Visual Fields Flashcards
! Rule out VF defect
! Document VF defect
! Localize pathology in visual pathway ! Monitor disease process over time
Reasons for performing perimetry
superior 60
inferior 75
temporal 100
nasal 60
normal limits of vf
! Corresponds to the optic nerve
! 15 ̊ temporal to point of fixation
! 1.5 ̊ below horizontal meridian
! Diameter:
! 5 ̊ horizontal
! 7 ̊ vertical
physiologic blind spot
VF examination strategies
kinetic perimetry
! Tests differential light sensitivities of specific retinal locations
on a fixed grid pattern
! Spacing between points varies on type of examination area
static perimetry
! Grey scale
! Decibel sensitivity plot
! Total deviation numerical & probability plot
! Numerical plot in decibels
! Compares sensitivity at each point to normal population of similar age
! Pattern deviation numerical & probability plot
! Adjusts for generalized depression or elevation of VF
automated static perimetric plots
! Fixation losses
! False positives
! False negatives
reliability indices
! 30-2 ! 24-2 ! 10-2 ! Macular ! Nasal step: additional 12 locations up to 50 degrees nasal
humphrey vfa
! Generalized reduction in retinal sensitivity
vf defect depression
! Focal area of reduced sensitivity surrounded by an area of
normal sensitivity
! Absolute : defect persists when maximum stimulus is used (ie. blind spot)
! Relative: defect present to weaker stimulus, but disappears with brighter stimulus
scotoma vf defect
where are the axons in the optic nerve
behind the orbit and
near the chiasm
! Containscrossed(nasal)anduncrossed (temporal) fibers
! Typically situated directly above sella turcica
! Superior: hypothalamus and floor of third ventricle
! Inferior:pituitarygland
! Lateral: IC A and cavernous sinus
chiasmal anatomy
! Pituitarytumorinvolves
chiasm first
central: directly over sella
! Pituitarytumorinvolves
chiasm first
prefixed: anterior to sella
! Pituitary tumor damages optic nerve(s) first
post fixed: posterior to sella
! Extend from chiasm to LGB
! Fibers from temporal half of ipsilateral eye and nasal half
of contralateral eye
! Visual fields will produce homonymous hemianopia ! Typically incongruous
optic tracts
! Relaynucleus ! Positionedalonglateralaspectof midbrain ! Further organization of fibers ! VF lesions will be hemianopic (congruous or incongruous)
lateral geniculate body
! SuperiorVF
! MeyersLoop:temporallobe
! Temporal lobe lesions: “pie in thesky”
inferior fibers (optic radiations)
! InferiorVF
! Loopposteriorlythrough parietal lobe
! Parietallobelesions:“pieonthe floor”
superior fibers
! Medial aspect of occipital lobe ! Significant input from macula
! Central 30 degrees occupy 83% of the striate cortex
visual cortex
blood supply of optic chiasm
circle of willis
blood supply of visual cortex
! Posterior cerebral artery
! Middle cerebral artery
! Unilateral ! Invades vertical hemianopic line ! May respect horizontal line d/t separation of fiber bundles ! Complete/partial vision loss ! Color vision defect ! RAPD
lesions of optic nerve clinical findings
! Optic neuritis ! Trauma ! Space occupying lesion (adenoma, glioma, meningioma) ! Ischemic optic atrophy (NAION, AION) ! Papilledema ! Nutritional/toxic insult ! Glaucoma
causes of lesions of optic nerve
! Vision loss ! Typically painless ! Progressive ! Bilateral asymmetric ! Headache possible ! Stretching of diaphragma sella
chiasmal disease
! Signs ! +/- VA loss ! VF defect ! Optic atrophy ! APD ! Dyschromatopsia ! +/- endocrine dysfunction ! Diplopia: if adjacent cavernous sinus is involved
chiasmal disease signs
! Pituitary adenoma ! Suprasellar meningioma ! ICA aneurysm ! Optic nerve glioma ! Uncommon: ! Trauma ! Inflammation
chiasmal disease: etiology
! Causes: compressive disease ! Aka junctional scotoma due to compression of Von Willebrand’s Knee ! Due to post-fixed chiasm ! Clinical findings ! Ipsilateral RAPD ! +/-diplopia ! Ipsilateralcentralscotoma ! Contralateralsuperiortemporaldefec
anterior chiasmal syndrome
! Pre-fixed chiasm
! Macular fibers cross posteriorly in chiasm
! Tumor impinges on posterior chiasm and optic tracts
! Clinical findings
! Central bitemporal hemianopic defects (nasal macular fibers) ! Homonymous hemianopia due to optic tract compression
posterior chiasmal syndrome
! Causes
! Suprasellar aneurysm
! Pituitary gland tumors
! Suprasellar meningioma and glioma
! Third ventricular dilation due to obstructive hydrocephalus
! Clinical presentation ! Bitemporal hemianopia ! Bilateral optic atrophy
middle chiasmal syndrome
! Causes
! Distention of 3rd ventricle causing pressure on each side of
chiasma
! ICA aneurysm
! Clinical findings
! Binasal hemianopia ! Partial optic atrophy
lateral chiasmal lesions
! Acromegaly: prominent brows/nose/chins
! Cushing Syndrome: moon face, truncal obesity, buffalo hump ! Galactorrhea
! Amenorrhea
! Decreased libido, infertility
endocrine dysfunction
! Band pallor: common
! Diffuse pallor
! APD
! Dyschromatopsia
optic atrophy
! MRI with contrast
! Neurosurgical referral ! Endocrine workup
! Monitor visual fields
! Every 4-6 months until stabilization, then annually
chiasmal disease manaement
! Homonymous: nasal VF of one eye and temporal VF of fellow eye
! Congruous: nasal and temporal defects closely resemble each other
! Fibers posterior to chiasm become more segregated in terms of what part of the VF they represent
! Decreased VA not common unless lesion also involves optic nerve or occipital lobes
! Usually due to cardiovascular disease
post chiasmal disease
! Causes: ! Tumors ! Ischemic stroke ! Aneurysms of superior cerebellar or PCA ! Clinical findings: ! +/- congruous hemianopia
optic tract lesions
! Causes: ! Vascular occlusions ! Primary & secondary tumors ! Trauma ! Clinical findings: ! Incomplete incongruous quandranopsias ! Neurologic deficits predominate 
lesions of optic radiations
! Incongruous “pie in the sky” ! Affects Meyer’s Loop: inferior retinal fibers ! Neurologic symptoms ! Seizures ! Hemiparesis ! Hemisensory loss ! Aphasia
temporal lobe lesions
! Incongruous “pie on the floor” ! Affects superior retinal fibers ! Neurologic symptoms ! Hemiplegia ! Hemisensory loss ! Visual neglect ! Aphasia
parietal lobe lesion
! Congruous homonymous hemianopia with macular sparing
middle cerebral artery infarct
! Congruous homonymous macular defect
posterior cerebral artery infarct
! Incongruous homonymous hemianopia
! Fibers segregated into R & L side of visual pathway
! Contralateral APD because temporal VF is 40% larger than nasal VF
! Band optic atrophy
optic tracts
! Congruous
! Very small lesion and very difficult to isolate
LGN post chiasmal vf defects
! Incongruous
! Pie-shaped superior homonymous hemianopia ! Seizures and hallucinations common
! Neurologic symptoms predominate
temporal lobe post chiasmal vf defect
! Congruous, complete or incomplete
! Neurologic symptoms predominate
parietal lobe post chiasmal vf defect
! Absolute congruity
! Superior and inferior fibers completely separated ! Extreme respect for vertical and horizontal midline
! Homonymous central or macula-sparing defects ! Absence of neurologic symptoms
occipital lobe post chiasmal vf defect
