nystagmus

see also:

• vertigo - peripheral vs central

• with normal eyesight, while the head rotates about an axis, distant visual images are sustained by rotating eyes in the opposite direction of the respective axis
  • the semicircular canals in the vestibule of the ear sense angular acceleration, and send signals to the nuclei for eye movement in the brain.
  • a signal is relayed to the extraocular muscles to allow one's gaze to fix on an object as the head moves.
• nystagmus occurs when the semicircular canals are stimulated (eg. by means of the caloric test, or by disease) while the head is stationary.
  • the direction of ocular movement is related to the semicircular canal that is being stimulated
  • it may be dependent upon the position of the head positional nystagmus such as occurs with BPV

• a form of involuntary eye movement that is part of the vestibulo-ocular reflex (VOR), characterized by alternating smooth pursuit in one direction and saccadic movement in the other direction.
• optokinetic - induced by looking at moving visual stimuli
• postrotatory nystagmus - as occurs when one spins in a chair continuously and stops suddenly

• uncommon cause
• X-linked infantile nystagmus is associated with mutations of the gene FRMD7
• complete congenital stationary night blindness (CSNB)
  • mutations are found in NYX (nyctalopin) on X chromosome
• incomplete CSNB (iCSNB or CSNB-2)
  • mutations of CACNA1F on the x chromosome, a voltage-gated calcium channel that, when mutated, does not conduct ions.

• most often develops by 2 to 3 months of age
• lack of development of normal eye movement control early in life
• albinism
• aniridia
• very high refractive error, for example, nearsightedness (myopia) or astigmatism
• bilateral congenital cataracts
• bilateral optic nerve hypoplasia
• Leber's congenital amaurosis
• optic nerve or macular disease
• persistent tunica vasculosa lentis
• rod monochromatism

• usually occurs between 6 months and 3 years of age and improves on its own between 2 and 8 years of age

• central nervous system diseases

• peripheral inner ear causes
  • BPV
  • other causes of vertigo - peripheral vs central such as Meniere's, SCDS, labyrinthitis/vestibulitis
  • trochlear nerve malfunction
• CNS causes
  • stroke
    • lateral medullary syndrome
  • thalamic haemorrhage
  • multiple sclerosis (MS)
  • encephalopathy including Wernicke's
  • cerebellar pathology
    • abscess
    • cerebellar ataxia
    • Chiari malformation
    • MS
    • stroke
  • drugs including toxicity
    • anticonvulsants such as phenytoin
    • ethanol (alcohol and alcohol withdrawal)
    • lignocaine
    • ketamine
    • amphetamines and related psychostimulant substances
    • lithium carbonate
    • pregabalin
    • barbiturates
    • benzodiazepines
    • MDMA, PCP
    • nitrous oxide
    • salicylates
    • SSRI/SNRI antidepressants
  • brain tumours
  • sleep deprivation
  • exposure to strong magnetic fields eg. MRI