Abnormal pupils

Question 1

Normal pupil function

Answer 1

Regulates amount of light entering eye

Question 2

Pupil anatomy

Answer 2

2 muscles (sphincter and dilator) derived from neural ectoderm

Question 3

Normal pupil location

Answer 3

Slightly nasal to corneal centre

Question 4

Pupil physiology

Answer 4

Fine oscillation in size

Physiological anisocoria

Question 5

Pupil size

Answer 5

Max constriction 1mm

Max dilation 9mm

Question 6

Physiological vs pathological anisocoria

Answer 6

Pathological anisocoria varies between light and dark

Question 7

Dilator innervation

Answer 7

Sympathetic

Question 8

Sphincter innervation

Answer 8

Parasympathetic

Question 9

PNS route

Answer 9

EWP - 3rd nerve - ciliary ganglion - short ciliary nerves - eyeball - perichoroidal space - ciliaris for accomodation + sphincter for constriction

Question 10

SNS route

Answer 10

Intermediolateral horn cells from hypothalamus - sympathetic chain spinal cord - superior cervical sympathetic ganglion - carotid plexus - via ciliary ganglion - eyeball - perichoroidal space - radial mm for dilation and Muller’s mm for lid elevation

Question 11

Causes of unequal pupils

Answer 11

Posterior synechiae
Acute glaucoma
CNIII palsy
Adie's pupil
Horner's pupil

Question 12

Posterior synechiae

Answer 12

Due to iritis
Adhesions form between iris and lens
Present as irregular pupil w normal light reaction therefore difficult to detect

Question 13

Acute glaucoma

Answer 13

Increased IOP due to overproduction/underdrainage leading to CNII ischaemic damage
Present as vertically oval pupil with poor direct light reflex

Question 14

CNIII palsy

Answer 14

Dilated pupil that is not reactive to light or accommodation w ptosis + divergent squint
Medical causes (DM) = pupil spared
Surgical causes (tumour, aneurysm PCA) = pupil involved

Question 15

Adie’s pupil

Answer 15

Postganglionic sympathetic n damage
80% unilateral
Presents as semi-dilated pupil with decreased light rxn, slow dilation, decreased accommodation
Cause suspected to be viral

Question 16

Horner’s pupil

Answer 16

Presents as miosis, mild ptosis, ipsiateral facial flushing and decreased perspiration of below SCG
Congenital Horner’s assoc w iris heterochromia

Question 17

Adie’s pupil diagnostic test

Answer 17

Pilocarpine (0,1%) constriction of abn pupil

Question 18

Horner’s pupil diagnostic test

Answer 18

Cocaine (4%) abn eye no response

Epinephrine abn eye dilates

Question 19

Horner’s pupil central causes

Answer 19

Brainstem disease (trauma, vascular, demyelination)
Syringomelia
Spinal cord trauma
Wallenburg syndrome
Diabetic autonomic neuropathy

Question 20

Horner’s pupil

Answer 20

Pancoast tumour
Carotid and aortic aneurysm and dissection
Neck lesion (gland, trauma, postop)

Question 21

Horner’s pupil

Answer 21

ICA dissection
Nasopharyngeal trauma
Otitis media
Cavernous sinus thrombosis

Question 22

Differentiate between pre vs postganglionic lesion

Answer 22

Hydroxyamphetamine (1%)
Preganglionic - both pupils dilate
Postganglionic - horner’s pupils won’t dilate

Question 23

Light near dissociation

Answer 23

Argyll Robertson pupils

React poorly or not at all to light but constrict to near stimulus

Question 24

Light near dissociation mechanism

Answer 24

EW component of CNIII affected while near reflex pathway spared

Question 25

Perinaud’s syndrome

Answer 25

Upgaze
Convergence-retraction nystagmus
Light near dissociation

Question 26

Relative vs total APD

Answer 26

Relative is incomplete CNIII lesion/retinal detachment

Total is complete CNIII lesion

Question 27

TAPD

Answer 27

Absent direct AND consensual light reflex
Blind eye
Normal near reflex

Question 28

Efferent defect

Answer 28

Pupil reacts poorly to light

Fixed and dilated