized
• Person checks work for errors
• Search is often time consuming
• Person maintains attention throughout test

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RVFD does not scan all the way over to the
right omissions on right side (black circles)
LVFD begins search a third of the way in from
the left side omissions on left side (black
circles)
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Visual Search Capability in the Peripheral Visual
Field

• Search of extrapersonal environment is often
  affected the most
• To compensate for VFD, the patient must initiate
  a quick, efficient search of the blind side
• Assessment determines whether patient
  demonstrates the essential components of a
  successful compensatory search strategy

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Dynavision 2000
Computer driven light board displays random
pattern of interactive lights Person locates the
light and touches it Light beeps when it is
touched to verify contact and immediately a new
light appears in another area of the board 30,
60 sec or 4 minute run is completed Two Modes
Mode A Light stays on until it is touched Mode
B Light stays on for a pre-determined length
of time and then changes
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Computer Analyzes Reaction Time in Each Quadrant
on Completion of a Run
Example of Print Out Analysis for Mode A Run
Completed on a Patient with a RVFD
Patient hit 28 lights during the 60 second
run The reaction times for the Left
quadrants(13) are 1.7 and 1.2 seconds The
reaction times for the right quadrants (24) are
2.2 and 2.9 seconds, confirming slower reaction
time towards VFD side
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Flash Option Mode
1-7 numeric digits appear in the box every 6 sec
during the run or Mode A or B The patient must
read out the digit(s) while continuing to hit the
lights Enables evaluation of persons ability
and willingness to shift attention between the
central and peripheral areas of the board
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Dynavision Performance
Deficient Performance
Good Performance

• Searches good field first
• Does not turn head or
• doesnt turn head far
• enough towards blind side
• Uses a time consuming
• strategy (often linear)
• Focuses attention on one
• side of the board

• Looks to blind field first
• Turns head to view periphery
• of board
• Uses an efficient circular
• search strategy
• Attends equally to both sides
• of the board

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If you dont have a Dynavision

• Get one
• At 7,000 falls into the expensive range making
  it difficult to get one through standard budget
  procedures
• Look instead for a donor
• Hospital auxiliary
• Foundation supporting the hospital
• Sorority or service club
• Not that difficult as it represents a one time
  purchase of a unique piece of equipment that is
  plaque-able ( you can put a nice bronze
  donation plaque on it)
• Cheap mans dynavision
• Laser pointer-aim it at a white wall and have
  patient locate the red dot

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Scan Course

• Assesses integration of visual search with
  ambulation
• Observe whether patient is willing to scan the
  environment during ambulation or uses the
  maladaptive strategy of fixating on the floor or
  staring straight ahead
• Can be set up anywhere
• Home or clinic

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Scan Course
Use 3x5 inch note cards with black 1 inch stick
on letters or post it notes with letters written
on them in magic marker. Place in various
locations along a hallway, 10 on each
side Instruct patient to read out the letters
as h/she walks down the hallway Record the
number of errors made on each side of the
hallway. Provide feedback on error rate and have
the patient repeat,walking the opposite
direction
Yellow post it notes with letters on them are
arranged along a hallway in a pts home
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Scan Course Performance

• If the patient is unable to combine visual search
  with ambulation, h/she will miss letter targets
  on the blind side
• The patient should always be given feedback on
  performance and then asked to repeat the test
  going the opposite direction
• If performance improves on second attempt it
  indicates that the patient is able to benefit
  from feedback to improve compensation

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Supplement Evaluation with Observation of
Behavior in Dynamic Environments

• Hesitant, uncomfortable and anxious
• Uses trailing or attempts to follow you
• Comes very close to obstacles on blind side
• Uncertain in responding to subtle features
  (curbs, support surface changes)
• Stopping to search-unable to combine visual
  search with ambulation
• Appears or complains of disorientation