2. Pupil Responses
Card Set Information
2. Pupil Responses
How do pupil reactions change with age?
less reactive to light
more difficult to dilate
increase in dof
increase diffractive elements
reduce fundus illumination
What kind of fibres innervate sphincter muscle?
What kind of fibres innervate dilator muscle?
Afferent pathway of pupil light reflex?
RGC-> ON -> OC -> OT -> Pretectal nucleus -> EW Nucleus
Efferent pathway of pupil light reflex: parasympathetic?
EW nucleus + Accommodation fibres-> C3 -> Ciliary ganglion -> Short ciliary nerve -> Ciliary body and iris sphincter muscle
Efferent pathway of pupil light reflex: sympathetic?
Hypothalamus -> Spinal cord -> Superior cervical ganglion -> C5 -> Long ciliary nerve -> Dilator muscle
relative afferent pupil defect
afferent pathway (RGC->OC) is damaged/affected
light will not induce full pupillary light reflex
What happens in the swinging light test with RAPD
light moved from LE to RE:, LE orignally constricted, RE will dilate, LE will dilate
What is an argyll Robertson pupil?
both pupils small
no direct/consensual response
near response ok
What is the etiology of an Argyll Roberson pupil?
damage to parasympathetic pathway
: neurosyphilis lesion near EW nucleus- affects dorsal pupillary fibres (responds to light)
spares ventral pupillary fibres (accommodation)
What are some diagnostic tests for neurosyphilis?
: veneral disease research test
: rapid plasma reagin
Adie's tonic pupil?
Postganglionic para denervation of ciliary muscle and spinchter
neuronal loss in short ciliary nerves/ ciliary ganglion
Features of an adie's tonic pupil?
affect eyes is dilated and cons/dir poor
near strong but slow
constricts to 0.125%pilocarpine
damage to sympathetic pathway
Sx of horners?
pupil reactions normal
Diff between acq and congenital horners?
: neck trauma, hypo haem/tumour, lunch cancer, cavernous sinus lesion, carotid artery dissection
Test for horners?
: affected eye will dilate
: unaffected eye will dilate