Neurological Conditions Flashcards
how is congenital nystagmus different to infantile nystagmus?
congenital nystagmus suggests the nystagmus has been since birth (but that is very rarely the case) whereas infantile nystagmus describes nystagmus from childhood
what are the two sub types of nystagmus?
-early onset: may have developed due to visual abnormality or can be idiopathic
-acquired: neuropathological like stroke or trauma or MS
name and describe what are the three types of early onset nystagmus
-Infantile
-Latent = where you cover the eye and the nystagmus is triggered or gets worse
-Spasmus nutans = comes on with head nystagmus and usually disappears within first year of life. Its high frequency low amplitude, and is accompanied by head oscillations (as is sometimes infantile nystagmus)
when does infant nystagmus seem to occur?
when theres another pathology in the visual system that causes a moderate moderate reduction in VA (severe vision loss can make you less likely to have visual nystagmus)
what is the null zone in nystagmus?
the position of the eyes where the nystagmus is at its best. Usually is achieved by the patient having an AHP.
how can you represent movements of nystagmus?
using a wave form graph (check ss)
on a waveform graph for nystagmus, what is the frequency?
frequency = 1/ cycle duration
on a waveform graph of nystagmus what is the intensity?
intensity = amplitude x frequency
ln a waveform graph for nystagmus, what does foveation mean?
the period of time when the eyes are moving most slowly, usually occurs when the eyes have just jerked back to fixation
in a waveform graph of nystagmus where is pathology most likely to occur?
in the slow phase
in a waveform graph for nystagmus, what is jerk form?
where the eyes drift to the left and then jerk back to the right and carry on in a cycle. This can be used to record and characterise the nsytagmus
what are the 3 types of waveform for nystagmus?
-Jerk = this tends to suggest a better functioning visual system as the patient is able to re-orient their gaze to the fixation target
-Pendular
-Dual jerk
what is oscillopsia?
where the world seems to oscillate back and forth but this is rare in infantile nystagmus. Could be due to efference copy.
in an eye trace graph what are the movements for infantile nystagmus?
horizontal are like zig zag lines and theres one straight line in the middle which is vertical movements because theres basically no vertical movements
what do people with infantile nystagmus see?
usually see images blurry as blurry or coming in and out of focus and people and oscillopsia may occur when the patient is very tired
for someone with oscillopsia, what nystagmus are they most likley to have?
acquired nystagmus
what is latent nystagmus also known as?
fusion maldevelopment nystagmus syndrome
what makes latent nystagmus manifest?
when nystagmus worsens when one eye is covered
what are the signs of latent nystagmus?
*only present when one one eye is covered
* Quick phases directed towards fixating eye
* Higher intensity in abduction (follows alexanders law)
* Slow phases do not accelerate
* (Almost) always accompanied by strabismus
for spasmus nutans, what are the signs?
High frequency, low amplitude
* Accompanied by head oscillations
* Spontaneous regression within first few years of life
if you see vertical nystagmus, what nystagmus is it most likely?
probably acquired as infantile nystagmus is usually horizontal but should still be checked
what are opsoclonus and ocular flutter?
eye movements that are not nystagmus because there’s no slow phase however these are suspicious of neurological damage
what are the main signs of acquired nystagmus and what are the most common causes?
-asymmetric nystagmus
-vertical nystagmus
most commonly MS or stroke
what is the difference between opsoclonus and ocular flutter
opsoclonus is involuntary rapid eye movements in all directions while ocular flutter is also rapid eye movements they are only in the horizontal so less severe and some people can do this voluntarily
what do you need to record when recording nystagmus?
- Does it worsen with occlusion?
- Does it dampen with convergence?
- Record nystagmus in each gaze position using arrows to categorise whether its pendular, jerk or rotary
what are important questions to ask in history and symptoms for nystagmus?
-whether there’s oscillopsia as even in infantile it can occur occasionally
-whether the nystagmus has changed as that could mean it’s neurological because infantile is non-progressive and changes are not expected with age
why not use a phoropter when refracting someone with nystagmus?
as you need to let the patient be in the null zone to obtain best vision
what kind of refractive error (high or low) can you expect for someone with nystagmus?
high refractive error is common probably due to poor emmetropisation
what is typical astigmatism in someone with idiopathic nystagmus?
1.85DC - mostly corneal astigmatism thought to be due to interaction between the cornea and the lids
whats the best type of perimetry and pressure test to do on someone with nystagmus?
-microperimetry
-NCT
what tip can you encourage for children with nsytagmus?
encourage them to use their null zone as much as possible even if that means an abnormal head posture. This is to give their vision the best opportunity to develop.
(remember some individuals may have 2 null zones and the null zone may be different for distance and near)
what conditions are associated with infantile nystagmus?
- Albinism
- Achromatopsia
- Congenital cataract
- Corneal opacity
- Optic disc atrophy
- Leber’s congenital amaurosis
- Aniridia
- Retinopathy of Prematurity
- Corectopia
- Congenital stationary night blindness
- Joubert syndrome
what are associated conditions with latent nystagmus?
strabismus
what are associated conditions with acquired nystagmus?
– Stroke / multiple sclerosis most common
– Vestibular disorders
– (Various form of brain damage)
NEEDS INVESTIGATION FROM NEUROLOGY
what are the optical treatments for nystagmus?
- Contact lenses
- Base out prism
- Botox
- Biofeedback
- Acupuncture
- Intermittent photic stimulation
what are the surgical treatments for nystagmus?
- Tenotomy and reattachment
- Artificial divergence
- Anderson-Kestenbaum surgery
how can a patient benefit from infantile nystagmus treatment?
-gives the child more time to see
-improves AHP
what are the steps for treating nystagmus?
- teat the underlying condition
- correct the underlying ammetropia
what may be the best solution for visual correction for nystagmus?
contact lenses because:
-youre always looking through optical centre, unlike glasses (allows use of null zone)
-VA is often better in CLs compared to glasses
what type of nystagmus can BO prism help and how?
infantile and latent
-convergence can make nystagmus better so BO prism can be used to place the eyes in a convergent position
(always check for convergence null though as some patients require divergence so BI prism)
what are all the ways you can manage nystagmus?
-contact lenses
-base out prism (in most cases)
-botulinum toxin
-relaxation/ biofeedback/ meditation (nystagmus is worsen by stress)
-acupuncture
-pharmacological treatments
-surgery
what are the two types of surgery for nystagmus?
-null zone realignment surgery - Moving the null zone can improve posture, cosmesis, and
patient confidence
-surgery to reduce intensity - tenotomy and reattachment and artificial divergence (replaces the need for prism)
what is botulinum toxin used for in nystagmus management?
-reduces oscillopsia in acquired nystagmus
-can reduce nystagmus
what are 6 causes of headaches?
- Ametropia
- Binocular vision abnormality
- Environmental – poor lighting, glare
- Pathological
- Toxic & hypoxic
- Stress, anxiety - one of the most common types (tension headaches and these do not affect vision)
what are the symptoms of a HA caused by papillooedema?
*Diffuse or unilateral throbbing, often severe
headache (HA)
* Often pain worse when waking in the morning
* HA worse with coughing or change of posture
* Nausea and vomiting
* Vision, pupils, fields not usually affected until late
stages
*may have amaurosis fugax (temporary loss of vision in one eye)
what are the headaches that affect the eyes?
- Papilloedema
- Shingles
- Giant cell arteritis
- Migraine
- Closed angle glaucoma
what is the age of onset for migraines?
18-30 years
what are the risk factors of migraines?
- Female : male 3:1
- Up to 90% have family history
what are the two types of migraines?
common migraines - without aura
classic migraine - with aura
what is the most common headache that does not cause vision?
tension headache. bilateral, steady and does not throb
what are the worrying features of headaches?
- Short history
- Continuous
- Worsening
- General malaise (being generally unwell)
- Other symptoms
what are the less worrying features of headaches?
- Long history
- Intermittent
- Good GH
- No other problems
