Bv Lec 12 Flashcards

1
Q

What’s nystagmus

A

Rhythmic oscillation if eyes about one or more of its visual axis

NOT A DIAGNOSIS ON ITS OWN BUT A SIGN ID NEUROLOGICAL ANOMALY

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2
Q

Differential diagnosis for nystagmus

A

Opsoclonus

Superior oblique myokymia

Akinetopisa

Visual allesthesia

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3
Q

What are the 3 types of physiological nystagmus (not a disease)

A

End point nystagmus

Post rotational nystagmus

Voluntary nystagmus

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4
Q

How is pathological nystagmus classified

A

Onset (congenital/acquired)

Waveform (jerk/pendular)

Cause (cerebellar/labyrinthine)

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5
Q

What are jerk and pendular nystagmus

A

Jerk - slow drift then a fast corrective phase

Pendular - sinusoidal oscillations and approx equal amplitude/velocity

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6
Q

What an example of congenital nystagmus

A

Low vision nystagmus
-lack of fixation reflex secondary to neonatal blindness

  • pure pendular (rare)
  • pendular changes to jerk in versions (majority)

-no AHP

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7
Q

What’s sensory nystagmus

A

Any disease that results in bilateral neonatal blindness

E.g cataract/opacity/ONH atrophy or hypoplasia, retinal disorder

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8
Q

Albinism is a common cause of low vision in young px
What’s the symptoms &
mechanism behind it

A

Reduced VA from fovea hypoplasia

Strabismus from abnormal decussation of ocular fibres (20% temp fibres decussate at chiasm)

Photophobia from iris transillumination

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9
Q

What is idiopathic nystagmus

A

All types of manifest nystagmus without a primary visual defect at birth or in first weeks of life as visual fixation develops

Hereditary and often irregular Xlinked dominant disorder

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10
Q

First 5 Signs of idiopathic nystagmus

A

Develops early infancy

Bilateral horizontal and equal amp

Pendular initially but becomes jerk

Null point so has AHP?

Dampens on convergence

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11
Q

Last 4 signs of idiopathic nystagmus

A

Latent so increases amp on monocular view

Movements abolished in sleep

Oscillopsia rare

Reversed OKN response

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12
Q

Whats latent nystagmus

A

Horizontal jerk nystagmus present when light stimulus to either eye reduced

No observable nystagmus when eye is uncovered and light in BEs

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13
Q

What’s manifest latent nystagmus

A

Horizontal nystagmus present when BEs open but increases in amp when one eye covered

Associated with infantile esotropia

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