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Questions and Answers
What does the mnemonic DWARF stand for in the context of recording nystagmus?
What does the mnemonic DWARF stand for in the context of recording nystagmus?
Direction, Waveform, Amplitude, Reducing direction, Frequency
What are some characteristics of nystagmus that are important to assess? (Select all that apply)
What are some characteristics of nystagmus that are important to assess? (Select all that apply)
What type of lens can be used during visual acuity measurement to avoid inducing latent nystagmus? Use a _____ lens on one eye.
What type of lens can be used during visual acuity measurement to avoid inducing latent nystagmus? Use a _____ lens on one eye.
Red
The presence of a slow phase in nystagmus indicates a saccadic intrusion. True or False?
The presence of a slow phase in nystagmus indicates a saccadic intrusion. True or False?
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What are some management options for nystagmus?
What are some management options for nystagmus?
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What is nystagmus characterized by?
What is nystagmus characterized by?
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What are the possible mechanisms that can cause nystagmus?
What are the possible mechanisms that can cause nystagmus?
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Physiological nystagmus is found in people with a disease condition.
Physiological nystagmus is found in people with a disease condition.
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Optokinetic nystagmus is a movement in response to large, moving __________ fields.
Optokinetic nystagmus is a movement in response to large, moving __________ fields.
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Match the following types of nystagmus with their descriptions:
Match the following types of nystagmus with their descriptions:
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What is oscillopsia?
What is oscillopsia?
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What are some symptoms of acquired nystagmus?
What are some symptoms of acquired nystagmus?
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What causes peripheral vestibular nystagmus?
What causes peripheral vestibular nystagmus?
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Tinnitus or deafness is usually present in central vestibular nystagmus.
Tinnitus or deafness is usually present in central vestibular nystagmus.
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Acquired pendular nystagmus often results in elliptical or circular nystagmus due to slow-phase eye movements in horizontal, vertical, and _________ planes.
Acquired pendular nystagmus often results in elliptical or circular nystagmus due to slow-phase eye movements in horizontal, vertical, and _________ planes.
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Study Notes
Nystagmus
- Nystagmus is a type of involuntary, regular, and rhythmic shaking or oscillating motion of the eyes.
- It can be classified into pendular and jerk types.
Mechanism of Nystagmus
- Nystagmus occurs due to a disturbance in:
- Visual fixation
- Vestibular ocular reflex
- Neuro integration (ocular movement)
Types of Nystagmus
- Pendular nystagmus:
- Speed of motion of the eyes is the same in all directions
- Jerk nystagmus:
- Slow and fast phase
- Eyes move slowly in one direction and then seem to jerk back in the other direction
Characteristics of Nystagmus
- Can be:
- Unilateral or bilateral
- Congenital or acquired
- Horizontal, vertical, or torsional or combined
- Conjugate or disconjugate
- Latent or manifest
- Physiological or pathological
Classification of Nystagmus
- Physiological nystagmus:
- Found in normal people
- Not caused by any disease condition
- Can be used as a diagnostic tool
- Acquired forms of nystagmus:
- Due to diseases or disorders
Physiological Nystagmus
- Types of physiological nystagmus:
- Vestibular ocular reflex
- Optokinetic nystagmus
- Caloric nystagmus
- Post-rotatory nystagmus
Vestibulo-ocular Reflex
- A reflexive movement of the eye that keeps the visual image stable on the retina during brief, high-frequency rotation of the head
- Controlled by the vestibular system of the inner ears
Optokinetic Nystagmus
- A physiologic movement of the eyes in response to large, moving visual fields
- Asymmetry of the OKN may suggest lesions of the cerebrum or parietal lobe
Caloric Nystagmus
- A type of VOR (vestibulo-ocular reflex) that is elicited by stimulating the horizontal semicircular canal with either warm or cold water in the ear
- In normal subjects, when cold water is placed in one ear, the eyes will slowly turn toward the ear with the horizontal fast phase away from the ear
- Absence of caloric nystagmus may indicate brain death
Post-rotatory Nystagmus
- A reflexive, transient, conjugate, jerk nystagmus that occurs after the whole body of a subject is passively rotated about the z-axis and then decelerated to rest
- The nystagmus is in the opposite direction of the previous rotation
Early Onset Nystagmus
- Types of early onset nystagmus:
- Infantile idiopathic or congenital nystagmus
- Sensory nystagmus
- Latent nystagmus
- Spasmus nutans
- Monocular nystagmus of childhood
Infantile Idiopathic Nystagmus
- Also known as congenital (motor) nystagmus
- Most common type of nystagmus seen in young patients
- Cause is unknown
- Characteristics:
- Convergence and eye closure dampen
- Oscillopsia absent
- Null point present
- Increases in foveation time and increases the VA
- Gaze position does not change the horizontal direction of the nystagmus
- Equal amplitude and fixation in each eye
- Near acuity is good
- Inversion of the OKN response
- Turning of head to achieve null point
- Abolishes in sleep
- Latent nystagmus occurs
Sensory Nystagmus
- Caused by abnormalities of the afferent visual system
- Usually seen in 3-4 months olds
- Accompanied by:
- Achromatopsia
- Optic nerve hypoplasia
- Ocular albinism
- Brain injury
Latent Nystagmus
- Also known as fusion maldevelopment nystagmus
- Benign, early onset conjugate horizontal jerk-nystagmus
- Only manifests after occlusion of one eye
- Characteristics:
- Direction of the nystagmus is toward the uncovered eye
- Vision is better binocularly than monocularly
- Decreases with age
- Associated with infantile esotropia and dissociated vertical deviation
Spasmus Nutans
- Rare condition with clinical triad of nystagmus
- Onset from 3 to 15 months and disappears between 3 to 4 years of age
- Characteristics:
- Small amplitude and high frequency of oscillation
- Usually bilateral
- Can be unilateral or asymmetrical
- Caused by chiasmal disorder
Monocular Nystagmus
- Type of nystagmus that involves the same eye at all times in a child
- Causes:
- Longstanding poor vision in one eye
- Amblyopia
- Optic neuropathy
- Dense cataract
- Can be inhibited by convergence or fixation
Acquired Nystagmus
- Can develop six months after birth
- Usually vertical or torsional
- Causes:
- Diseases and disorders of the central nervous system
- Idiopathic nystagmus
- Metabolic disorders
- Alcohol
- Drug toxicity
- Stroke
Symptoms of Acquired Nystagmus
- Oscillopsia
- Decreased acuity
- Nausea or vomiting
- Vertigo
- Coexisting neurological defect
Types of Acquired Nystagmus
- Nystagmus due to Defective Gaze-holding
- Peripheral Vestibular Nystagmus
- Central Vestibular Nystagmus
- Acquired Pendular Nystagmus
Causes of Nystagmus
- Lack of development of normal eye movement control early in life
- Albinism
- Very high refractive error
- Congenital cataract
- Inflammation of the inner ear
- Medications
- Diseases of the CNS
- Alcohol
- Vertigo
Signs of Nystagmus
- Involuntary eye movement
- Objects may appear blurry and shaky
- Nighttime vision problems or sensitivity to light
- Balance and dizziness
Assessment of Nystagmus
- Check for general ocular health
- Head or ocular trauma
- Birth history
- Present and past medication history
- Systemic health history
- Any associated symptoms
Recording Nystagmus
- Use the mnemonic DWARF
- Direction
- Waveform
- Amplitude
- Reducing direction
- Frequency
- Characteristics
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Description
Learn about the causes, types, and characteristics of nystagmus, and how to assess and manage patients with this condition. Understand the mechanism of nystagmus and its effects on the eyes.
