2. Pupil Responses
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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
- RE affected,
- 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
- possible: neurosyphilis lesion near EW nucleus- affects dorsal pupillary fibres (responds to light)
- spares ventral pupillary fibres (accommodation)
What are some diagnostic tests for neurosyphilis?
- VDRT: veneral disease research test
- RPR: 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?
- unliteral, f>m
- affect eyes is dilated and cons/dir poor
- near strong but slow
- constricts to 0.125%pilocarpine
- vermiform movements
- damage to sympathetic pathway
- pupillodilator dysfunction
Sx of horners?
- unilateral miosis
- facial anhydrosis
- pupil reactions normal
Diff between acq and congenital horners?
- congenital: heterochromia
- acquired: neck trauma, hypo haem/tumour, lunch cancer, cavernous sinus lesion, carotid artery dissection
Test for horners?
- apraclonodine: affected eye will dilate
- cocaine: unaffected eye will dilate
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