Steve Leslie B Optom FCOVD FACBO
6th International Congress of Behavioural Optometry 2010
Aetiology of visual field loss
Aetiology of visual field loss
 Ocular pathology: glaucoma, optic nerve,......
 Neurological conditions: MS,....
 Stroke
 Traumatic brain injury
 One study found bilateral visual field deficits in at least 1 in 7 of severe TBI patients*
*Groswasser
G
Z C h M Bl k t i E. Polytrauma
Z, Cohen M, Blankstein
E P l t
associated with traumatic brain i t d ith t
ti b i injury: incidence, nature and impact on rehabilitation outcome. Brain Inj 1990;4:161.
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Anatomy
 Field loss usually correlates well with visual pathway localised injury
 Unilateral optic nerve lesion
 Anterior chiasm
 Chiasm

Bitemporal
p
hemianopia
p and hemifield slide phenomenon
p
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Anatomy
 Optic tract
 Temporal lobe
 25% of postchiasmal
pathology
 Possible olfactory/gustatory hallucinations, seizures, aphasia (if dominant h i (if d i
side involved)
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Parietal lobe
 35% of postchiasmal lesions
 Field defects may be accompanied by agraphia, iipsilateral
il
l pursuit dysfunction
i d f
i
 If right parietal area lesion, consider possibility of left neglect
 Macula splitting more than sparing
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Occipital lobe
 80% infarct
 Macular sparing
 Often no other neurological company
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Effects on activities of daily living
 Reading: effects of right or left hemianopia
 Computer use
 Driving
 Balance issues
 Walking
 Television
 Interference with rehabilitation
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Effects on rehabilitation progress
Effects on rehabilitation progress and prognosis
 Visual field loss has been found to be negatively correlated with return to work in a follow up study over 15 years of Vietnam Veterans.
15 years of Vietnam Veterans
GroswasserZ, Cohen M, Blankstein E. Polytrauma associated with traumatic brain injury: incidence, nature and impact on rehabilitation outcome Brain Inj 1990;4:161
nature and impact on rehabilitation outcome. Brain Inj
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.
Severity of visual field loss (VFL)and health‐related
quality of
(VFL)and health
related quality of life
 “Health related quality of life is diminished even in persons with relatively minor VFL”*
 VFL causes difficulty with:
VFL diffi l i h
 Driving
 Dependency
 Mental health
 Distance vision  Peripheral vision
*McKean‐Cowdin R et al. Am J Ophthalmol 2007;143:1013‐1023. (Dohenyy Eye Institute LA)
y
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Visual field loss affects ADL’ss and and
Visual field loss affects ADL
rehabilitation progress
 Awareness of visual field loss may help patients to adjust behaviour and performance of ADL’s
 Other professionals may adjust therapies within the consideration of a visual field defect; communication is imperative.
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Assessment of visual fields
 History, history, history
 Bedside vs office assessment
 Objective testing  Behaviourally assessed functional fields
 Subjective fields
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Hierarchy of targets
Hierarchy of targets
in quadrants




Hand motion
Finger motion
Finger counting /matching
g
g/
g
Saccades to moving fingers/target (children, aphasia)
p
)
 Color brightness comparison
 Move single target across g
g
midlines, or present 4 red dots equidistant from central fixation (detects 78% of chiasmal defects)
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Marking field loss midlines
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Macula sparing (striate lesion)
Macula sparing (striate lesion)
vs splitting (3 ball technique)
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Amsler grid
 Uesful for subtle central and paracentral
scotomas which can often cause frustrating and difficult to diagnose g
symptoms of:
 Ghosting
 Blur
 “Double vision”
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 Tangent screen
 Static vs kinetic perimetry
i
 Computerized functional visual field assessment
 Computerised:REACT, C p
C ,
SDSST,SOSH, SEARCH, FASTREAD, INSPECT ICBO 2010
Focal and Ambient visual function
 Many severe traumatic brain injuries involve the midbrain, where peripheral retinal input is i
integrated with proprioceptive and vestibular d i h i
i d ib l information
 “the ambient visual process must let you know “th bi t i l t l t k
where you are in space and essentially where you are looking before you process information about what you are looking at” (Padula & Argyris)
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Ambient disruption
 Disruption of the ambient visual process disrupts the construct and stability of space so that the Z‐
axis loses reference.
i l
f
 The disruptions directly and indirectly cause:
 Spatial disorientation
ld
 Balance and postural difficulties
 Objects appear to move
 Floor tilting etc
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Impaired simultaneous processing
 Brain injury very frequently affects attention and simultaneous processing, making it difficult for people to:
 Visually attend and listen or talk as well
 Fixate a central perimeter target and detect and respond to a peripheral target, so perimetry is not always and accurate representation of visual field y
p
function/dysfunction
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O ti t h
b f t
Optic atrophy can be a factor  Raised intracranial pressure y
p
(head trauma, hydrocephalus, BIH))
 Papilloedema often undiscovered in acute care
 Anoxia (ICP, poor perfusion to optic nerve)
 Radiation optic neuropathy: focal or whole brain radiation:
 Posterior ischaemic optic neuropathy (PION) 1‐3 years post radiation
 Painless reduction in vision
 Can deteriorate rapidly with age due to combination of age and compromised neurons
 Possible anterior and/or posterior optic neuropathy
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Paracentral scotoma
 Frequently undiagnosed and symptoms attributed to refractive issues
 Often unhappy patients
 Commonly causes vague symptoms:
 Blurring
 Ghosting
 Doubling
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Quadrantanopia
 Commonly missed in assessment
 May cause unusual M l problems that nobody can explain eg
 Bumping into small objects
 Knocking over objects
 Severe reading problems
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Hemianopia
 Commonly associated with hemiplegia
 Commonly misunderstood by patients and family, they 




often think one eye’s vision is affected
often think one eye
s vision is affected
Orientation and mobility affected
Head turn?
Visual midline shift?
Insight/poor insight?
g p
g
Good/poor compensation?
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Riddoch phenomenon:
Static‐kinetic dissociation
 Person is aware of motion in a field “blind” to form 



detection
O i i l d Occipital and anterior visual pathway lesions
i i l h
l i
Due to separate functions of parvocellular (conscious, what) and magnocellular (unconscious, motion and (unconscious motion and location) streams
Humphrey (static) perimetry worse than Goldmann
(kinetic) result
Person often feels they can, and actually do, function better than the field defect suggests.
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Effects of visual field loss on
Effects of visual field loss on balance and movement
 Unsteady on feet or sitting:
 postural adjustments
 Difficulty walking straight
 Visual midline shifts, head and body turns
l dl
hf h d db d
 Confusion in busy environments
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Right homonymous hemianopia
 Missing/bumping into people or objects on the right
 Driving: pedestrians, parked cars
 Severe disruption of reading  cannot predict the following p
g
letters or words
 Cannot direct saccades to next word, do not finish line
 finger or strip at end of line; rotate text to read vertically?
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f h
h
Left homonymous hemianopia
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Left homonymous hemianopia
Effects on ADLs
Driving: pedestrians, cars entering from side roads
Shopping centres
Reading: 


Snellen chart: misses first letters
Finding next line when reading
Misread longer words:
g
 finger at commencement of next line, typoscopes, strip of ribbon along left margin
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Macula splitting vs macula sparing
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can cause egocentric
Hemianopia can cause egocentric visual midline shifts
 Perceived visual straight ahead is shifted to the side, and/or 



up or down
Resultant mismatch of visual ‐ spatial midline with facial and body midlines
The person will often lean to one side, forward and/or p
,
/
backward
Often occurs with a hemiparesis
Can affect
Can affect:
 Veering to one side
 Visually guided motor skills eg reaching
 Fatigue, stress, visual “shutdown”
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Prisms for midline shift
 Yoked prisms beneficial to re‐align body and vision centrally
 ‘Skewing’ of space due to field loss shifts visual mid‐
‘Sk i ’ f d fi ld l hif i l id
line away from body mid‐line
 Affects posture, balance because of various head, Affects posture balance because of various head shoulder, body turns or tilts‐adaptations!
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neglect /
Visuospatial neglect / Unilateral spatial inattention
 “Lack of awareness of sensory events in the contralesional side of space”.
 Behaviour as if half the spatial world (and body) does B h i if h lf h i l ld ( d b d ) d not exist.
 Most common after middle cerebral artery stroke. Most common after middle cerebral artery stroke Typically left “neglect” from right posterior parietal cortex
 Can be associated with a left hemianopia, or isolated.
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Visual neglect & walking
 Patient with left hemianopia veers to the left and exhibits head turn or eye scanning
 Patient with left neglect veers to the right, and does P i i h l f l h i h d d not show a head turn or eye scan, since the left side of the world does not exist
 Often show a visual midline shift to RIGHT
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Diagnosis in practice
 Visual field loss may not have been previously diagnosed in a client  Suggests possibly unknown pathology which requires S
ibl k
h l
hi h i investigation and diagnosis, together with other healthcare practitioners
 Comanagement with rehabilitation professionals to maximise performance:
p
 Activities of daily living (ADL)
 Rehabilitation progress ICBO 2010
Functional rehabilitation and
Functional rehabilitation and prognosis
 Communication with client, carers and other rehabilitation professionals
 Reports of potential impact on rehabilitation therapies
R
f i l i
h bili i h
i
 Optometric management:
 Vision therapy
Vi i th
 Use of optical aids
 Compensatory strategies
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Benefits of rehabilitation
Benefits of rehabilitation for field defects
 Increased safety, decreased risk of secondary injury
 Improved function in ADL’s
 Reading
 Walking, shopping
 Driving
 Occupational demands
 Home ADL’s
 Improved overall and specific rehabilitation progress
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Field awareness prism systems
 Gottlieb Visual Field Awareness system
 Peli prisms
 Fresnel prism
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Gottlieb Visual Field Awareness system
 Looking into the prism brings the lost field i i
into view
 One study showed average expansion of 13.25 degrees  Training is strongly g
gy
recommended
Gottlieb DD et al. Neuro‐optometric facilitation of Gottlieb DD et al
Neuro optometric facilitation of vision recovery after acquired brain injury. NeuroRehabilitation 1998;11:175‐199.
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Reference
 Treatment of hemianopsia and “neglect” – a case report on the vision rehabilitation process utilising the Visual Field Awareness System Gottlieb et al
Visual Field Awareness System. Gottlieb et al
 J Low Vision Neuro‐Optometric Rehabilitation, vol J Low Vision Neuro Optometric Rehabilitation vol 11(1):6‐12.
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split plastic prisms above and
Peli split plastic prisms above and below primary gaze
 Place images from field 
Peli E. Field expansion for homonymous hemianopsia by optically induced peripheral exotropia Optom Vis Sci 2000;77:453‐464.
exotropia. Optom Vis Sci
2000;77:453 464
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


loss onto existing field monocularly
Superior & inferior ghost images in periphery act as cues, leading head l di h d and eye movement
Fresnel trials initiallyy
8x22 mm 40D segments
Can expand effective field by up to 20 degrees
Fresnel Prisms  For mobility – spot or hemi prism on edge of “lost” field with scanning training to look detect move look, detect, move. Increases awareness on blind side to find on “blind” side to find objects again to move safely through space.
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Advantages and disadvantages of
Advantages and disadvantages of Fresnel prisms
 Light, great for instant  Increasing prism power trial
i l
 Easily applied and removed
 Cosmetically acceptable
causes blur
bl
 Colour and reflection issues
 Monocular use causes diplopia with scanning
p p
g
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1: N, 69
 Probable focal ischaemia
following heart operation
 Bangs into people on right side, uses cane to keep id k people away
 Visual fields R homonymous hemianopsia
with macula sparing; sloping margins are an advantage in adapting to prism
i
 Treatment R temporal Fresnel spotting prism
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Spotting prism (Gottlieb,Peli)
 Gottlieb suggests 18 pd base out disc just temporal to right limbus on right spectacle lens; used as spotting prism to look into by slight right gaze, locate objects, then turn head to right and move prism out of way
 Trialled 20 then 25 pd Fresnel 10c piece size
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Results
 Walks confidently in shopping centre
 Drives motorised “gofer”
 Notices diplopic vision is dominated by real vision
 Discarded white stick
 Scanning automatically
 Uses for scanning, not viewing
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2: B age 40
 R intracerebral haemorrhage involving temporal, frontal 



and parietal areas, craniotomy and craniectomy, secondary myocardial infarction seizures
secondary myocardial infarction, seizures
Hypertension primary
Left hemiplegia and hemianopia
Wheelchair
Referral: impaired visual spatial sense and midline
p
p
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 Confrontation: left homonymous hemianopia
 Midline: 2 cms shift to left, head turn
 Trials: 5 PD bases left shifts midline to right
 4 pd bases left straightens head and posture, optimal midline, improves awareness of objects on left side
idli i
f bj
l f id
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Progress
 Not bumping into things as much, more aware of left side
 Can pick up left side of page better
C i k l f id f b
 More function of left side
 Saccades less random with quick refixation
S
d l d i h i k fi i through h
h localisation
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Yoked prisms for Visual Midline
Yoked prisms for Visual Midline Shift, & sighting prism for field loss
 When there is a combination of an homonymous hemianopia and a visual midline shift (hemi, nerve palsy monocular VA issues)
palsy, monocular VA issues)
 May combine:
 Lateral yoked prism to normalise visual midline
 Optical aids for increased field awareness
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Progress
 (‐) diplopia
 Uses glasses to remind of lleft side
f id
 Trials show 15 pd Base out left eye temporal area improves awareness and saccades to left
 Reading fluently and easily to next lines
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Summary
 Visual field loss is not a life sentence in relation to 



ADLs Careful assessment by all means possible of visual fields
Understand practical effects of loss on ADL and rehabilitation
Use lenses, prisms (yoked and spot) to improve awareness and functioning
Learn through experience with your patients
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