Neuro Optho [2] Flashcards
What happens to the pupil with parasympathetic dysfxn?
- example of a disorder
Mydriasis (pupils dilate)
-ie: tonic pupil
What happens to the pupil with sympathetic dysfxn?
- example of a disorder
miosis (pupils constrict)
- Horner syndrome
If anisocoria is greater in the dark, and both pupils have a normal light response, which pupil is the abnormal pupil? Is this likely due to a symp or parasymp dysfxn?
the smaller pupil is the abnormal one
Symp. dysfxn
ie: horner
If anisocoria is greater in the light, and the larger pupil has a poor response to light, which pupil is the abnormal pupil?
the larger pupil is the abnormal pupil.
Symptoms of horner syndrome
- ptosis
- miosis
- anhidrosis
Symp dys
- anisocoria in DARK
Tonic pupil
- mydriasis (poor light response)
- segmental constriction to light palsy
- better constriction to near target
- Parasymp dys
- aniscoria > in LIGHT
visual pathway
Optic nerve → chiasm → optic tract → lateral geniculate nucleus (in thalamus) → optic radiations → occipital cortex
If you have a lesion in the superior retina, which field of vision defect would you get?
Inferior defect
Does optic nerve dysfxn usually have monocular or binocular vision loss?
Monocular vision loss
What should always be present in unilateral or asymmetric optic n dysfxn?
How do we detect it?
Afferent Pupillary defect (APD) or Marcus Gunn Pupil
- optic n or optic tract dysfxn
(dysfxn in visual pathway occurs prior to synapse of retinal ganglion cell in the thalamus)
- to detect, use swinging flashlight test
(dmg is in the eye that DOESNT constrict, due to decreased light detected)
Most common cause of oscillopsia
nystagmus
Downbeat nystagmus can be due to?
Compression of the cerebellar flocculus due to arnold-chiari malformations.
- anterior semicircular canals disinhibited → eyes drift up → corrected down
(ant semicircular canals normally stimulate the eyes to move up)
