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Nystagmus Flashcards

1
Q

What is nystagmus?

A

abnormal fixation, rhythmic oscillation, congenital or acquired

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2
Q

Is nystagmus voluntary or involuntary?

A

involuntary

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3
Q

What are two properties describing nystagmus?

A

waveform and direction

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4
Q

What does acquired nystagmus show that congenital does not?

A

oscillopsia

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5
Q

What are the four waveforms?

A

pendular, jerk, gaze holding/latent-manifest, and vestibular

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6
Q

Describe pendular waveform

A

smooth back and forth, velocity similar in both directions, amp can vary

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7
Q

Describe jerk waveform

A

slow phase and quick re-fixation, gets faster as slow phase gets more eccentric

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8
Q

Describe gaze-holding/latent manifest waveform

A

type of jerk, gets slower as slow phase gets more eccentric

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9
Q

Describe vestibular waveform

A

steady velocity throughout

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10
Q

What is pendular nystagmus amp, frequency, and peak velocity?

A

0.5-10 degrees, 2-8 Hz, up to 100 deg/sec

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11
Q

T/F congenital pendular nystagmus is usually horizontal

A

true

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12
Q

What is congenital pendular nystagmus associated with?

A

albinism

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13
Q

Acquired nystagmus often has what direction?

A

vertical and torsional with more variability in waveform

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14
Q

What can cause acquired nystagmus?

A

myelin diseases, central brainstem stroke, monocular vision loss

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15
Q

Congenital nystagmus can fall into what two broad categories?

A

associated with detectable ocular anomaly OR no anomaly aka idiopathic

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16
Q

What percent of nystagmus patients have strabismus?

A

15%

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17
Q

What conditions are associated with ocular anomolies?

A

congenital cataracts, foveal hypoplasia, deprivation amblyopia, optic atrophy

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18
Q

What are the three basic types of jerk nystagmus?

A

congenital, gaze-evoked, vestibular

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19
Q

What is congenital jerk nystagmus?

A

arises during first year, horizontal and conjugate (both eyes move together), reduced with convergence, worsened with intentional monocular fixation

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20
Q

What is the amp, frequency, and slow phase velocity congenital jerk nystagmus?

A

0.25-5 deg, 1-5 Hz, up to 100 deg/sec

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21
Q

Do patients with congenital jerk nystagmus have 20/20 VA?

A

it depends on development, foveal hypoplasia, abnormal visual experience, etc

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22
Q

What is the treatment for congenital jerk nystagmus?

A

yoked of BO prims, surgery, VT, biofeedback, contact lenses

23
Q

What are two types of congenital jerk nystagmus?

A

latent and manifest latent

24
Q

T/F traditional latent is not seen binocularly

25
What are two types of manifest latent nystagmus?
pendular or jerk with both eyes open
26
T/F latent jerk nystagmus gets better monocularly
false, worse with one eye covered
27
Describe the movement of latent jerk nystagmus with one eye occluded
drifts toward occluded eye with refixation toward viewing eye, slow phase then fast phase
28
How do you label a monocular latent jerk nystagmus?
label by the fast phase (toward the open eye)
29
What is a gaze-evoked jerk nystagmus?
gaze-holding, velocity decreases during slow phase
30
What conditions cause gaze-evoked jerk nystagmus?
drug use, cerebellar disorder, vestibular disorder, multiple sclerosis
31
T/F endpoint nystagmus is normal
true
32
Why is endpoint nystagmus evoked?
from attempted maintenance of extreme eye position
33
What is the most common form of nystagmus?
gaze-evoked
34
Describe the motion of gaze-evoked nystagmus
slow phase away from eccentric position (trying to hold eccentric gaze) then fast phase snaps back out
35
T/F gaze evoked nystagmus is due to a deficient eye position signal in the neural integrator network
true
36
How can end point nystagmus and gaze-evoked nystagmus be differentiated?
endpoint has lower intensity and is not associated with other ocular motor abnormalities
37
What is vestibular jerk nystagmus?
central or peripheral, constant velocity slow phase, made worse by head position change
38
What direction is central vestibular jerk nystagmus?
usually vertical
39
What direction is peripheral vestibular jerk nystagmus?
usually horizontal
40
How does fixation effect vestibular jerk nystagmus?
suppresses peripheral but does not suppress central
41
What is spasmus nutans?
rare condition w/ triad of nystagmus, head nodding and torticollis, onset 3-15 months and disappearance by 3-4 years
42
Describe spasmus nutans
small amplitude, high frequency oscillations, usually bilateral but can be monocular, asymmetric and horizontal and variable in different positions of gaze
43
What is periodic alternating nystagmus?
conjugate, horizontal jerk nystagmus with fast phase in one direction for 1-2 minutes, intervening neutral phase for 10-20 sec and then opposite direction beating 1-2 minutes, repeat
44
What is the mechanisms of periodic alternating nystagmus?
disruption of vestibulo-ocular tracts at the pontomedullary junction
45
What is INO (abducting nystagmus of internuclear ophthalmoplegia?
nystagmus in the abducting eye contralateral to a medial longitudinal fasciculus lesion
46
What must spasmus nutans be differentiated from?
congenital nystagmus and intracranial tumors which also result in head nodding and nystagmus
47
What are the two types of caloric testing and what direction is the eye movement?
warm water: slow away fast back; cold water: slow toward, fast away
48
What is COWS in caloric testing?
cold opposite warm same (describing the direction of the fast movements)
49
When does foveation occur during pendular nystagmus?
when velocity is the slowest (when pendulum movement reverses direction)
50
When does foveation occur during jerk nystagmus?
immediately after the saccade or fast portion
51
Why is prism used to treat nystagmus?
can identify null point and use prism to move target , will dampen nystagmus
52
Which VA was better with prism treatment?
distance better than near
53
T/F you cannot use auditory feedback with nystagmus
false

Ocular Motility (13 decks)

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