PUPILS Dr. Canan Aslı Yıldırım Ophthalmology

Pupillary Reactions A three-neuron arc Afferent neurons from retinal ganglion cells to pretectal area and to parasympathetic motor pool (Edinger–Westphal nucleus) of oculomotor nuclear complex Efferent parasympathetic outflow from oculomotor nerve to ciliary ganglion Efferent nerves from ciliary ganglion to pupillary sphincter

Light Reflex Pathway Optic chiasm: crossed to uncrossed fibers ~ 53:47. Crossed fibers: from nasal retinal receptors of the contralateral eye Uncrossed fibers: from temporal retinal receptors of the ipsilateral eye Pregeniculate optic tract - pupillomotor branches of afferent axons gain access to pretectal nuclear area

Pupillary Pathway

Oculosympathetic Pathways A three neuron arc. The first neuron (Preganglionic) starts in the posterior hypothalamus and terminates in the ciliospinal center of Budge. The second neuron (Preganglionic) passes to the superior cervical ganglion. The third neuron (Postganglionic) joins the ophthalmic division of the trigeminal nerve to reach the ciliary body and the pupil dilator muscle via the nasociliary and long ciliary nerves.

Sympathetic outflow to the iris dilator muscles begins in the posterolateral area of the hypothalamus and descends uncrossed through the tegmentum of the midbrain and pons Oculosympathetic Pathways

Detection and Diagnosis of Pupillary Defects: A semi-darkened room Patient views a distant object Round, equal in diameter Anisocoria : reasses pupils in varying illumination ! Dim light & poor pupillary dilation : sympathetic system dysfunction Bright light & poor pupillary constriction : parasympathetic system dysfunction The swinging-flashlight test Marcus Gunn pupil (afferent pupillary defect) Optic nerve lesion on the affected eye

Pupillary Reflexes

Near Reflex and Accommodation (1) increased accommodation of the lens (2) convergence of the visual axes of the eyes (3) pupillary constriction. Near Reflex: Patient views a distant target, then a near target. Observe both eyes to confirm the responses are equal and symmetrical.

Afferent Pupillary Defect (APD): "Marcus Gunn Pupil" : Afferent Pupillary Defect (APD) "pupillary escape" An optic nerve conduction defect is present Both pupils dilate when the abnormal eye is stimulated Swinging Flashlight Test (for optic nerve disfunction) : Grading an APD In a darkened room, patient fixating a distance object 5 complete cycles (10 sec total) ≈ a grade 4, severe defect

The Swinging Light Test NormalDefective

Patient With Abnormal Pupils Swinging flashlight test in two patients with mydriasis on the side of orbital trauma. Bright Dim R.A.P.D.

The light reflex is absent or abnormal, the near response is intact Argyll Robertson Syndrome Holmes-Adie tonic pupil syndrome Diabetes mellitus Aberrant oculomotor nerve regeneration Light-Near Dissociation

How to Interpret the Findings Pupillary disorders –Dilated pupil –Tonic pupil (Adie’s pupil) – Small pupil Horner’s syndrome Argyll Robertson pupil

Amaurotic pupil «Blind eye» an optic nerve lesion, no light perception A.) Pupils are of equal size. B.) Neither pupil reacts when the defective eye is stimulated. C.) Both pupils react when the contralateral eye is stimulated. D.) Near reflex is normal.

Essential Anisocoria Benign pupillary inequality, same in all lightening conditions Anisocoria is not enhanced in dim lighting (no sympathetic disruption) in bright illumination (no parasympathetic disruption)

Dilated Pupil Usually efferent defect + Head injury = third cranial nerve (oculomotor) compression by herniation of the tomporal lobe + Droopy lid + double vision = aneurysm Holmes-Adie’s tonic pupil Dilating eye drop

Tonic Pupil (Adie’s Pupil) Healthy young women Unilateral Benign lesion in the ciliary ganglion Denervation hypersensitivity (constriction with methacholine 2.5%, 0.125% pilocarpine) Associated with diminished deep tendon reflexes

Holmes-Adie tonic pupil syndrome Relative mydriasis in bright illumination Poor to absent light reaction Slow contraction to prolonged near effort Slow redilation after near effort Iris sphincter sector palsy Segmental vermiform movements of iris border Defective accommodation

A 52-year-old woman with right tonic pupil (left) 1 year later involvement of the left pupil developed as well (right). Holmes-Adie tonic pupil syndrome Bright Dim Convergence 0.125% pilocarpine

Disorders Associated with Tonic Pupil Polyneuropathy Idiopathic Holmes-Adie syndrome Ross syndrome Riley-Day syndrome Inflammation/Infection Forme fruste familial dysautonomia Herpes viruses Sarcoidosis Paraneoplastic polyneuropathies Ischemia Guillian-Barre syndrome Giant cell arteritis Polyarteritis nodosa Sjogren's syndrome Migraine Syphilis Orbital Trauma and Surgery

Pharmacologic Accidents – Fixed Dilated Pupil Atropine (1%)30–40 min Cyclopentolate (1%)15–60 min Homatropine (2%)10–30 min Tropicamide (1%)20–40 min Scopolamine (0.25%)15–30 min Phenylepherine (2.5%)15–60 min Hydroxyamphetamine (1%)45–60 min Cocaine (4%)40–60 min

Small Pupil Ptosis of upper eyelid + small pupil = Horner’s Synd. –Unilateral –Congenital or acquired lesion of sympathetic pathways »Carotid dissection, carotid aneurysm, tumor –4% cocaine (will not dilate desympathectomized pupil) –Hydroxyamphetamine drops (differentiation of preganglionic from postganglionic lesions)

Oculosympathetic Defects (Horner’s Syndrome) Miosis Partial ptosis Apparent enophthalmos Diminished sweat, drier skin Transient dilated conjunctival and facial vessels; facial flush; ocular hypotony; increased accommodation Heterochromia: if congenital; rarely acquired adult cases There is a total / partial interruption of the sympathetic pathway.

Horner’s Syndrome

Argyll Robertson Pupils Visual function grossly intact Decreased pupillary light reaction Intact near response Miosis Pupils irregular Bilateral, symmetrical Poor dilatation Iris atrophy variable Tertiary syphilis

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