Introduction to Neuro-

OphthalmologyRaed Behbehani , MD FRCSC

Neuro-ophthalmology•Diseases of the eye and the

neurological apparatus that serves it (optic nerve and chiasm, cranial nerves, visual pathways and cortex).

•60% of our brain is linked to vision

•Afferent: Optic nerve, retina, chiasm, visual pathyways, cortx.

•Efferent: Cranial nerve III,IV,VI, ocular muscles, brain stem control centers.

Afferent System

Efferent SystemCranial

Nerves III, IV, VI

Horizontal and

Vertical Gaze

CenterSmooth Pursuit

and Saccade control

Symptoms

•Loss of vision (transient, constant, mono- or binocular).

•Diplopia.

•Ptosis.

•Visual disturbances.

•Pupil irregularities.

•Eyelid or Facial spasms.

Clinical Approach

•History is the most important part or the assessment.

•“Where” is the lesion ?

• “What” can be the lesion ?

•Is this an emergency ?

Diseases of the Afferent System•Optic neuritis

•Ischemic optic neuropathy (Arteritic vs Non-Arteritic)

•Other optic neuropathies (compressive, papilledme, inflammatory, heriditary).

•Chiasmopathies.

•Strokes causing visual field defects.

Diseases of the Efferent System

•Cranial Neuropathies (III, IV, VI).

•Nystagmus.

•Ocular Myasthenia.

•Blepharospasm, Hemifacial Spasm.

•Pupillary Abnormalities.

What I can do for a patient with vision

loss?•Before you refer, you can do a lot !

•History : Sudden or chronic (urgency)

•Check visual acuity (use near vision cards).

•Check for relative afferent pupillary defect.

•Do a visual field by confrontation.

•Ophthalmoscopy.

How to check for RAPD

Visual Field by Confrontation

Direct Ophthalmoscopy

Optic Neuritis

•Sudden loss of vision.

•Pain with eye movements.

•Females > Males.

•RAPD present.

•Optic disc normal.

•MRI is important for MS risk determination.

MRI in optic Neuritis

White matter lesion predicts high risk for development of MS ( 70% over 15 years)

Ischemic Optic Neuropathy

•Age > 50.

•Acute , painless, loss of vision.

•Diabetes, hypertesnion, and hyperlipedemia.

•RAPD present.

•Ophthalmoscopy : disc edema +- hemorrhage.

Ischemic optic neuropathy

Arteritic Ischemic Optic Neuropathy•Patient > 60.

•Headache, malaise, myalgia, weight loss fever, jaw claudications, and transient loss of vision.

•ESR, CRP are high.

•Need to start systemic steroids immediately and do then do a TA biopsy.

Temporal Arteritis

Retinal Artery Occlusion

•Painless loss of vision.

•May be preceded by Amaurosis Fugax.

•Source of emboli usually carotid or cardiac.

•Less common causes: Vasuclitis (GCA, Anti-phospholipid syndrome).

•Order Carotid Doppler Study and, Echocardiography.

Central Retinal Artery Occlusion

Branch Retinal Artery Occlusion

Compressive lesions

•Slowly progressive loss of vision.

•Can by uni-lateral or bilateral.

•Pituitary tumors, craniopahryngiomas, and meningiomas of the skull base.

•Require neuro-imaging (MRI) for diagnosis.

Visual field defects

Pituitary tumors

Pituitary Tumors

Homonymous Hemianopsia

Papilledema Disc edema due to raised intracranial

pressure (mass, pseudotumor cerebri).

•Headache, transient visual obscurations, Diplopia, and tinnitus.

•Normal visual acuity and visual fields early.

•Ophthalmoscopy.

•Urgent CT scan of the head with contrast.

Papilledema

Idiopathic Intracranial Hypertension (pseudotumor

cerebri)•Women > Men (9:1) in childbearing age.

•90% of affected women are obese.

•Normal CT/MRI/MRV and CSF analysis.

•Recent weight gain (last 6 months).

•Medications-linked : Tetracycline for acne , oral contraceptives, insulin-like growth factors in children.

•Aim of treatment is stop progressive loss of vision (Diuretics and Surgery).

Diplopia

•Key question “Is it only in one eye ?” , “ Does it go away when you close either eye ?”

•Monocular diplopia is always refractive in origin (cataract, astigmatism).

•Examine lids and pupils in addition to eye movement.

•Examine all cranial nerves.

Oculomotor Nerve Palsy

Pupil-involving Third Nerve Palsy

UrgentMRI/MRA or MRI/CTA

Abducens Nerve Palsy

Trochlear Neve Palsy

•Patients complain of vertical diplopia.

•Can present with abnormal head tilt.

•Can be congenital or acquired.

Trochlear Nerve Palsy - Head Tilt

Test

Cranial Neuropathies

(III,IV,VI)•Ischemic (diabetes, hypertension

and hyperlipidemia).

•Demyelinating.

•Compressive (tumor, aneurysm).

•Trauma.

•Raised ICP.

Multiple Cranial Neuropathies

(III,IV,VI)•Ischemic cranial neuropathies are

almost always isolated.

•If multiple simultaneous CN, suspect lesion in the posterior orbit/cavernous sinus region.

•Usually due to mass lesion.

Cavernous Sinus

Ocular Myasthenia

•Myasthenic signs restricted to the ocular muscles.

•Fatiguable diplopia and ptosis.

•Ice test or rest test in the clinic demonstrate improvement.

•Acetylcholine receptor antibodies (positive in 50 % only).

•Single fiber EMG.

Ocular Myasthenia

before ice test

after ice test 2

minutes

Pupillary Abnormalities

•Anisocoria : Unequality of pupils size.

•It can be accidental discovery.

•Physiologic in 40% of patients

•It can be isolated or associated with lid or ocular motility abnormalities.

•Can be iatrogenic or self-induced (pharamacologic).

•N

Pupil Examination•Shine light directly at pupil (light

response).

•Test near response (miosis with accomodation).

•Check pupil sizes and measure it in both light and dark.

•Parasympathetic (constrict) and Sympathetic (dilate) control.

Pupil Light Reflex

Diagnosis ?

Horner Syndrome•A defect in oculosympathetic flow to

the eye (pupil does not dilate in dark).

•Ptosis, miosis and pseudo-enophtalmos.

•Internal carotid artery dissection, neck trauma or surgery, brain stem strokes (Wallerburg Syndrome), Apical lung tumors.

•Urgent MRI/MRA of the head and neck for acute Horner’s Syndrome.

Oculosympathetic Pathway

Adies Pupil•Pupil is larger with light/near dissociation

(pupil does not constrict well to light but does for near).

•Can be associated with diminished deep tendon reflexes (Holmes-Adies Syndrome).

Benign Essential Blepharospasm

Hemifacial Spasm

Summary•Neuro-ophthalmic problems of the

afferent and efferent visual system are common.

•Afferent diseases include optic nerve, chisamopathies and visual pathway diseases.

•Efferent diseases include cranial neuropathies, pupillary abnormalities and facial spasms.

•There is no substitute for good medical history and examination.