Flashcards in Neuro-opthalmic exam Deck (45):
What is considered affarent?
2. contrast sensitivity
3. color vision
What is considered efferent?
1. pupillary function
2. ocular motility
5. facial nerve function
entrance tests look at which nerves?
2, 3, 4, 5, and 6
What does contrast sensitivity test measure
measures residual function loss if patient does well with high contrast targets. Esp in patients who have pale nerves or optic neuritis
what kind of lesions can lead to achromatopsia (absent color vision)
retinal lesion, optic nerve lesion, or cortical lesion
Acquired optic nerve disease usually produces red/green deficiency. What do acquired color perception defects arise from
1. macular lesion
2. retinal lesion
3. optic nerve insult
4. chiasmal lesion
5. retrochiasmal lesion
Which atrophy causes blue yellow deficits
dominant optic atrophy
____% of optic nerve fibers are macular in origin and represent central 20 degrees.
which cortex deals with VA? ventral stream is responsible for what? dorsal stream is responsible for what?
1. striate cortex
2. occipito- temporal (what)
3. occipito- parietal (where)
which three things deal with the ventral stream
1. object identification and recognition
2. alexia - inability to read
3. achromatopsia - color vision loss
which four things deal with the dorsal stream
1. visuospatial processing and localization
2. akinetopsia - impaired motion processing
3. astereopsis - stereo problems
4. visual neglect of left hemifield due to right parietal lobe lesion
Anisicoria is always due to what type of defect?
When do you have to check near response?
If you're doing pupils and there is no light reaction. (There are more near fibers than light fibers).
If pupil size is greater in light then which system is defected
parasympathetic --> lesion in dorsal midbrain
what is dilation lag usually due to
sympathetic denervation (Horner's syndrome)
If you think your patient has an APD what should you go back and check
color vision, contrast, VA's
The marcus gunn swinging flashlight test evaluates optic nerve function and requires only ___ functioning pupil.
What can an APD be caused by
1. unilateral optic nerve/retinal disease
2. asymmetric chiasmal disorders
3. optic tract lesions
what is 1+ indicative of when grading pupils. what is 4+ indicative of
intital constriction, followed by early redilation; amaurotic pupil
what do you measure when looking at eyelids? what is the average palbepral fissure length?
MRD: marginal reflex distance, which is usually 4-5 mm in height and is distance between corneal light reflex and upper lid margin; avg palpebral fissure is 9-12 mm.
how do you assess function of the levator
have pt look down and hold the eyebrow to prevent the frontal muscle from elevating the lid. Measure from lower lid margin. Normal lid elevation is greater than 12 mm.
when will levator function be reduced
2. CN3 palsy
4. myotonic dystrophy
5. congenital ptosis
dissociation between voluntary and emotional stimuli of facial movement is usually due to ______ lesions
what helps differentiate nuclear and infra nuclear lesions from supra nuclear lesions
bells phenomenon (preserved in supranuclear lesion)
What does VOR assess
how well a patient can fixate during brief head/body movements. In supra nuclear lesions, VOR is present while EOMS are affected.
What is OKN good for
localizes site of lesion; parietal lobe --> reduced ipsilateral OKN
what is forced duction test good for
differentiates paretic (nerve problem) vs restrictive eye movements (inflamed medial rectus).
what is indicative of a positive forced duction test? what about negative?
positive: can't move eye as far out as it should go (due to restrictive antagonist muscle)
negative: easily move eye manually in direction of restriction (nerve issue, due to weak agonist muscle)
what are signs of an orbital process
1. proptosis (use expopthalmeter)
2. conjunctival injection
3. multiple limited EOMs
when do you suspect proptosis
anything above 24 mm or inter eye difference of greater than 2 mm.
_____ is the inability to follow a motor command that is not caused by a motor deficit or language impairment
apraxia; caused by deficit in higher order planning
How do you test for CN 1?
test each nostril sep with alcohol swab, coffee, or perfue
How do you test for CN II
VA, color vision, VF, and pupils
How do you test for CN III
EOMs, lid position, pupils
How do you test for CN IV
How do you test for CN V
sensory: facial sensation or corneal blink reflex
motor: have pt move jaw against resistance of your hand.
How do you test for CN VI
How do you test for CN VII
Motor: have them close their eyes and try to pry their eyes open. forehead wrinking, smiling,
Lacrimation: schirmer testing
taste: put salt or pepper on each side of their tongue
How do you test for CN VIII
1. Rinne test: tuning fork placed on mastoid process
-Sensori-neural loss: air and bone conduction are reduced.
-Conductive loss: air conduction is reduced
2. Weber test: tuning fork placed in middle of forehead.
-Sensori-neural: sound localized to good ear
-Conductive loss: sound localized to affected side
How to test for IX and X
voice is not hoarse (X), uvula is midline, palate elevates symmetrically
How to test for XI
head turn and shoulder elevation
How to test for CN XII
What does damage to cerebellum result in
2. incoordination of speech (apraxia)
3. incoordination of limbs and gait (ataxia)
How do you test for cerebellar dysfunction
1. finger nose test: limb coordination
-Look for ataxia, or tremor
2. heel -shin test: limb coordination
-Look for wobble, or slide
3. rapid alternating hand movements:
-irregular in amp and timing
4. gait: look for balance, posture, arm swing, and symmetry
-worse when walking in a straight line