VN - Nystagmus - Week 11 Flashcards
List 18 components of neurological testing in an optometric setting.
External exam
-proptosis, ptosis, lid retraction etc
VA with current Rx
Confrontation
-amsler + red cap
Ishihara CV
-monocular
Pupils including size
Oculomotility
Smooth pursuit
Saccades
-horizontal, vertical, oblique
Convergence
Cover test
Blood pressure/heart rate (automatic)
Fundus photo
OCT
VF (central/30-2)
-neuro setting possibly too long
CN testing
Mental testing
Sensory testing
Reflex testing
At what VA with Rx should you pinhole?
If worse than 6/9
Describe the measurement for the palpebral fissure aperture. Note the normal results and what is abnormal.
Distance between the upper and lower eyelids
Normal - 9 to 11mm
Abnormal <9mm
Describe the marginal reflex distances, what normal values are, and abnormal values (2).
Distance between the lids and the corneal reflex
Normal 4-5mm
Abnormal <4mm or 1.5mm asymmetry between MRD1/MRD2
Describe how levator function is taken, the normal value, and abnormal value (3).
Distance between excursion of upper lid margin from full down gaze to full up gaze without brow movement
Normal >10mm
Abnormal
-good 8 to 10mm
-moderate 5 to 7mm
-poor <4mm
Describe how the lid crease is assessed. Note the normal values in men and women, and what is abnormal (2).
Distance from the upper lid margin to the lid crease
Women - 10 to 11mm
Men - 8 to 9mm
If the lid crease is higher than normal or if there is a deeper upper lid sulcus
List four things that can be asked of the patient as part of mental screening.
Ask exact time (day/month/year)
Ask the patient to repeat three simple words. Ask them to repeat it in five minutes
Ask who our prime minister is
Ask a patient to spell a simple word forward and backword
List 5 components of cerebellar function testing.
Finger to nose test
Rapid alternating movements
-pat their thighs
Rombergs test
-stand straight, eyes closed
Dynamic rombergs test
-march on the spot, hands out
How do cerebellar lesions affect saccades and nystagmus? Which side is affected?
Same side as the lesion is affected
Saccades over/undershoot
Jerk nystagmus
Which way do patients tild their head with a superior oblique palsy?
Head tilt to the opposite side
List 6 optometric exams that assess CN2 function.
VA
VF
CV
Amsler
Pupils
ONH exam
List 2 optometric exams that assess CN3 function.
Pupils and oculomotility, including levator and lids
What does superior oblique palsy indicate (which CN)?
CN4
What two corneal nerves can corneal sensation indicate?
CN5 or 7
CN6 controls what eye muscle?
Lateral rectus
What can poor CN7 function result in?
Facial paralysis
-bells palsy
List 4 CN8 function tests that can be done in an optometric setting.
Finger rubbing test
Tuning fork test
-rinnes test
Head impulse test
Dix-hallpike test
-sit upright, rotate head
Describe rinnes test, including what the different test results mean (2).
Air conduction vs bone conduction (mastoid bone)
Sensori-neural loss vs conductive hearing loss
BC>AC indicates conductive loss (middle ear)
AC>BC indicates normal/sensori-neural loss (inner ear)
Describe how to assess the function of CN9 and 10.
Observe the uvula for any sideway deviations
Palate should rise symmetrically with little nasal air
Describe how to assess CN11 function.
Have the patient shrug their shoulders and turn their heads against resistance
Describe how to assess CN12 function.
Stick out tongue
-should be straight
List 2 ways a patients sensory input can be assessed.
With closed eyes, have the patient tell between sharp and dull stimulation
Bend their big toe with their eyes closed, ask them which way it is bent
Describe how dynamic VA is tested and what is vital to ensure proper testing.
Rotate head longer and see if there is any impact on VA
-no more than 1 line drop
Duration and speed are vital
Describe what is meant by infantile nystagmus. Can it occur in later life?
An involuntary ocular motor oscillation that manifests at or shortly after birth
-rarely occurs later in life
It persists thoughout life
What is infantile nystagmus associated with?
An underlying disorder of the visual system
What percentage of individuals with infantile nystagmus will exhibit strabismus?
30%
Describe wehther infantile nystagmus is uni- or bilateral, conjugate, and symmetrical in terrms of amplitude.
It is characteristically bilateral, conjugate and similar amplitude in both eyes
Describe what happens to the severity/magnitude of infantile nystagmus with fixation effort, stress, and motivation.
It worsens with all three
What happens to infantile nystagmus severity/magnitude with convergence? What about voluntary lid closure? What about sleep?
Dampens with convergence and lid closure
Abolished by sleep
Describ what is meant by a foveation period in describing nystagmus.
Portion of the waveform of a nystagmus where the image of the point of regard is on or near the fovea and the eyes are stationary
Can waveforms of infantile nystagmus change with age?
Yes
Do waveforms of infantile nystagmus vary with different gaze directions?
Yes
What is an important diagnostic indicator of infantile nystagmus regarding its oscillations?
It always remains horizontal, regardless of gaze position
What is meant by the null zone?
Field of gaze in which nystagmus intensity is minimal and has the best foveation period
What can the null zone lead patients to do?
Patients can exhibit a null zone laterally, so an abnormal head posture may be adopted to shift the eyes into the null zone
-minimises nystagmus intensity and maximises visual acuity
List 5 questions you can ask if you suspect infantile nystagmus (workup).
Do you experience oscillopsia
Does it get worse when you are tired, sick, stressed etc
When you turn your head/face, to your preferred position, does it get better
Has the patient noticed anything unusual/different when they are reading/playing with toys
Has the teacher noticed any issues at school
If you suspect infantile nystagmus, describe how you would assess VA and refraction.
Assess looking straight ahead, and again with preferred head posture
Check if there is a difference
Describe how you would do cover test differently if you suspect infantile nystagmus and also note what you would look out for.
Perofrm slower than usual
Look for a change in nystagmus dirrection as you cover/uncover
What should you look out for when doing oculomotility and you suspect infantile nystagmus?
Does the nystagmus change in different gaze positions with head straight
-is it always horizontal
What should you look out for when doing convergence and you suspect infantile nystagmus?
Does it dampen with convergence
Is eye movement recording essential for nystagmus or can you just skip it?
Essential
List the four types of waveforms of nystagmus and note what they look like.
Pendular
-like a sine wave (sinusoidal)
Linear/constant velocity
-sawtooth/factory roof
Accelerating
-exponential curve followed by a cliff - repeating
Decelerating
-logarithmic curve followed by a cliff - repeating
Is there a cure for infantile nystagmus?
No
What kind of refractive error is associated with infantile nystagmus?
High with the rule astigmatism
Describe how version prisms can aid individuals with infantile nystagmus.
In those with an eccentric null zone, it can help push the visual scene laterally and dampen the nystagmus
Describe how vergence prisms can be used to help individuals with infantile nystagmus. Note a good starting approach.
Induces convergence to reduce nystagmus
An approach is to begin with 7 prism D BO in combination with -1.00DS to offset accommodation
What is the most beneficial combination of therapy for infantile nystagmus (2)?
Surgery followed by combination prisms
List two possible pharmacological interventions for infantile nystagmus. Describe a possibility of what may be occurring with these drugs.
Memantine
Gabapentin
-possible that INS reduction
What is the principle aim of surgical management of infantile nystagmus (2)?
Moving the null zone to the primary gaze position to correct abnormal head tilts/turns
Also to broaden the null region and minimise nystagmus at all angles
Describe the anderson-kestenbaum procedure for infantile nystagmus.
Recession of part of the pair of rectus muscles responsible for the direction of face turn or the antagonist muscles
What is the mainstay of infantile nystagmus treatment?
Surgery
