Flashcards in Block 12 Deck (160)
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1
Involuntary rhythmic oscillation of 1 or both eyes
Nystagmus
2
Can be a sign of visual pathway lesion or an ocular control abnormality
Nystagmus
3
Type of waveform of nystagmus: has both quick and slow components
Jerk
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Which way is the slow phase in a jerk nystagmus
Away from the target
5
Which way is the fast fast in jerk nystagmus
Back to fixation
6
How is jerk nystagmus characterized
Direction of fast phase
7
Type of waveform of nystagmus: to and fro movements of equal velocity in each direction
Pendualr
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Type of waveform of nystagmus: doesn’t have a fast phase
Pendular
9
Which phase of jerk nystagmus reflects the abnormality
Slow
10
Slow movement to the right with a fast corrective jerk movement to the left
Left jerk nystagmus
11
The size/extent of the movement during nystagmus is known as the
Amplitude
12
From what 2 points in nystagmus is the amplitude measured
From the start of the drift away tot he start of the corrective movement
13
Number of oscillations per unit time in nystagmus
Frequency
14
Fast frequency nystagmus is how quick
>2Hz
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1 Hz equals
1cyc/sec
- a full rotation in 1 second
16
Frequency of a slow nystagmus is what time
<2Hz
- need a slit lamp to view
17
Where the intensity of the nystagmus diminishes and the VA improves
- may be associated with head position
Null point
18
With latent nystagmus seen with occlusion, the fast phase is towards
Uncovered eye
19
What does latent nystagmus usually indicated
A congenital condition
20
Anterior seg conditions with nystagmus (3)
Congenital cataract
Congenital glaucoma
Iridocorneal dysgenesis (didnt form properly)
21
Foveal condition associated with nystagmus
Foveal hypoplasia in albinism (flattening)
22
Optic nerve/retinal disorders associated with nystagmus
Coloboma of ON head (fissure doesn’t close)
ON hypoplasia
Toxoplasmosis
23
Do children with congenital nystagmus usually complain about issues
No
24
Nystagmus from motor coordination
Less VA loss (better VA)
25
Nystagmus from sensory issues
More VA loss (worse VA)
26
Do you allow patients to use their preferred head position when doing VAs?
Yes bc this will allow you to asses true functional vision
27
When doing monocular VAs, you may have to use a high plus lens to blur instead of occlude because
You need to allow fusion so that the jerk nystagmus intensity doesn’t increase
28
When refracting pts with nystagmus, do you use the phoropter
No, need to see the nystagmus
- use trial lenses or a lens bar
29
CT may be difficult in patients with nystagmus. What can you use to determine if the reflexes appear symmetrical
Hirschberg/krimsky
Bruckner
30
