9/22/2015
The Pupil: A Window on the Visual System
Steven A. Newman, M.D. University of Virginia Charlottesville, VA
Financial Disclosure
• Are you kidding? • I’m a Neuro-ophthalmologist.
The Problem • What the pupils look like when seen by the surgeon (68yo referred for cataracts, glaucoma presenting with decreased vision):
1 9/22/2015
Pupil – A Little History
• Galen (2 nd Century AD): Cataract did not cause anisocoria • Covering one eye resulted in slight pupillary dilatation • Covering a blind eye would not produce dilatation • Based on Galen: if the opposite pupil did not dilate when covering an eye couching for cataract was not likely to improve vision
Pupil – A Little History
• 1855 von Graefe: “warned ophthalmologists not to be in such a hurry with dilating drops that they missed important pupillary signs.”
The Iris Free Zone
• What do you call the hole in a donut?
• ?George
2 9/22/2015
Pupil - Introduction
• Window on the eye and visual system • End organ to the IIIrd and sympathetics • Anterior portion of the uveal tract
Pupil - Introduction
• One objective sign in neuro-ophthalmology – Very useful in functional or non-cooperative patients – Sort optic nerve from retina and media • Separate afferent from efferent pathology – Fixed pupil/anisocoria: efferent – Afferent pupillary defect: afferent
Pupil – Final Pathway
• Sphincter: – 1mm wide – Posterior – 70 separate segments – Parasympathetic
3 9/22/2015
Pupil – Final Pathway
• Dilator: – Radial – Stop .3mm short of margin – Sympathetic innervation – Pigmented myoepithelial cells
Pupil – 4 Neuron Arc
• Retina – optic nerve – tract – pretectal nuclei • Pretectal nuclei – posterior commissure – Edinger-Westphal complex • Edinger-Wesphal nucleus – IIIrd nerve (inferior division) – ciliary ganglion • Ciliary ganglion – short ciliary nerves – pupillary sphincter
Pupil – Anatomy - Parasympathetics
• Leave Edinger-Westphal nucleus • Travel w/ fascicular III • Peripheral in subarachnoid III • Inferior division III • Inferior oblique branch • Ciliary ganglion (synapse) • Short posterior ciliary nerves • Innervate sphincter and ciliary body
4 9/22/2015
Pupil – Anatomy - Sympathetics • Hypothalamus (supraoptic nucleus) • Intermediolateral column • Ciliospinal nucleus of Budge-Waller • Ventral ramus • Paraspinal sympathetics • Pericarotid complex • Superior cervical ganglion • Pericarotid – cavernous – VI • Nasociliary branch V – ciliary ganglion
PERRLA
Is It Regular?
5 9/22/2015
Pupil Irregularity
• Congenital – Coloboma • Acquired – Traumatic – Inflammatory – Ischemia – Degenerative
Pupil Size
• Balance tone – Sympathetic – Parasympathetic • Pharmacologic • Neurologic • Local effects
Pupil – Size - Background
• Ambient light • Retinal adaptation • Sleep: loss sympathetic • Arousal: increase sympathetic • Lid closure: increase parasympathetic • Ciliospinal reflex: increase sympathetic
6 9/22/2015
Pupil – Size - Miscellaneous
• Age: increasing miosis • Iris color: light iris larger • Severe miosis – Pontine hemorrhage – Narcotics – Phospholine iodide
Mydriasis
• Trauma • Pharmacologic • IIIrd nerve dysfunction
Are They Equal?
7 9/22/2015
Anisocoria
• Noticeable in >20% population – Increase with age – 5% >1mm – >50% >.2mm • Afferent system pathology will not cause anisocoria
Anisocoria
• Goldilocks question – Small pupil too small – Large pupil too large • Record pupil size – Pupil gauge – Photographs • Examine in dim light/bright light • Fellow travelers – Lid position – Motility
Anisocoria - Essential
• Difference equal in light and dark • May be variable • Occasionally reverse
8 9/22/2015
Anisocoria – Small Pupil
• Anisocoria greater in the dark • Local pathology – Inflammation – Posterior synechiae • Pharmacologic (miotics) • Horner’s syndrome
Horner’s Syndrome
• Loss of sympathetic innervation • Clinical signs – Miosis – Ptosis – Anhidrosis – ? Increase accommodation • Congenital – Heterochromia
Horner’s - Diagnosis • Exclude local pathology • Pharmacologic – Cocaine test – Apraclonidine test
9 9/22/2015
Horner’s - Diagnosis • Exclude local pathology • Pharmacologic – Cocaine test – Apraclonidine test
Baseline Horner’s in Dark
Post-apraclonidine OU
Horner’s - Location
• First order – Long tract signs – Brainstem pathology • Second order – Neck – Lung apex • Third order – Carotid – Cavernous sinus
Horner’s - Localization • Fellow travelers • Pharmacologic testing – Paredrine test (release norepi): dilate (3 rd intact)
10 9/22/2015
Horner’s - Localization • Fellow travelers • Pharmacologic testing – Paredrine test (release norepi): no dilate (3 rd involved)
Horner’s - Workup
• Indications – All first/second order – Non-isolated third order • MRI – Brainstem – Neck/lung apex • MRA – R/o dissection
Anisocoria – Large Pupil • Anisocoria greater in the light • Local pathology – Inflammation – Posterior synechiae • Pharmacologic (mydriatics) – Jimson weed • IIIrd nerve palsy • Adie’s syndrome
11 9/22/2015
Large Pupil – Local Pathology
• Sphincter damage following cataract surgery • Traumatic mydriasis • Angle closure • Old inflammation – Posterior synecchiae – Pigment on lens capsule
Pupil - Unusual Syndromes
• Urrets-Zavalia syndrome: following PK (others), speculate about iris ischemia • Unrecognized cycloplegia: scopolamine patch
Anisocoria – IIIrd Nerve Palsy
• ALWAYS w/ motility disturbance • Associated ptosis • ? Reactivity
12 9/22/2015
Adie’s Syndrome
• Post-ganglionic denervation – Post viral – Traumatic • Sphincter paralysis • Vermiform movements • Regional corneal hypesthesia • Depressed deep tendon reflex
Adie’s Syndrome • Clinical findings – Dilated pupil (less with age) – Light/near dissociation – Vermiform movements • Pupillary drug testing – Hypersensitivity 1/10% pilocarpine
Adie’s syndrome
Following 1/10% pilo
13 9/22/2015
Pupillary Drug Testing
• Pilocarpine – 1/10% pilocarpine: hypersensitivity Adie’s – 1% pilocarpine: normal sensitivity (IIIrd) – 4% pilocarpine: confirm pharmacologic blockade • Cocaine – Failure dilate: 2nd & 3rd order Horner’s • Apraclonidine – Will dilate the suprasensitive smaller pupil • Paredrine – Failure dilate: 3rd order Horner’s
Does the pupil react?
If not does it react to near?
14 9/22/2015
Light Near Dissociation
• Midbrain – Argyll Robertson pupil – Dorsal midbrain syndrome • Ciliary ganglion – Adie’s syndrome • Long posterior ciliary nerve – Pan retinal photocoagulation • Bilateral optic neuropathy
Argyll Robertson Pupil
• Midbrain microvascular pathology – Syphilis – Diabetes • Small irregular pupil • Brisk reaction to near • Rapid redilate • Poor dilatation to atropine
Argyll Robertson Pupil - LN
15 9/22/2015
Argyll Robertson Pupil
• Other evidence of neuro-syphilis – Tabes dorsalis – Charcot joint • Serology – VDRL – FTA-ABS
Light Near Dissociation
• Midbrain – Argyll Robertson pupil – Dorsal midbrain syndrome • Ciliary ganglion – Adie’s syndrome • Long posterior ciliary nerve – Pan retinal photocoagulation • Bilateral optic neuropathy
Dorsal Midbrain Syndrome
• Clinical – Absent up gaze – Retraction convergence nystagmus – Collier’s sign • Pathology – Pineal tumor – Midbrain tumor – Dilated IIIrd ventricle • Associated – Papilledema
16 9/22/2015
Light Near Dissociation
• Midbrain – Argyll Robertson pupil – Dorsal midbrain syndrome • Ciliary ganglion – Adie’s syndrome • Long posterior ciliary nerve – Pan retinal photocoagulation
Light Near Dissociation – Adie’s
If yes does it react equally?
17 9/22/2015
Hippus
• Pupil normally rebounds after constriction • Variable • Should be equal
Afferent Pupillary Defect
• Most important objective sign in ophthalmology • Indication of asymmetric optic nerve function • Correlates with visual field loss • Exceptions – Mild w/ amblyopia – With large retinal pathology – Contralateral to tract
History
• Marcus Gunn (1904): described asymmetric response to covering each eye in the setting of optic nerve dysfunction • Kestenbaum (1946): popularized testing for an afferent pupillary defect and introduced the eponym "Marcus Gunn pupil" • Levatin: described the swinging flashlight test
18 9/22/2015
Regulate the Amount of Light Coming In
• Central "computer" to summate amount of light from each eye
Examination Techniques
• Every patient should be screened for an afferent pupillary defect • Fix accommodation – Visible distant Snellen letter – Dark room • May need to side light the eye to observe especially with dark iris
Examination Techniques
• Only one working pupil is necessary to observe for an APD
19 9/22/2015
Examination Techniques • Light source • Bright – Muscle light – Indirect • Not so bright as to produce an aversive reaction
Examination Techniques
• Equal time on each pupil • Rapid movement between eyes • Watch for the initial pupillary reaction • Secondarily – Observe the amount of contraction – Look for escape
20 9/22/2015
A Little More History • Fineberg & Thompson (1979): quantitate APD with neutral density filters
Quantitation APD
• Subjective gradation: 1-4+ scale • Patient subjective gradation: relative brightness • Neutral density filters – .3log steps (50% reduction in the amount of light) – Place over the better reacting pupil until equalized • Pupilometer (infrared)
Quantitation APD
• Filters in .3log steps • Additive
21 9/22/2015
Implications of APD
• Anterior segment pathology (corneal opacity/cataract) DOES NOT produce APD
Conclusions
• Three pupillary questions (remember PERRLA) – Regular? – Equal? – Reactive? • You don’t have to be a professor to learn a lot from a pupil
22