Nystagmus

Question 1

Features of infantile nystagmus

Answer 1

• uniplanar
• near Vision better
• worse in distance
• less for near
• head posture
• null position (point of lest amplitude)
• head nodding to cancel out movement
• neutral point is reversal point
• no oscillopsia
• no vertigo

Question 2

Other causes of nystagmus

Answer 2

• albinism
• rod defects
• achromatopsia
• rods and cones - lebers amaurosis
• optic nerve hypoplasia
• achiasma
• methodone

Question 3

Surgical treatment of nystagmus

Answer 3

Head posture
- end gaze blocking
- 4 muscles recess/resect
- move null position

Question 4

Adapting to low vision with nystagmus

Answer 4

• optical correction
• educational material visible
• work within communication distance for facial expression
• phone camera

Question 5

Causes of early onset aquired nystagmus

Answer 5

• optic chaism tumours
• posterior fossa tumours

Question 6

Nystagmus phases

Answer 6

• Slow phase - eyes drift away from fixation point slowly
• Rapid phase - saccadic movement back to fixation point

Described by:
- Amplitude (how far eyes move) - coarse or fine
- Frequency (how fast eyes move) - low, moderate, high

Question 7

Nystagmus eye movements

Answer 7

• Jerk
  
  • Slow drift, fast saccadic correction (zig-zag)
• Pendular (most common)
  
  • Non-saccadic in both directions, slow (squiggly line)
• Mixed
  
  • Different eye movement on different positions of gaze
  • e.g. pendular in primary position and jerk on lateral gaze

Question 8

Nystagmus types and causes

Answer 8

• See-Saw (vertical nystagmus where one eye goes up and the other goes down)
  
  • Midbrain lesions
  • Pituitary tumours
  • Severe visual loss
• Downbeat (eye drifts up slowly and then a quick down motion to the centre)
  
  • Cerebellum lesions
  • Medulla lesions
  • Idiopathic
• Upbeat (eye drifts down slowly and then a quick up motion to the centre)
  
  • Medullary lesions
  • Cerebellum lesions
  • Benign positional paroxysmal vertigo
• Abducting nystagmus of INO
  
  • Demyelination
  • Brainstem stroke
• Periodic Alternating (alternating eye movement)
  
  • Arnold-Chiari
  • Demyelination
  • Trauma
  • Encephalitis
  • Syphilis
  • Posterior fossa tumours
  • Visual deprivation
• Pendular nystagmus
  
  • Demyelination
  • INO
  • Brain stem dysfunction
• Spasmus Nutans
  
  • Idiopathic in children
  • Glioma
• Gaze-evoked (no nystagmus in primary position but when px moves their eyes they can get nystagmus in other positions of gaze
  
  • Drugs
  • Alcohol