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25 Cards in this Set
- Front
- Back
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T/F The photostress recovery test may be useful in an eye with decreased vision to differentiate between macular and optic nerve disease
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True but onl,y good for vision better than 20/80
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Maculopathy photostress recover time
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90 to 180 sec
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Optic nerve disease photostress recover time
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<60 sec
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T/F The VER is an electrical signal that must be extracted from the simultaneously generated electroencephalogram (EEG)
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TRUE
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T/F In VER the stimulus may consist of either a flash of white light or a pattern, presented either transiently or continuously by pattern reversal.
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TRUE
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What are the two parameters in VER
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"the height of the first positive or upward wave (amplitude)
and the time between stimulus presentation and the appearance of this wave (latency)" |
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T/F VER is not useful for distinguishing optic neuropathy from retinal disorders.
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TRUE
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Which VER is used for VA assessment in nonverbal pts/kids?
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Pattern VER not flash.
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In a pt faking 20/100 vision which fictitious tests are sensitive (3)
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"Fogging refraction
Stereo Acuity Red-green glasses" |
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Which test can be used in any level of factitious loss
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Fogging refraction
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Can an optic tract lesion cause unilateral decreased va
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yes, if incomplete or ON or Chiasm also involved
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Optic tract lesions cause an APD on which side
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contralateral, more than 1/2 fibers cross at chiasm
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How to distinguish supranuclear and infranuclear gaze paresis?
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If the vestibular system can drive the eyes in the direction of the paretic field of gaze, the gaze paresis must be supranuclear in nature. Impaired oculocephalic responses indicate that the infranuclear, end-organ function is responsible for the motor disturbance.
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Describe Bell phenomenon
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Upturning of the eyes upon forceful opening of closed eyelids. Indicates infranuclear common pathway is intact.
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Fat is ___ and water is ___ on T1-weighted images. Describe T2
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Fat is bright and water is dark on T1-weighted images. Opposite on T2
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ON enters intracranial cavity inf to ____ and ____ and medial to ____.
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ON enters intracranial cavity inf to frotal lobe and ACA and medial to the internal carotid artery.
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Lenths of the intraocular, intraorbital, intracanalicular and intracranial portions of the optic nerve.
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intraocular (1), intraorbital (25), intracanalicular (10), and intracranial (17)
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In the chiasm where to macular fibers decussate?
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posterior chiasm
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What is Wilbrand's knee?
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inferior nasal retinal fibers cross in the anterior chiasm and loop anteriorly in the contralateral optic nerve before traveling posteriorly
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How far is the chiasm from the pituitary?
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1mm above the pit
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Fibers from what part of the retina cross first?
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inferior fibers
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In the LGB how are cells segregated in the six layers?
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"ipsilateral ganglion cells synapse in layers 2, 3, and 5
contralateral ganglion cells synapse in layers 1, 4, and 6" |
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What lesion causes the combination of a superior hemianopic contralateral visual field defect and a contralateral hemiparesis?
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Infarct of inferior fibers of the optic radiations that run close to the internal capsule.
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What retrochiasmal location shown can induce a monocular visual field defect with a single lesion alone?
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The temporal 30 degrees of a binocular visual field is perceived by the nasal most retina of the ipsilateral eye only. These “temporal crescents” are represented in the anterior-most occipital lobe. Therefore, a lesion in this area will produce a monocular visual field defect in the far temporal periphery of the contralateral eye, the so-called temporal crescent syndrome. For example, a right anterior occipital lobe lesion would produce a far temporal field defect in the left eye. Similarly, a right posterior occipital lobe lesion may spare the far temporal field in the left eye
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OKN abnormalities are caused by lesions where (2 locations)
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"parietooccipital = slow phase pursuit abnormalities
frontal lobe = fast phase recover abnormalities" |
