What is it?
rhythmic oscillation of one or both eyes
What are the causes of nystagmus. Can be congenital or acquired.
Congenital- albinism/ retinal dystrophies
Acquired- intra-cranial lesions/drug toxicity
2 types of congenital nystagmus.
congenital idiopathic nystagmus ( CIN)- anomoly in motor pathway controlling fine eye movements
sensory deficit nystagmus (SDN) - anomly resulting in poor vision eg cataract, albinism, cone dystrophy, spasmus nutans ( self limiting)
** differentiated by fundus exam + electrodiagnositic techniques
features of congenital nystagmus
similar in both eyes
increase on occlusion
associated strabismus
how to manage congenital nystagmus in childhood
allow px to adopt AHP/CHP (compensatory head posture)
fog other eye during refraction. dont occlude ( worsens mvt)
fundus + VOLK
advise teachers of correct positioning of child in classroom - closer to front/ according to null position
surgery to reduce CHP ( wait till 8 yrs old)
use yorked prisms - base out RE, base in LE = versional mvt so eyes forced into null position. temporary before surgery bz uncomfortable to wear high power for so long
CLs- esp high Rx or eccentric null zone. px avoids looking thru spec lens edges.
What is the null zone?
posiion of gaze of least mvt
if not primary position = lead to CHP
CHP is in opposite position to null position
causes of acquired nystagmus
Mulitple sclerosis
cerebral vascular accident
menieres disease
tumours
head trauma
side effects of drugs
**presents with known onset and oscillopsia
management of acquired nystagmus
removal of tumour
drugs eg. Baclofen, alcohol & cannabis
surgery to null zone
BOTOX- limited success
Last changed8 days ago
