Nystagmus

Question 1

What is Nystagmus?

Answer 1

A constant, involuntary oscillation of the eyes

Question 2

What causes nystagmus?

Answer 2

Pathological or physiological

Question 3

How many types of nystagmus are there?

Answer 3

45

Question 4

What are the 3 categories of nystagmus?

Answer 4

1. Physiological

2. Early‐onset 3. Acquired

Question 5

What are the types of physiological nystagmus?

Answer 5

• Opto-kinetic (OKN) nystagmus:
  Eye moves in response to a moving scene (train)
• Vestibular (VOR) nystagmus:
  Response to rotation of the body

-End point nystagmus: when looking in extreme positions of gaze

Question 6

What is early onset nystagmus?

Answer 6

Presents within first few months of life

Question 7

What are the types of early onset nystagmus?

Answer 7

Latent nystagmus, spasmus nutans and infantile nystagmus

Question 8

What is latent nystagmus?

Answer 8

Either only appears when one eye is occluded (latent‐latent nystagmus) or worsens upon occlusion of one eye (manifest‐latent nystagmus).

Question 9

What type of movement is seen in latent nystagmus?

Answer 9

Jerk and the beat direction is always towards the fixating eye. This means that covering the right eye will lead to jerk nystagmus, with both eyes jerking to the left

Switching occlusion to the left eye will reverse the beat direction, so that the eyes now jerk to the right

The eye movements follow Alexander’s law; i.e. when looking in the direction of the quick phase, nystagmus intensity increases

Question 10

What is spasmus nutans?

Answer 10

Rare disorder along with head nodding and abnormal head posture

Question 11

What is spasmus nutans caused by?

Answer 11

idiopathic

Question 12

Does spasmus nutans recover?

Answer 12

Yes ceases spontaneously

Question 13

What is infantile nystagmus?

Answer 13

A constant nystagmus, usually predominantly in the horizontal axis

Question 14

When does infantile nystagmus start?

Answer 14

The condition develops within six months of birth, and persists throughout life

Not usually present at birth

Question 15

What is infantile nystagmus caused by?

Answer 15

A visual system pathology or idiopathic

Question 16

What are features of nystagmus?

Answer 16

Waveform
Null zone
Oscillopsia
Psychological factors
Head shaking
Refractive error

Question 17

What does waveform mean?

Answer 17

The pattern of eye movements seen

Question 18

How many types of waveforms are there?

Answer 18

12

Question 19

What are the 2 main types of waveforms?

Answer 19

Jerk and pendular

Question 20

How can you clinically detect the specific type of waveform a nystagmus is?

Answer 20

High‐speed eye tracking

Question 21

What is null zone?

Answer 21

A jerk nystagmus has a beat direction and if the patients turns their head to the direction of the beat then the nystagmus lessens- this is the null zone

Question 22

How is the null zone helpful?

Answer 22

The patient will adopt a head posture at the null zone where nystagmus is minimised

Question 23

What is Oscillopsia?

Answer 23

perception of the world moving back and forth

Question 24

Who gets Oscillopsia?

Answer 24

Acquired nystagmus more likely to get it or if infantile nystagmus patient is unwell or tired they can also get it

Question 25

What psychological factors affect nystagmus?

Answer 25

If px is stressed, it can intensify their nystagmus

Question 26

Who gets head shaking?

Answer 26

27% of Infantile nystagmus

Question 27

How does head shaking help?

Answer 27

Example:

As they move their head to the left, their eyes go to the right so can make it compensatory where the waveform is reduced

Question 28

What sort of refractive error is seen in infantile nystagmus?

Answer 28

High refractive error due to poor emmetropization, more myopia

With the rule astigmatism

Astigmatism increases with age due to interaction between cornea and eyelids

Question 29

What is acquired nystagmus caused by?

Answer 29

Disease or injury, often to the vestibular or central nervous systems

Question 30

Common cause of acquired nystagmus?

Answer 30

MS or stroke

Question 31

What are the features of a suspect acquired pathology are?

Answer 31

Asymmetry,

A significant vertical component to the nystagmus

Oscillopsia

Saccadic oscillations without any apparent slow phase

Question 32

What questions do you ask in history taking in practice?

Answer 32

How long has nystagmus been present?

Is oscillopsia perceived?

Is there a history of strabismus?

Is there a family history of nystagmus?

Does nystagmus intensity increase with occlusion?

Is the movement symmetrical?

Does beat direction depend on which eye is covered?

Is head shaking present?

Does convergence cause dampening of nystagmus?

Is there a null zone? (Is a head posture used?)

Question 33

How do you do tonometry for nystagmus patient?

Answer 33

Non contact tonometry is difficult so take extra care when doing contact

Take advantage of the patient’s null zone to dampen nystagmus as much as possible

Question 34

How do you do refraction for nystagmus patient?

Answer 34

Phoropters should be avoided in favour of a trial frame, to allow patients to turn their head and view using the null zone

Wide‐aperture trial lenses are preferable although even this may not be sufficient for some patients to obtain the same quality of vision as with glazed spectacles or contact lenses.

Give patients plenty of time to respond

The use of a +10.00 DS lens for occlusion can help prevent increasing nystagmus intensity when measuring monocular VA in individuals with a latent nystagmus component

Question 35

How do you do perimetry?

Answer 35

Using their null zone if available, but due to the constant eye movements, the results should be considered less sensitive to small field defects

Question 36

What are you likely to see on cover test?

Answer 36

Strabismus is present in 64% of individuals with early‐onset nystagmus, with

98% of these cases being horizontal (esotropia or exotropia).

This is particularly the case in latent nystagmus, which is almost always accompanied by a history of squint. .

Question 37

How do you manage nystagmus in primary practice?

Answer 37

Every child first presenting with a nystagmus= refer

Any change in nystagmus= refer

Acquired= urgent referral