Block 12 Flashcards
What is nystagmus
Involuntary rhythmic oscillation of one or both eyes
What can nystagmus be a sign of
Visual pathway lesion
Ocular control abnormality
What are the characteristics of nystagmus
Movement in all gazes Convergence Unilateral/bilateral Conjugate of disconjugate Congenital or acquired
Shakingm dancing, jerking, wobbling eyes
What is jerk
Both quick and slow components.
There is a fast corrective sacade to bring the eye back to the target
Characterized by the direction of the fast component
What is pendular
To and fro movement of equal velocity in each direction
A sinusoidal movement without a fast phase
T/F jerk nystagmus is characterized by the fast phase, but the slow phase of the nystagmus reflects the abnormality
True
What are the directions/movements of nystagmus
Horizontal
Vertical
Torsional
Combination
What is the amplitude of nystagmus
the size/extent of movement between the start and drift away from fixation to start of the corrective movement
Distance travelled during the movement
What is the frequency of nystagmus
Number of oscillations per unit of time
1 Hz
The greater the number of beats the higher the frequency
Frequency > 2Hz
Fast nystagmus
Frequency <2 Hz
Slow nystagmus
Need slit lamp to see
What is the null point
Where the intensity of the nystagmus diminishes and VA improves. This may be associated with an anomalous head movement
What does occlusion do to nystagmus
The fast phase is towards the uncovered eye
Amplitude and frequency increase
Latent component usually indicates a congenital condition
What are some causes of nystagmus
Genetics
Developmental abnormalities
Ocular pathology/conditions
What are some anterior segment conditions associated with nystagmus
Congenital cataract
Congenital glaucoma
Iridocorneal dysgenesis
What foveal disease can nystagmus be associated with
Foveal hypoplasia
What optic nerve disorders are associated with nystagmus
Coloboma
Optic nerve hypoplasia
Toxoplasmosis
What are physiological nystagmus
Endpoint EOM
Rotational
Caloric
OKN
What are pathological nystagmus
Congenital Latent/manifest Acquired Spasmus nutans Vestibular Gaze paretic See-saw Convergence-retraction Downbeat
What do you want to know on case history
Onset?
Any associated condtions
Variable frequency/amplitude/head position/ null point, head nodding
Any symptoms?
What are some symptoms of nystagmus
VA Asthenopia Blurred vision Diplopia HA Vertigo Oscillopsia
What can perinatal history tell you
Is there was a developmental issue that caused it
If there was labor and delivery issues, maternal infections, prematurity, was mom on any medications
T/F children with congenital nystagmus always complain of problems?
False, they rarely do
How is VA affected in nystagmus
It varies from normal to severely impaired depending on the cause
20/30-20/400
Which will cause less VA loss? Motor coordination problem or sensory issues?
Motor coordination problems
Marked decreased VA is more likely in….
Sensory, retinal, optic nerve abnormalities
How should you evaluate VA
D and N D>N Monocular Binocular Chart depends on the age
What is seen during monocular VA when one eye is covered
Latent nystagmus may manifest
Jerk nystagmus intensity increases with the fast phase in the direction of the uncovered eye
For nystagmus you need to evaluate VA without dissociating the eyes or use a plus lens to blur. What lens should be used?
+2-+5
How is nystagmus affected by refractive error
All nystgmus patients should be evaluated for significant error
Correction can improve sensory and motor fusion
How should you evaluate VA in nystagmus
Cycloplege
Have pt look towards their null point
Use trial lenses or lens bar, do not use phoropter
How should you evaluate binocular vision
Move the eyes in 9 gazes
Look at pupils
Hirschberg/krimsky- see if corneal reflex is even
Bruckners
CT (use a +5D lens instead of paddle)
MEM
What is stereo and sensory testing like in nystagmus patients
Variable
Stereo will let you see if pt has a phoria
Do worth 4 dot for suppression
Saccades and pursuits
How would you assess IOP in nystagmus patients
NCT or tonopen
Why is VF testing hard in nystagmus
Because of their change in fixation
What will slit lamp allow you to see in nystagmus
See pattern
Indicate and detect presence of coloboma or transillumination
Need to dilate
OCT the fovea in nystagmus to identify what
Subtle fovea hypoplasia
T/F recent onset and/or systagmus that has not been diagnosed need neuro referrals
True
What is oscillopsia
Sensation of the environment moving
What is vertigo
Feeling of being off balance
What is null point
Position of gaze where the eyes are quiet
What is physiological nystagmus
Conjugate
Jerk nystagmus without other symptoms or decreased vision
Endpoint nystagmus has _____ amplitude, ________ frequency
Small amp
Variable freq
How does endpoint nystagmus appear
Intermittent conjugate jerk
Fast phase is in the direction of gaze
Can be worse when tired
Seen in bth eyes with extreme lateral gaze held for a prolonged time
Symmetrical in right and left gaze
What is rotational nystagmus
Jerk nystagmus due to head or body rotation
Related to endolymph in the semicircular canals
Normal response is slow conjugate eye movement then fast phase in the OPPOSITE direction
What is caloric nystagmus
Conjugate jerk nystagmus produced during the caloric testing of the vestibular system
What is the caloric test
Use of warm and cold water to set up temperature gradients in the semicircular canal causing a convection current in the endolymph, stimulating hair cels
COWS
Cold water in caloric test causes
Nystagmus fast phase towards opposite ear
Warm water caloric test
Nystagmus with fast phase towards the ipsilateral ear
What is optokinetic nystagmus
Slow pursuit eye movement followed by fast corrective saccade because a visual field moves over the retina
It is a conjugate movement maintaining the image of the moving target on the fovea when the head is still
The fast corrective sauced to fixate on a new stripe
When does OKN reflex development
3-5 months of age
What is OKN useful for
Malingering
Uncooperative patients
- OKN
Inconclusive
What does a child with congenial nystagmus show on OKN
Reverse OKN response
Could also sow preserved vertical OKN response
What are pathological nystagmus show
Dissociated movements with excessive oscillations in the presence of other motor abnormalities
Who is affected by congenital nystagmus
Present at or shortly after birth
Twice as common in boys
Likely have a family history
Can occur in people with strabismus as part of an underlying systemic or visual abnormality
What are the etiology of congenital nystagmus
Afferent (sensory 40%)
Efferent (motor 60%)
How does congenital nystagmus appear
Pendulum/jerk nystagmus* Horizontal (even in vertical gaze) Conjugate NO OSCILLOPSIA Amp/freq varies Active fixation, attention, or anxiety can increase nystagmus Could have anomalous head posture if null point is not at primary Can improve with age OKN reverse
How is VA at null point
Very good
The patient will turn or tilt head to decrease nystagmus so the null point will have the best VA
Congenital nystagmus _______ with fixation and _____ with convergence
Increases
Decreases
When do you see latent nystagmus with congenital
When one eye is covered
Afferent etiology for congenital nystagmus
Inadequate image formation that results in failure of development or normal fixation
Severity is correlated to degree of vision loss and pathology
They have poor vision and little prognosis for improvement
What should you consider as causes for afferent congenital nystagmus
Optic atrophy
Optic nerve hypoplasia
Retinal dystrophy
Albinism
Aniridia
Achromatopsia
Cataracts
Efferent etiology in congenital nystagmus
Fixedation and/or motor issues
Better VA than nystagmus from afferent causes
Cosmesis concerns
What is nystagmus blockage syndrome
A patient with congenital nystagmus that later develops esotropia
Develops in patients with congenital nystagmus because of attempts to suppress nystagmus by converging
The esotropia can result with a head turn
Convergence dampens congenital nystagmus
When does nystagmus blockage syndrome reduce or disappear
On adduction of the fixating eye
When does nystagmus blockage syndrome increase
As fixating eye moves toward primary or into abduction
What can nystagmus blockage syndrome look like
CN6 palsy
But they CAN abduct the eye
What is latent nystagmus
Congenital
JERK nystagmus after occlusion of one eye
How does latent nystagmus appear
Horizontal
Fast phase towards the uncovered eye
Benign and isolated
Can be associated with strabismus and amblyopia
Increased with disruption of fusion
Monocular VA decreased
Bingo VA is better
Can be present with other forms of nystagmus
T/F latent nystagmus can also occur with both eyes open but one eye is suppressed.
True
What is spasmus nutans
Starts shortly after birth Pendulum nystagmus Bilateral Reduces by age 5-8 No long term sequelae-often benign
Can be associated with strabismus, amblyopia and developmental delays
What are the characteristics of spasmus nutans
Small fine ampl High frequ/fast Head nodding Torticollis Head nodding and torticollis appears to be compensatory
Why is spasmus nutans a neuro referral
Because you want to make sure they don’t have chiasmal tumors, gloomy, craniopharyngioma, and retinal dystrophies, want to check for optic nerve abnormalities
What is seen-saw nystagmus
Pendular
One eye elevates and intorts while the other depresses and extorts
(The eyes alternate movements)
What I️s see-saw nystagmus associated with
Lesson in suprasellar area
Craniopharyngioma in children
Joubert syndrome
Needs neurology and radiology
What is downbeat nystagmus
Jerk vertical nystagmus n primary, fast phase beats down
Neuro consult
What is down beat nystagmus due to
Craniopharyngioma-cervical junction abnormalities
Chiari malformation
Medications (lithium, tranquilizers)
What is upbeat nystagmus
Jerk vertical nystagmus with fast phase up
What causes upbeat nystagmus
Brainstem abnormalities
Drugs
What is vestibular nystagmus
Horizontal JERK with a rotary element
Oscillopsia, nausea, vertigo, hearing loss
What is vestibular nystagmus associated with
Inner ear or vestibular abnormalities
Dusyfuntion of the peripheral or central vestibular pathway
What is convergence retraction syndrome
Rhythmic convergence and retraction of the eyes when attempting upgaze movement
It is not a true nystagmus because it does not have a slow phase, it has opposing addicting saccades
What causes retraction in convergence retraction syndrome
There is contraction of all EOMs at the same time
What is parinaud syndrome
Dorsal midbrain syndrome. They have pretectal dysfunction, excess onvergence, paralysis of upward gaze
What are the signs of parinaud syndrome
Palsy in upgaze
Eyelid retraction
Pupillary light near dissociation
Convergence-retraction
What is periodic alternating nystagmus
Rare horizontal
Congenital or acquired
The nystagmus changes every 90 seconds
Alternating head turnings to adapt
Can be fixed with surgery if congenital
What are the hallmark sign of periodic alternating nystagmus
Shifting null point
What can periodic alternating nystagmus be seen with
Degenerative process involving the cerebellum
Skew deviation
What is voluntary nystagmus
Rapid with small amplitude and short duration
Pendular
Conjugate
Horizontal
Produced voluntarily by the patient
May run in families
Induced by convergence and there is oscillopsia
Only maintained for a few seconds because of fatigue
Can be part of a spasm of the near reflex
What are the goals of nystagmus management
Improve VA, Ocular motor control, Binocularity, cosmesis, and comfort
What is purpose of refractive correction in nystagmus
To improve the clarity of the retinal image to maintain stead fixation
To lessen the nystagmus
Should be considered as first treatment
What Rx would you prescribe glasses for in nystagmus?
Hyperopia
Astigmatism
Myopia
Hyperopia: 1-2D
Astigmatism: 0.5D or more
Myopia: 0.5D or more
What does plus adds do in nystagmus treatment
It is valuable for improved VA and clarity for near point demands
Aids in accommodation at near
Why would you use minus adds in nystagmus glasses?
To induce convergence since nystagmus can decrease with convergence
You need to make sure that it will not interfere with their binocularity first though
Why are prisms used in nystagmus
To improve binocularity and reduce nystagmus intensity
An improve strabismus, induce convergence, move the null point
How can you induce convergence
Use a small amount of BO prism to stimulate fusional convergence and dampen the nystagmus
How can prisms be used for anaomalous head postures
Yoked prisms can improve VA and slow down the nystagmus
Base is placed in the same direction as the head turn (keeps eyes in null point)
What do yoked prisms do
Shift the image towards the null point
Why would you use ground in prism instead of the Fresnel prism
If Fresnel is used for large prisms there can be a degradation to vision
Ground in vision does not prevent distortion in the vision
How is the prism positioned for nystagmus with a head turn
APEx is placed towards the null point
Base is towards the turn
What is the down side of occlusion in nystagmus
Can lead to latent component manifestation
Why is amblyopia treatment in nystagmus patients difficult
Latent component can show up
Need to consider using plus lenses over better seeing eye (use enough to blur but not enough to disrupt fusion)
Why is vision therapy used in nystagmus
For fusional vergences or to improve motor control and for suppression that could lead to manifest latent nystagmus
When is pharmacological treatment used in nystagmus
When the nystagmus is due to a systemic problem
Oscillopsia, vertigo from vestibular nystagmus, downbeat nystagmus
Gabapentin can help reduce the severity f nystagmus (adverse effects)
When is surgery used in nystagmus
For face turns, head tilts, chin elevation, or any anomalous head position
What is the Kestenbaum technique
Commonly used to shift the null point closer to the primary position and eliminate the head turn
Nystagmus intensity is reduced, VA is improved, null point is wider
What should you consider before doing surgery in nystagmus
Only for significant head turn (small turns are managed with yoked prisms)
Best when done in children older than 4yoa.
Have to reoperate in 50% of cases
What is spontaneous vertical deviation
Spontaneous upward movement of one or both eyes when tired, fusion is broken, or inattentive
Found with infantile strabismus
What is the presentation of dissociated vertical deviation
No symptoms
2-3 yoa
Hyperdeviation in one or both eyes (the other eye does not have hypo deviation)
Can be spontaneous(manifest) or when one eye is covered (latent)
Nystagmus can als be present
How do you treat dissociated vertical deviation
Surgical treatment only if large or occurs frequently
Mostly no treatment
Difficult to measure
What is inferior oblique overaction
The eye is elevated in ADDuction
Present in children with infantile strabismus
Bilateral or unilateral
Little or no deviation in primary
Found in 2/3 of children with congenital strabismus
Surgery only if large
What is pattern strabismus
Present when a horizontal deviation changes in magnitude between up gaze and down-gaze
Vertical
Non-Comitant
In XT or ET
Cause is unknown
What is V pattern
Horizontal deviation is more divergent in up-gaze than in down-gaze
What is A pattern
Horizontal deviation is more divergent in down-gaze than in up-gaze
How do you determine A/V pattern
Measure the alignment in primary at distance(with habitual) and then about 25 degrees from primary in up-age and down-gaze
V pattern significance
Significant when difference between up-gaze and down-gaze is at least 15pd
Most common
Can be seen in infantile ET
In patients with SO palsies (is bilateral especially)
Pt may adopt a chin up compensatory head posture
What is the significance of A pattern
Significant when difference between up-gaze and down-gaze is at least 10pd
There is more divergence inferior
Patients with XT
May have chin down head posture
Common in patients with infantile strabismus with craniofacial malformations, and Down’s syndrome
