PUPILS

Dr. Canan Aslı YıldırımOphthalmology

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 object5 complete cycles (10 sec total) ≈ a grade 4, severe defect

The Swinging Light TestNormal Defective

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

Any questions?