#4- Neurophysiology of Ocular Motility Flashcards
(28 cards)
At what age does Alignment of eyes becomes stable: 2, 4, 6, 8 mos?
4 months
At what age does accommodation of eyes occur 2, 4, 6, 8 mos?
4 months
At what age are eyes 2/3 of adult size?: 2, 4, 6, 8 mos?
6 months
At what age is vision 20/20?: 2, 4, 6, 8 mos?
8 months
what is the qualitative vision test for infants
fixation and following-
3 examples of quantitative vision tests in infants
- preferential looking - prefer patterns
- optokinetic nystagmus - Passing objects (lines) evoke a prsuit and nystagmus response
- Visual evoked potential
Computer extracts a stimulus-related EEG signal from scalp electrodes
The Vestibulo-Ocular Response (VOR) fires at what 4 nuclei?
- Vestibular ganglion (endolymph mvmt)
- Vestibular nuclei (in brainstem)
- Ipsilateral CN III nucleus, 4. Contralateral CN VI nucleus)
where do signals for the saccidic system originate, and what sided saccades do they control (ipisi- or contra-lateral)
Visual cortex (and FEF) control contralateral saccades
What structurecontrols ipsilateral smooth pursuits?
Parieto-Occipital-Temporal Junction
What nuclei controls horizontal gaze? and what nucleus does it project output neurons to?
parapontine reticular formation projects to ipsilateral abducens nucleus
what sx are seen in I/L, C/L and convergence in Intranulcear Opthalmoplegia ?
I/L adduction defect
C/L abduction nystagmus
convergence is normal
Cause of ION:
- general
- young
- old
- others
- general = demyelination
- young = multiple sclerosis (pathognomonic)
- Old = stroke
- others = Toxicity, EtOh (wernicke’s)
Vertical gaze controlled by what 2 nuclei/pathway?
□
Interstitial nucleus of Cajal
Rostral interstitial MLF
what is seen in eyes in dorsal-midbrain syndrome?
light-near dissociation- pupils wil constrict upon convergence, but not with light
also- inability to look up quickly
Where is ;lesion (specifically) in dorsal midbrain syndrome and what are 2 major causes?
lesions in posterior commissure
caused by pinealomas and shunt malfunctions
superior rectus an inferior rectus have what 3 mvmts of eye each?
SR: intort, elevate, adduct
IR: depress, extort, adduct
what are 2 causes of strabismus and one result?
CNS lesion (e.g.,tumor) or vision loss may cause strabismus
-may result in vision loss dt ambylopia
define esotropia, exotropia, hypertropia
Esotropia: one eye deviated medially
Exotropia: one eye deviated laterally
Hypertropia: one eye up
define concomittant and incomittant strabismus
concommitant: same misalignment in all directions of gaze
incommitant: different misalignment in different gazes
What type of strabismus is accomodative esotropia? (concommitant or incommitant) and what is it’s pathogenesis?
concommitant strabismus
-caused by blurry vision which causes th child to accommodate which is always accompanied by convergence
What is tx for accomodative esotropia?
glasses
What is an example of incommitant paralytic strabismus
CN VI palsy
When do you need to get MRI to rule out aneurysm in CNIII palsy?
if the pupil is involved
How will pt present with CN IV palsy
head tilt to opposite side
