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.